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1.
  • Selegård, Robert, 1934- (författare)
  • Polypeptide functionalized gold nanoparticles for bioanalytical applications
  • 2014
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Detection strategies that allow for simple, rapid, cost efficient and sensitive monitoring of proteins and their interactions with biomolecules are of great importance in drug development and diagnostics. This thesis describes the development of bioanalytical applications based on the tunable self-assembly of gold nanoparticles functionalized with a de novo designed polypeptide. Strategies for protein affinity sensing and for detection of several fundamentally important biological processes have been investigated, including Zn2+-mediated coordination between polypeptides and low molecular weight chelants and protease and phosphatase activity.A Zn2+ responsive synthetic polypeptide designed to fold into a helix-loop-helix motif and dimerize into a four-helix bundle has been used to control the stability and self-assembly of gold nanoparticles. This polypeptide has a high negative net charge at neutral pH as a consequence of its many glutamic acid residues, efficiently preventing folding and dimerization due to charge repulsion. Zn2+ coordination provides a means to trigger folding and dimerization at neutral pH. The polypeptide can be readily attached to gold nanoparticles via a cysteine residue in the loop region, retaining its folding properties and responsiveness to Zn2+. The polypeptide functionalized gold nanoparticles display excellent colloidal stability but aggregate reversibly after addition of millimolar concentrations of Zn2+. Aggregates are dense with a defined interparticle distance corresponding to the size of the four-helix bundle, resulting in a distinct red shift of the localized surface plasmon resonance band.Three completely different strategies for colorimetric biosensing have been developed, all being based on the same responsive hybrid nanomaterial. In the first strategy a synthetic receptor was co-immobilized on the gold nanoparticles together with the Zn2+ responsive polypeptide. Protein analyte binding to the receptor could be detected as this interaction sterically prevented aggregation induced by Zn2+. In the second strategy the reduction in colloidal stability caused by specific proteolytic cleavage of the immobilized polypeptide was exploited to monitor the enzymatic activity. The third strategy utilized the sensitivity of the system to small variations in Zn2+ concentration. The presence of low molecular weight chelants was found to influence the mode of aggregation, both by sequestering Zn2+ and through the formation of ternary complexes involving the polypeptides, which prevented dimerization and thus aggregation. This approach was further developed into a generic concept for phosphatase detection exploiting the different affinity of enzyme substrates and reaction products for Zn2+.The flexibility of the different detection schemes enables detection of a large number of analytes by exploiting the tunable stability of the nanoparticles and the possibilities to effectively decouple the recognition event and the nanoparticle stability modulation.
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2.
  • Tran, Thuy, 1980-, et al. (författare)
  • Real-Time Nanoplasmonic Sensor for IgG Monitoring in Bioproduction
  • 2020
  • Ingår i: Processes. - : MDPI. - 2227-9717. ; 8:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Real-time monitoring of product titers during process development and production of biotherapeutics facilitate implementation of quality-by-design principles and enable rapid bioprocess decision and optimization of the production process. Conventional analytical methods are generally performed offline/at-line and, therefore, are not capable of generating real-time data. In this study, a novel fiber optical nanoplasmonic sensor technology was explored for rapid IgG titer measurements. The sensor combines localized surface plasmon resonance transduction and robust single use Protein A-modified sensor chips, housed in a flexible flow cell, for specific IgG detection. The sensor requires small sample volumes (1-150 mu L) and shows a reproducibility and sensitivity comparable to Protein G high performance liquid chromatography-ultraviolet (HPLC-UV). The dynamic range of the sensor system can be tuned by varying the sample volume, which enables quantification of IgG samples ranging from 0.0015 to 10 mg/mL, without need for sample dilution. The sensor shows limited interference from the sample matrix and negligible unspecific protein binding. IgG titers can be rapidly determined in samples from filtered unpurified Chinese hamster ovary (CHO) cell cultures and show good correlation with enzyme-linked immunosorbent assay (ELISA).
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3.
  • Abrahamsson, Annelie, et al. (författare)
  • Increased matrix stiffness enhances pro-tumorigenic traits in a physiologically relevant breast tissue- monocyte 3D model
  • 2024
  • Ingår i: Acta Biomaterialia. - : ELSEVIER SCI LTD. - 1742-7061 .- 1878-7568. ; 178, s. 160-169
  • Tidskriftsartikel (refereegranskat)abstract
    • High mammographic density, associated with increased tissue stiffness, is a strong risk factor for breast cancer per se . In postmenopausal women there is no differences in the occurrence of ductal carcinoma in situ (DCIS) depending on breast density. Preliminary data suggest that dense breast tissue is associated with a pro -inflammatory microenvironment including infiltrating monocytes. However, the underlying mechanism(s) remains largely unknown. A major roadblock to understanding this risk factor is the lack of relevant in vitro models. A biologically relevant 3D model with tunable stiffness was developed by cross -linking hyaluronic acid. Breast cancer cells were cultured with and without freshly isolated human monocytes. In a unique clinical setting, extracellular proteins were sampled using microdialysis in situ from women with various breast densities. We show that tissue stiffness resembling high mammographic density increases the attachment of monocytes to the cancer cells, increase the expression of adhesion molecules and epithelia-mesenchymal-transition proteins in estrogen receptor (ER) positive breast cancer. Increased tissue stiffness results in increased secretion of similar pro-tumorigenic proteins as those found in human dense breast tissue including inflammatory cytokines, proteases, and growth factors. ER negative breast cancer cells were mostly unaffected suggesting that diverse cancer cell phenotypes may respond differently to tissue stiffness. We introduce a biological relevant model with tunable stiffness that resembles the densities found in normal breast tissue in women. The model will be key for further mechanistic studies. Additionally, our data revealed several pro-tumorigenic pathways that may be exploited for prevention and therapy against breast cancer.
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4.
  • Aili, Daniel, 1977-, et al. (författare)
  • Colorimetric Protein Sensing by Controlled Assembly of Gold Nanoparticles Functionalized with Synthetic Receptors
  • 2009
  • Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 5:21, s. 2445-2452
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel strategy is described for the colorimetric sensing of proteins, based on polypeptide-functionalized gold nanoparticles. Recognition is accomplished using a polypeptide sensor scaffold designed to specifically bind to the model analyte, human carbonic anhydrase II (HCAII). The extent of particle aggregation, induced by the Zn2+-triggered dimerization and folding of a second polypeptide also present on the surface of the gold nanoparticle, gives a readily detectable colorimetric shift that is dependent on the concentration of the target protein. In the absence of HCAII, particle aggregation results in a major redshift of the plasmon peak, whereas analyte binding prevented the formation of dense aggregates, significantly reducing the magnitude of the redshift. The versatility of the technique is demonstrated using a second model system based on the recognition of a peptide sequence from the tobacco mosaic virus coat protein (TMVP) by a recombinant antibody fragment (Fab57P). Concentrations down to approximate to 10 nM and approximate to 25 nM are detected for HCAII and Fab57P, respectively. This strategy is proposed as a generic platform for robust and specific protein analysis that can be further developed to monitor a wide range of target proteins.
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5.
  • Aili, Daniel, et al. (författare)
  • Colorimetric sensing: Small 21/2009
  • 2009
  • Ingår i: Small. - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 5:21
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The cover picture illustrates a novel concept for colorimetric protein sensing based on the controllable assembly of polypeptide-functionalized gold nanoparticles. Recognition of the analyte is accomplished by polypeptide-based synthetic receptors immobilized on gold nanoparticles. Also present on the particle surface is a de novo-designed helix-loop-helix polypeptide that homodimerizes and folds into four-helix bundles in the presence of Zn2+, resulting in particle aggregation. Analyte binding interferes with the folding-induced aggregation, giving rise to a clearly detectable colorimetric response.
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6.
  • Arja, Katriann, et al. (författare)
  • Self-Assembly of Chiro-Optical Materials from Nonchiral Oligothiophene-Porphyrin Derivatives and Random Coil Synthetic Peptides
  • 2023
  • Ingår i: ChemPlusChem. - : Wiley. - 2192-6506. ; 88:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Biomimetic chiral optoelectronic materials can be utilized in electronic devices, biosensors and artificial enzymes. Herein, this work reports the chiro-optical properties and architectural arrangement of optoelectronic materials generated from self-assembly of initially nonchiral oligothiophene−porphyrin derivatives and random coil synthetic peptides. The photo-physical- and structural properties of the materials were assessed by absorption-, fluorescence- and circular dichroism spectroscopy, as well as dynamic light scattering, scanning electron microscopy and theoretical calculations. The materials display a three-dimensional ordered helical structure and optical activity that are observed due to an induced chirality of the optoelectronic element upon interaction with the peptide. Both these properties are influenced by the chemical composition of the oligothiophene−porphyrin derivative, as well as the peptide sequence. We foresee that our findings will aid in developing self-assembled optoelectronic materials with dynamic architectonical accuracies, as well as offer the possibility to generate the next generation of materials for a variety of bioelectronic applications. 
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7.
  • Aronsson, Christopher, et al. (författare)
  • Dynamic peptide-folding mediated biofunctionalization and modulation of hydrogels for 4D bioprinting
  • 2020
  • Ingår i: Biofabrication. - : Institute of Physics Publishing (IOPP). - 1758-5082 .- 1758-5090. ; 12:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Hydrogels are used in a wide range of biomedical applications, including three-dimensional (3D) cell culture, cell therapy and bioprinting. To enable processing using advanced additive fabrication techniques and to mimic the dynamic nature of the extracellular matrix (ECM), the properties of the hydrogels must be possible to tailor and change over time with high precision. The design of hydrogels that are both structurally and functionally dynamic, while providing necessary mechanical support is challenging using conventional synthesis techniques. Here, we show a modular and 3D printable hydrogel system that combines a robust but tunable covalent bioorthogonal cross-linking strategy with specific peptide-folding mediated interactions for dynamic modulation of cross-linking and functionalization. The hyaluronan-based hydrogels were covalently cross-linked by strain-promoted alkyne-azide cycloaddition using multi-arm poly(ethylene glycol). In addition, a de novo designed helix-loop-helix peptide was conjugated to the hyaluronan backbone to enable specific peptide-folding modulation of cross-linking density and kinetics, and hydrogel functionality. An array of complementary peptides with different functionalities was developed and used as a toolbox for supramolecular tuning of cell-hydrogel interactions and for controlling enzyme-mediated biomineralization processes. The modular peptide system enabled dynamic modifications of the properties of 3D printed structures, demonstrating a novel route for design of more sophisticated bioinks for four-dimensional bioprinting. © 2020 The Author(s). Published by IOP Publishing Ltd.
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8.
  • Aronsson, Christopher, et al. (författare)
  • Zinc-Triggered Hierarchical Self-Assembly of Fibrous Helix-Loop-Helix Peptide Superstructures for Controlled Encapsulation and Release
  • 2016
  • Ingår i: Macromolecules. - : AMER CHEMICAL SOC. - 0024-9297 .- 1520-5835. ; 49:18, s. 6997-7003
  • Tidskriftsartikel (refereegranskat)abstract
    • We demonstrate a novel route for hierarchical self-assembly of sub-micrometer-sized peptide superstructures that respond to subtle changes in Zn2+ concentration. The self-assembly process is triggered by a specific folding-dependent coordination of Zn2+ by a de novo designed nonlinear helix-loop-helix peptide, resulting in a propagating fiber formation and formation of spherical superstructures. The superstructures further form larger assemblies that can be completely disassembled upon removal of Zn2+ or degradation of the nonlinear peptide. This flexible and reversible assembly strategy of the superstructures enables facile encapsulation of nanoparticles and drugs that can be released by means of different stimuli.
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9.
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10.
  • Bengtsson, Torbjörn, 1955-, et al. (författare)
  • Dual action of bacteriocin PLNC8 alpha beta through inhibition of Porphyromonas gingivalis infection and promotion of cell proliferation
  • 2017
  • Ingår i: Pathogens and Disease. - : Oxford University Press. - 2049-632X. ; 75:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Periodontitis is a chronic inflammatory disease that is characterised by accumulation of pathogenic bacteria, including Porphyromonas gingivalis, in periodontal pockets. The lack of effective treatments has emphasised in an intense search for alternative methods to prevent bacterial colonisation and disease progression. Bacteriocins are bacterially produced antimicrobial peptides gaining increased consideration as alternatives to traditional antibiotics. We show rapid permeabilisation and aggregation of P. gingivalis by the two-peptide bacteriocin PLNC8 alpha beta. In a cell culture model, P. gingivalis was cytotoxic against gingival fibroblasts. The proteome profile of fibroblasts is severely affected by P. gingivalis, including induction of the ubiquitin-proteasome pathway. PLNC8 alpha beta enhanced the expression of growth factors and promoted cell proliferation, and suppressed proteins associated with apoptosis. PLNC8 alpha beta efficiently counteracted P. gingivalis-mediated cytotoxicity, increased expression of a large number of proteins and restored the levels of inflammatory mediators. In conclusion, we show that bacteriocin PLNC8 alpha beta displays dual effects by acting as a potent antimicrobial agent killing P. gingivalis and as a stimulatory factor promoting cell proliferation. We suggest preventive and therapeutical applications of PLNC8 alpha beta in periodontitis to supplement the host immune defence against P. gingivalis infection and support wound healing processes.
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11.
  • Bengtsson, Torbjörn, 1955-, et al. (författare)
  • Plantaricin NC8 αβ exerts potent antimicrobial activity against Staphylococcus spp. and enhances the effects of antibiotics
  • 2020
  • Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The use of conventional antibiotics has substantial clinical efficacy, however these vital antimicrobial agents are becoming less effective due to the dramatic increase in antibiotic-resistant bacteria. Novel approaches to combat bacterial infections are urgently needed and bacteriocins represent a promising alternative. In this study, the activities of the two-peptide bacteriocin PLNC8 αβ were investigated against different Staphylococcus spp. The peptide sequences of PLNC8 α and β were modified, either through truncation or replacement of all L-amino acids with D-amino acids. Both L- and D-PLNC8 αβ caused rapid disruption of lipid membrane integrity and were effective against both susceptible and antibiotic resistant strains. The D-enantiomer was stable against proteolytic degradation by trypsin compared to the L-enantiomer. Of the truncated peptides, β1-22, β7-34 and β1-20 retained an inhibitory activity. The peptides diffused rapidly (2 min) through the bacterial cell wall and permeabilized the cell membrane, causing swelling with a disorganized peptidoglycan layer. Interestingly, sub-MIC concentrations of PLNC8 αβ substantially enhanced the effects of different antibiotics in an additive or synergistic manner. This study shows that PLNC8 αβ is active against Staphylococcus spp. and may be developed as adjuvant in combination therapy to potentiate the effects of antibiotics and reduce their overall use.
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12.
  • Björk, Linnea, et al. (författare)
  • Amino-Acid Side-Chain Nanoarchitectonics for Tuning the Chiroptical Properties and Supramolecular Structure of Pentameric Oligothiophenes
  • 2024
  • Ingår i: ChemPhotoChem. - : WILEY-V C H VERLAG GMBH. - 2367-0932.
  • Tidskriftsartikel (refereegranskat)abstract
    • Oligothiophenes with specific photophysical properties and molecular organization are of great interest, since this class of materials are used in organic electronics and bioelectronics, as well as biosensing. Herein, 8 different pentameric oligothiophenes, denoted proteophenes, with different amino acid substitution patterns at distinct positions along the thiophene backbone were investigated. Spectroscopic and microscopic studies of the ligands revealed the formation of optically active self-assembled materials under acidic or basic conditions. The distinct photophysical characteristics, including induced circular dichroism, as well as the supramolecular structures of the assemblies deduced from light scattering and transmission electron microscopy, were highly influenced by the positioning of distinct amino acid moieties along the thiophene backbone. Proteophenes functionalized with only glutamate residues or these functionalities in combination with hydrophobic valine moieties formed fibrillar structures with excellent chiroptical properties under acidic conditions. In addition, the amino acid functionality at the beta-position of distinct thiophene moieties influenced the induced circular dichroism pattern observed from the proteophenes. Overall, the obtained results demonstrate how changes in the position of various amino acid functionalities, as well as the chemical nature of the amino acid side chain functionality greatly affect the optical properties as well as the architecture of the self-assembled materials. Self-assembled Proteophenes. Oligothiophenes with distinct amino acid side-chain functionalities along the conjugated backbone displayed distinct chiroptical and structural properties in acidic or alkaline solutions. The distinct photophysical characteristics, as well as the supramolecular structures of the assemblies were highly influenced by the chemical nature of the amino acid, as well as the positioning of distinct amino acid moieties along the thiophene backbone.image
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13.
  • Borglin, Johan, 1986, et al. (författare)
  • Peptide Functionalized Gold Nanoparticles as a Stimuli Responsive Contrast Medium in Multiphoton Microscopy
  • 2017
  • Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 17:3, s. 2102-2108
  • Tidskriftsartikel (refereegranskat)abstract
    • There is a need for biochemical contrast mediators with high signal-to-noise ratios enabling noninvasive biomedical sensing, for example, for neural sensing and protein protein interactions, in addition to cancer diagnostics. The translational challenge is to develop a biocompatible approach ensuring high biochemical contrast while avoiding a raise of the background signal. We here present a concept where gold nanoparticles (AuNPs) can be utilized as a stimuli responsive contrast medium by chemically triggering their ability to exhibit multiphoton-induced luminescence (MIL) when performing multiphoton laser scanning microscopy (MPM). Proof-of-principle is demonstrated using peptide-functionalized AuNPs sensitive to zinc ions (Zn2+). Dispersed particles are invisible in the MPM until addition of millimolar concentrations of Zn2+ upon which MIL is enabled through particle aggregation caused by specific peptide interactions and folding. The process can be reversed by removal of the Zn2+ using a chelator, thereby resuspending the AuNPs. In addition, the concept was demonstrated by exposing the particles to matrix metalloproteinase-7 (MMP-7) causing peptide digestion resulting in AuNP aggregation, significantly elevating the MIL signal from the background. The approach is based on the principle that aggregation shifts the plasmon resonance, elevating the absorption cross section in the near-infrared wavelength region enabling onset of MIL. This Letter demonstrates how biochemical sensing can be obtained in far-field MPM and should be further exploited as a future tool for noninvasive optical biosensing.
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14.
  • Bäck, Marcus, et al. (författare)
  • Tyrosine Side-Chain Functionalities at Distinct Positions Determine the Chirooptical Properties and Supramolecular Structures of Pentameric Oligothiophenes
  • 2020
  • Ingår i: ChemistryOpen. - : Wiley. - 2191-1363. ; 9:11, s. 1100-1108
  • Tidskriftsartikel (refereegranskat)abstract
    • Control over the photophysical properties and molecular organization of pi-conjugated oligothiophenes is essential to their use in organic electronics. Herein we synthesized and characterized a variety of anionic pentameric oligothiophenes with different substitution patterns of L- or D-tyrosine at distinct positions along the thiophene backbone. Spectroscopic, microscopic, and theoretical studies of L- or D-tyrosine substituted pentameric oligothiophene conjugates revealed the formation of optically active pi-stacked self-assembled aggregates under acid conditions. The distinct photophysical characteristics, as well as the supramolecular structures of the assemblies, were highly influenced by the positioning of the L- or D-tyrosine moieties along the thiophene backbone. Overall, the obtained results clearly demonstrate how fundamental changes in the position of the enantiomeric side-chain functionalities greatly affect the optical properties as well as the architecture of the self-assembled supramolecular structures.
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15.
  • Chen, Hu, et al. (författare)
  • Detection of Matrilysin Activity Using Polypeptide Functionalized Reduced Graphene Oxide Field-Effect Transistor Sensor
  • 2016
  • Ingår i: Analytical Chemistry. - : AMER CHEMICAL SOC. - 0003-2700 .- 1520-6882. ; 88:6, s. 2994-2998
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel approach for rapid and sensitive detection of matrilysin (MMP-7, a biomarker involved in the degradation of various macromolecules) based on a polypeptide (JR2EC) functionalized reduced graphene oxide (rGO) field effect transistor (FET) is reported. MMP-7 specifically digests negatively charged JR2EC immobilized on rGO, thereby modulating the conductance of rGO-FET. The proposed assay enabled detection of MMP-7 at clinically relevant concentrations with a limit of detection (LOD) of 10 ng/mL (400 pM), attributed to the significant reduction of the net charge of JR2EC upon digestion by MMP-7. Quantitative detection of MMP-7 in human plasma was further demonstrated with a LOD of 40 ng/mL, illustrating the potential for the proposed methodology for tumor detection and carcinoma diagnostic (e.g., lung cancer and salivary gland cancer). Additionally, excellent specificity of the proposed assay was demonstrated using matrix metallopeptidase 1 (MMP-1), a protease of the same family. With appropriate selection and modification of polypeptides, the proposed assay could be extended for detection of other enzymes with polypeptide digestion capability.
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16.
  • Chen, Peng, et al. (författare)
  • Peptide functionalized gold nanoparticles for colorimetric detection of matrilysin (MMP-7) activity
  • 2013
  • Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 5:19, s. 8973-8976
  • Tidskriftsartikel (refereegranskat)abstract
    • A peptide with two cleavage sites for MMP-7 has been synthesized and immobilized on gold nanoparticles (AuNPs) through a cysteine residue. Digestion of the peptide by MMP-7 decreases its size and net charge, which leads to the aggregation of the AuNPs. The color shift caused by aggregation enables a direct and quantitative measurement of the concentration and activity of MMP-7 with an estimated limit of detection of 5 nM (0.1 μg mL−1).
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17.
  • Christoffersson, Jonas, 1986-, et al. (författare)
  • Fabrication of modular hyaluronan-PEG hydrogels to support 3D cultures of hepatocytes in a perfused liver-on-a-chip device
  • 2019
  • Ingår i: Biofabrication. - : Institute of Physics (IOP). - 1758-5082 .- 1758-5090. ; 11:1, s. 1-13
  • Tidskriftsartikel (refereegranskat)abstract
    • Liver cell culture models are attractive in both tissue engineering and for development of assays for drug toxicology research. To retain liver specific cell functions, the use of adequate cell types and culture conditions, such as a 3D orientation of the cells and a proper supply of nutrients and oxygen, are critical. In this article, we show how extracellular matrix mimetic hydrogels can support hepatocyte viability and functionality in a perfused liver-on-a-chip device. A modular hydrogel system based on hyaluronan and poly(ethylene glycol) (HA-PEG), modified with cyclooctyne moieties for bioorthogonal strain-promoted alkyne-azide 1, 3-dipolar cycloaddition (SPAAC), was developed, characterized, and compared for cell compatibility to hydrogels based on agarose and alginate. Hepatoma cells (HepG2) formed spheroids with viable cells in all hydrogels with the highest expression of albumin and urea in alginate hydrogels. By including an excess of cyclooctyne in the HA backbone, azide-modified cell adhesion motifs (linear and cyclic RGD peptides) could be introduced in order to enhance viability and functionality of human induced pluripotent stem cell derived hepatocytes (hiPS-HEPs). In the HA-PEG hydrogels modified with cyclic RGD peptides hiPS-HEPs migrated and grew in 3D and showed an increased viability and higher albumin production compared to when cultured in the other hydrogels. This flexible SPAAC crosslinked hydrogel system enabled fabrication of perfused 3D cell culture of hiPS-HEPs and is a promising material for further development and optimization of liver-on-a-chip devices.
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18.
  • Eskilson, Olof, 1992- (författare)
  • Multifunctional Nanocellulose Composite Materials
  • 2023
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Nanoparticles (NPs) are particles with more than one dimension between 1 and 100 nm. Because of their small size, they typically display different physical and chemical properties than the corresponding bulk materials. NPs have been used in many different applications, such as in electronics, optics, catalysis, and in biomedicine. Due to their colloidal nature, NPs are often immobilized on a solid substrate, such as glass or polymer-based materials, including biopolymers. Nanocellulose is a biopolymerbased nanomaterial that can be obtained from plants or bacterial biofilms. They can be processed into thin and highly hydrated films with high mechanical strength and can serve as a versatile substrate for NPs. Bacterial cellulose (BC) is also an interesting material for generating wound dressings. The combination of NPs and BC results in soft and flexible nanocomposites (BC-NPs) that can demonstrate novel properties and improve the functionality of wound dressings. BC-NP nanocomposites have previously been obtained by impregnating BC with the reactants needed for synthesis of the NPs and allowing the reaction to proceed in situ, inside and on the surface of the BC. This strategy limits the possibilities to control NP geometry and NP concentration and make synthesis of nanocomposites with more sophisticated compositions very challenging. In addition, the synthesis conditions used can potentially have negative effects on the properties of BC. The work presented in this thesis shows the possibility to produce well-defined, tunable BC-NP nanocomposites using self-assembly under very benign conditions that enable functionalization of BC with a wide range of different types of NPs. In addition to exploring the self-assembly process and the physical properties of these new BC-NP composites, several different applications were investigated. The functionalization of BC with gold nanoparticles (AuNPs) of different sizes and geometries was demonstrated. The resulting materials were used for development of a new sensor transduction technology, exploiting the optical response upon mechanical compression to detect biomolecules. BC-AuNP nanocomposites were also developed for monitoring of protease activity of wound pathogens, for catalysis, and for fabrication of ultra-black materials with unique absorption and scattering profiles of light in the visible and near infrared spectral range. In addition, the self-assembly process could be adopted for generating BC-mesoporous silica nanoparticles (MSNs) nanocomposite wound dressings. The resulting high surface area materials could be used as carriers for pH sensitive dyes. The pH-responsive BC-MSNs demonstrated adequate biocompatibility and allowed for monitoring of wound pH and for assessment of wound status. The strategies for functionalization of BC with inorganic NPs that was developed and explored in this thesis are highly versatile and allow for fabrication of a wide range of multifunctional nanocomposite materials. 
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19.
  • Eskilson, Olof, 1992-, et al. (författare)
  • Nanocellulose composite wound dressings for real-time pH wound monitoring
  • 2023
  • Ingår i: Materials Today Bio. - : Elsevier. - 2590-0064. ; 19
  • Tidskriftsartikel (refereegranskat)abstract
    • The skin is the largest organ of the human body. Wounds disrupt the functions of the skin and can have catastrophic consequences for an individual resulting in significant morbidity and mortality. Wound infections are common and can substantially delay healing and can result in non-healing wounds and sepsis. Early diagnosis and treatment of infection reduce risk of complications and support wound healing. Methods for monitoring of wound pH can facilitate early detection of infection. Here we show a novel strategy for integrating pH sensing capabilities in state-of-the-art hydrogel-based wound dressings fabricated from bacterial nanocellulose (BC). A high surface area material was developed by self-assembly of mesoporous silica nanoparticles (MSNs) in BC. By encapsulating a pH-responsive dye in the MSNs, wound dressings for continuous pH sensing with spatiotemporal resolution were developed. The pH responsive BC-based nanocomposites demonstrated excellent wound dressing properties, with respect to conformability, mechanical properties, and water vapor transmission rate. In addition to facilitating rapid colorimetric assessment of wound pH, this strategy for generating functional BC-MSN nanocomposites can be further be adapted for encapsulation and release of bioactive compounds for treatment of hard-to-heal wounds, enabling development of novel wound care materials.
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20.
  • Eskilson, Olof, 1992-, et al. (författare)
  • Self-Assembly of Mechanoplasmonic Bacterial Cellulose-Metal Nanoparticle Composites
  • 2020
  • Ingår i: Advanced Functional Materials. - : Wiley-VCH Verlagsgesellschaft. - 1616-301X .- 1616-3028. ; 30:40
  • Tidskriftsartikel (refereegranskat)abstract
    • Nanocomposites of metal nanoparticles (NPs) and bacterial nanocellulose (BC) enable fabrication of soft and biocompatible materials for optical, catalytic, electronic, and biomedical applications. Current BC-NP nanocomposites are typically prepared by in situ synthesis of the NPs or electrostatic adsorption of surface functionalized NPs, which limits possibilities to control and tune NP size, shape, concentration, and surface chemistry and influences the properties and performance of the materials. Here a self-assembly strategy is described for fabrication of complex and well-defined BC-NP composites using colloidal gold and silver NPs of different sizes, shapes, and concentrations. The self-assembly process results in nanocomposites with distinct biophysical and optical properties. In addition to antibacterial materials and materials with excellent senor performance, materials with unique mechanoplasmonic properties are developed. The homogenous incorporation of plasmonic gold NPs in the BC enables extensive modulation of the optical properties by mechanical stimuli. Compression gives rise to near-field coupling between adsorbed NPs, resulting in tunable spectral variations and enhanced broadband absorption that amplify both nonlinear optical and thermoplasmonic effects and enables novel biosensing strategies.
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21.
  • Eskilsson, Olof, et al. (författare)
  • Self-Assembly of Metal Nanoparticles in Bacterial Cellulose for the Fabrication of Soft Substrate-Supported Catalysts
  • 2024
  • Ingår i: ACS Applied Nano Materials. - : AMER CHEMICAL SOC. - 2574-0970.
  • Tidskriftsartikel (refereegranskat)abstract
    • The transition to green and sustainable catalysts necessitates efficient and safe preparation techniques using abundant and renewable resources. Many metal nanoparticles (NPs) are excellent catalysts but suffer from poor colloidal stability. NP immobilization or fabrication of metal nanostructures on solid supports can avoid issues with NP aggregation and facilitate the reuse of catalysts, but it may result in a decrease in the catalytic performance of the NPs. Here, we show that well-defined colloidal silver, gold, and platinum NPs can be self-assembled in bacterial nanocellulose (BC) membranes, yielding BC-NP nanocomposites that are highly catalytically active using the reduction of 4-nitrophenol (4-NP) as a model reaction. The large effective surface area of BC enables the assembly of large quantities of NPs, resulting in materials with excellent catalytic performance. To address the mass transport limitations of reactants through the 3D nanofibrillar BC network, the membranes were dissociated using sonication to produce dispersed nanocellulose fibrils. This process dramatically reduced the time required for the adsorption of the NPs from days to minutes. Moreover, the catalytic performance of the nanofibril-supported NPs was drastically improved. A turnover frequency above 21,000 h(-1) was demonstrated, which is more than one order of magnitude higher than that for previously reported soft substrate-supported AuNP-based catalytic materials. The ease of fabrication, abundance, and low environmental footprint of the support material, along with reusability, stability, and unprecedented catalytic performance, make BC-NP nanocomposites a compelling option for green and sustainable catalysis.
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22.
  • Iversen, Alexandra, 1997-, et al. (författare)
  • Enzymatically Triggered Peptide–Lipid Conjugation of Designed Membrane Active Peptides for Controlled Liposomal Release
  • 2024
  • Ingår i: ACS Omega. - : American Chemical Society. - 2470-1343. ; 9:17, s. 19613-19619
  • Tidskriftsartikel (refereegranskat)abstract
    • Possibilities for controlling the release of pharmaceuticals from liposomal drug delivery systems can enhance their efficacy and reduce their side effects. Membrane-active peptides (MAPs) can be tailored to promote liposomal release when conjugated to lipid head groups using thiol-maleimide chemistry. However, the rapid oxidation of thiols hampers the optimization of such conjugation-dependent release strategies. Here, we demonstrate a de novo designed MAP modified with an enzyme-labile Cys-protection group (phenylacetamidomethyl (Phacm)) that prevents oxidation and facilitates in situ peptide lipidation. Before deprotection, the peptide lacks a defined secondary structure and does not interact with maleimide-functionalized vesicles. After deprotection of Cys using penicillin G acylase (PGA), the peptide adopts an α-helical conformation and triggers rapid release of vesicle content. Both the peptide and PGA concentrations significantly influence the conjugation process and, consequently, the release kinetics. At a PGA concentration of 5 μM the conjugation and release kinetics closely mirror those of fully reduced, unprotected peptides. We anticipate that these findings will enable further refinement of MAP conjugation and release processes, facilitating the development of sophisticated bioresponsive MAP-based liposomal drug delivery systems.
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23.
  • Jury, Michael, 1984-, et al. (författare)
  • Bioorthogonally Cross‐Linked Hyaluronan–Laminin Hydrogels for 3D Neuronal Cell Culture and Biofabrication
  • 2022
  • Ingår i: Advanced Healthcare Materials. - : Wiley. - 2192-2640 .- 2192-2659. ; 11:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Laminins (LNs) are key components in the extracellular matrix of neuronal tissues in the developing brain and neural stem cell niches. LN-presenting hydrogels can provide a biologically relevant matrix for the 3D culture of neurons toward development of advanced tissue models and cell-based therapies for the treatment of neurological disorders. Biologically derived hydrogels are rich in fragmented LN and are poorly defined concerning composition, which hampers clinical translation. Engineered hydrogels require elaborate and often cytotoxic chemistries for cross-linking and LN conjugation and provide limited possibilities to tailor the properties of the materials. Here a modular hydrogel system for neural 3D cell cultures, based on hyaluronan and poly(ethylene glycol), that is cross-linked and functionalized with human recombinant LN-521 using bioorthogonal copper-free click chemistry, is shown. Encapsulated human neuroblastoma cells demonstrate high viability and grow into spheroids. Long-term neuroepithelial stem cells (lt-NES) cultured in the hydrogels can undergo spontaneous differentiation to neural fate and demonstrate significantly higher viability than cells cultured without LN. The hydrogels further support the structural integrity of 3D bioprinted structures and maintain high viability of bioprinted and syringe extruded lt-NES, which can facilitate biofabrication and development of cell-based therapies.
  •  
24.
  • Jury, Michael, 1984- (författare)
  • Modular Hyaluronan-Based Hydrogels for 3D Cell Culture and Bioprinting
  • 2022
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Three-dimensional (3D) cell culture facilitates development of biological relevant assays for drug screening and toxicity testing. Compared to conventional 2D cell culture, cells cultured in 3D can more accurately mimic human tissues and organs and thus provide ex vivo data with potentially better predictive value for cancer research, pharmacology, and toxicology, reducing the need for animal models, improving experimental reproducibility, and reducing time and costs in drug development. The most widely used options for scaffold-based 3D cell culture are, however, based on poorly defined biologically derived extracellular matrix (ECM) with limited possibilities to tailor material properties and that are difficult to combine with state-of-the art biofabrication techniques.   The overall aim this thesis was to design and explore modular hyaluronan (HA) based ECM-mimicking hydrogels with tuneable physiochemical properties and biofunctionalities, for development of advanced 3D cell models and biofabrication. The thesis work is presented in five papers. In paper I, we used copper free click chemistry for both hydrogel cross-linking and functionalization with fibronectin derived peptide sequences for culture of human induced pluripotent-derived hepatocytes in a perfused microfluidic system. The tuneable and bioorthogonal cross-linking enabled both retention of high cell viabilities and fabrication of a functional liver-on-chip solution. In paper II, we combined the developed HA-based hydrogel system with homo- and heterodimerizing helix-loop-helix peptides for modulation of both cross-linking density and biofunctionalization. We further demonstrated the possibilities to use these hydrogels as bioinks for 3D bioprinting where both the molecular composition and the physical properties of the printed structures could be dynamically altered, providing new avenues for four-dimensional (4D) bioprinting. In paper III we investigated the possibilities to chemically conjugate full size recombinant human laminin-521 (LN521) in the HA-based hydrogels system using copper-free click chemistry, with the aim to enable 3D culture and 3D bioprinting of neurons. We quantified the impact of using different linkers to tether LN521 and the influence of LN-functionalization on the structural and mechanical properties of the hydrogels. We show that both differentiated and non-differentiated neuroblastoma cells and long-term self-renewing neuroepithelial stem cells (lt-NES) remained viable in the hydrogels. The hydrogels also had a protected effect on lt-NES during syringe ejection and bioprinting. In paper IV, we used HA-based hydrogels modified with peptides sequences derived from fibronectin and laminin for culture of fetal primary astrocytes (FPA). We explored both the interactions between the hydrogels and FPA and possibilities to 3D bioprint FPAs.  Finally, in paper V, we developed HA-nanocellulose composite hydrogels with the aim to increase printing fidelity and enable fabrication of multi-layered bioprinted structures without the use of a support bath. In addition to HA, we used wood-fibre derived nanocellulose (NC) to increase the viscosity of the bioink during the printing process.  The developed biorthogonal and modular hydrogel systems provide a large degree of flexibility that allows for encapsulation and culture of different cell types and processing using different techniques, which can contribute to further exploration of fabrication of biologically relevant tissue and disease models.   
  •  
25.
  • Koon Lim, Seng, et al. (författare)
  • Tuning Liposome Membrane Permeability by Competitive Peptide Dimerization and Partitioning-Folding Interactions Regulated by Proteolytic Activity
  • 2016
  • Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 6:21123, s. 1-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Membrane active peptides are of large interest for development of drug delivery vehicles and therapeutics for treatment of multiple drug resistant infections. Lack of specificity can be detrimental and finding routes to tune specificity and activity of membrane active peptides is vital for improving their therapeutic efficacy and minimize harmful side effects. We describe a de novo designed membrane active peptide that partition into lipid membranes only when specifically and covalently anchored to the membrane, resulting in pore-formation. Dimerization with a complementary peptide efficiently inhibits formation of pores. The effect can be regulated by proteolytic digestion of the inhibitory peptide by the matrix metalloproteinase MMP-7, an enzyme upregulated in many malignant tumors. This system thus provides a precise and specific route for tuning the permeability of lipid membranes and a novel strategy for development of recognition based membrane active peptides and indirect enzymatically controlled release of liposomal cargo.
  •  
26.
  • Mak, Wing Cheung, et al. (författare)
  • Probing Zinc-Protein-Chelant Interactions using Gold Nanoparticles Functionalized with Zinc-Responsive Polypeptides
  • 2014
  • Ingår i: Particle & particle systems characterization. - : Wiley-VCH Verlagsgesellschaft. - 0934-0866 .- 1521-4117. ; 31:11, s. 1127-1133
  • Tidskriftsartikel (refereegranskat)abstract
    • The coordination of zinc by proteins and various other organic molecules is essential for numerous biological processes, such as in enzymatic catalysis, metabolism and signal transduction. Presence of small molecular chelants can have a profound effect on the bioavailability of zinc and affect critical Zn2+-protein interactions. Zn2+ chelators are also emerging therapeutics for Alzheimer’s diseases because of their preventive effect on zinc promoted amyloid formation. Despite the importance of zinc-protein-chelant interactions in biology and medicine, probing such interactions is  challenging. Here, we introduce an innovative approach for real-time characterization of zinc-protein-chelant interactions using gold nanoparticles (AuNPs) functionalized with a zinc-responsive protein mimetic polypeptide. The peptide functionalized AuNPs aggregate extensively in the presence of Zn2+, triggered by specific Zn2+-mediated polypeptide dimerization and folding, causing a massive red shift of the plasmon band. Chelants affects the Zn2+- polypeptide interaction and thus the aggregation differently depending on their concentrations, zincbinding affinities and coordination numbers, which affect the position of the plasmon band. This system is a simple and powerful tool that provides extensive information about the interactions of chelants in the formation of Zn2+ coordination complexes and is an interesting platform for development of bioanalytical techniques and characterization of chelation-based therapeutics.
  •  
27.
  •  
28.
  • Matthiesen, Isabelle, et al. (författare)
  • Astrocyte 3D culture and bioprinting using peptide functionalized hyaluronan hydrogels
  • 2023
  • Ingår i: Science and Technology of Advanced Materials. - : Informa UK Limited. - 1468-6996 .- 1878-5514. ; 24:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Astrocytes play an important role in the central nervous system, contributing to the development of and maintenance of synapses, recycling of neurotransmitters, and the integrity and function of the blood-brain barrier. Astrocytes are also linked to the pathophysiology of various neurodegenerative diseases. Astrocyte function and organization are tightly regulated by interactions mediated by the extracellular matrix (ECM). Engineered hydrogels can mimic key aspects of the ECM and can allow for systematic studies of ECM-related factors that govern astrocyte behaviour. In this study, we explore the interactions between neuroblastoma (SH-SY5Y) and glioblastoma (U87) cell lines and human fetal primary astrocytes (FPA) with a modular hyaluronan-based hydrogel system. Morphological analysis reveals that FPA have a higher degree of interactions with the hyaluronan-based gels compared to the cell lines. This interaction is enhanced by conjugation of cell-adhesion peptides (cRGD and IKVAV) to the hyaluronan backbone. These effects are retained and pronounced in 3D bioprinted structures. Bioprinted FPA using cRGD functionalized hyaluronan show extensive and defined protrusions and multiple connections between neighboring cells. Possibilities to tailor and optimize astrocyte-compatible ECM-mimicking hydrogels that can be processed by means of additive biofabrication can facilitate the development of advanced tissue and disease models of the central nervous system.
  •  
29.
  • Musa, Amani, 1983-, et al. (författare)
  • Plantaricin NC8 alpha beta prevents Staphylococcus aureus-mediated cytotoxicity and inflammatory responses of human keratinocytes
  • 2021
  • Ingår i: Scientific Reports. - : Nature Portfolio. - 2045-2322. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Multidrug resistance bacteria constitue an increasing global health problem and the development of novel therapeutic strategies to face this challenge is urgent. Antimicrobial peptides have been proven as potent agents against pathogenic bacteria shown by promising in vitro results. The aim of this study was to characterize the antimicrobial effects of PLNC8 alpha beta on cell signaling pathways and inflammatory responses of human keratinocytes infected with S. aureus. PLNC8 alpha beta did not affect the viability of human keratinocytes but upregulated several cytokines (IL-1 beta, IL-6, CXCL8), MMPs (MMP1, MMP2, MMP9, MMP10) and growth factors (VEGF and PDGF-AA), which are essential in cell regeneration. S. aureus induced the expression of several inflammatory mediators at the gene and protein level and PLNC8 alpha beta was able to significantly suppress these effects. Intracellular signaling events involved primarily c-Jun via JNK, c-Fos and NF kappa B, suggesting their essential role in the initiation of inflammatory responses in human keratinocytes. PLNC8 alpha beta was shown to modulate early keratinocyte responses, without affecting their viability. The peptides have high selectivity towards S. aureus and were efficient at eliminating the bacteria and counteracting their inflammatory and cytotoxic effects, alone and in combination with low concentrations of gentamicin. We propose that PLNC8 alpha beta may be developed to combat infections caused by Staphylococcus spp.
  •  
30.
  • Naeimipour, Sajjad, 1987-, et al. (författare)
  • Enzymatically Triggered Deprotection and Cross-Linking of Thiolated Alginate-Based Bioinks
  • 2022
  • Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 34:21, s. 9536-9545
  • Tidskriftsartikel (refereegranskat)abstract
    • Thiolated polymers are widely used in hydrogels for drug delivery, tissue engineering, and biofabrication. The oxidation of thiols is spontaneous, resulting in the formation of disulfide bridges and cross linking of polymers. The cross-linking process is, however, difficult to control and is initiated directly when the thiolated components are exposed to ambient conditions, which significantly complicates handling of the materials. Here, we show a fully bioorthogonal enzyme-mediated thiol-based chemistry for dynamic covalent cross-linking of carbohydrate-based hydrogels that circumvents the problems with uncontrolled thiol oxidation. Alginate was modified with cysteine residues, protected by an enzyme-labile thiol-protecting group (Phacm). Releasing the Phacm group by penicillin G acylase generates free thiols that oxidize under physiological conditions, resulting in a reversible cross-linking and formation of hydrogels with tunable stiffness. Prior to deprotection, the components can be exposed to ambient conditions. The enzyme-triggered deprotection and subsequent gelation allows for encapsulation of cells and 3D bioprinting of cell-laden hydrogel structures. Remaining deprotected thiols enabled postprinting modifications and hydrogel self-healing. The proposed hydrogel synthesis strategy significantly increases the versatility of thiol-based cross-linking chemistries and provides new possibilities to generate dynamic covalent hydrogels for a broad range of biomedical applications.
  •  
31.
  • Naeimipour, Sajjad, 1987- (författare)
  • Modular Enzyme-Responsive Polysaccharide-Based Hydrogels for Biofabrication
  • 2023
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Engineered human tissue and disease models can decrease the cost and time of developing new drugs and treatments, facilitate personalized medicine, and eliminate the need for animal models that poorly represent the human body and are ethically problematic. However, the current conventional cell expansion methods using 2D culture flasks cannot enable the development of such complex multi-cellular 3D models. In general, hydrogels are considered promising materials that can make the biofabrication of tissue models possible. Hydrogels are highly hydrated materials comprised of either synthetic or naturally derived polymers, or a combination of both, and can form an environment mimicking the biomacromolecular network surrounding cells in the body. This network of biopolymers, known as extracellular matrix (ECM), is comprised of proteins such as collagen, laminin, fibronectin, and polysaccharides such as hyaluronan (HA), heparan, keratan, and chondroitin sulfate. The design of hydrogels representing the physical and biochemical properties of the ECM and which can be used for biofabrication is challenging but of increasing interest due to the rapid progress in the development of 3D and 4D bioprinting techniques. As the ECM properties differ between various tissues and disease conditions and change over time, a dynamic modular hydrogel system is needed to that can be optimized for each cell and tissue type. This thesis aims to develop modular enzyme-responsive polysaccharide-based hydrogels for 3D cell culture and biofabrication. The natural polysaccharides, hyaluronic acid (HA) and alginate (Alg) were used as the main backbone in the hydrogels developed in this thesis. HA was modified by conjugating bicyclo[6.1.0]non-4-yne (BCN) to the backbone to form HA-BCN-based hydrogels by a bioorthogonal strain-promoted alkyne-azide cycloaddition. The click reaction between BCN and azide groups allowed for modulating the biochemical and mechanical properties of the HA-BCN hydrogels. HA-BCN was further decorated with peptides to explore peptide folding and dimerization-mediated dynamic cross-linking and biofunctionalization. This system was further used to explore possibilities to dynamically alter the properties of 3D bioprinted structures, mimicking the biomineralization process in bone tissue. In a different study, a tumor model comprising fibroblast and breast cancer cells (MCF7) was bioprinted using HA-BCN cross-linked by matrix metalloporotease (MMP) cleavable and PEG-diazide MMP-resistant cross-linkers, demonstrating the synergistic relationship between hydrogel degradability and cancer cell growth, intensified by the presence of fibroblasts. The possibility of incorporating a conductive module into this hydrogel system was explored using the enzyme-assisted polymerization of ETE-S to form an interpenetrating conductive network inside HA-BCN hydrogel. The in situ and user-triggered polymerization of conductive ETE-S was demonstrated after 3D printing HA-BCN bioink containing ETE-S monomers into a lattice shape structure. We also demonstrated that cellulose nanofibrils (CNF) improved the printability of HA-BCN bioinks, and this hybrid bioink was used for printing self-standing cell-laden 3D structures. Besides these studies, a novel enzymatically triggered thiol-based chemistry was developed to address the unwanted oxidation of thiol-containing hydrogels and decrease the off-target thiol reactions during hydrogel synthesis and formation. Alginate containing sulfhydryl moieties, protected by an enzyme-labile Phacm group (AlgCP), was treated with penicillin G acylase and subsequently formed a disulfide cross-linked hydrogel. We studied the gelation kinetics and rheological properties of AlgCP and different modes of cross-linking by reversible disulfide bonds, a thiol-maleimide Micheale-type addition reaction, and ionic interactions between alginate and Ca2+ ions. MCF7 breast cancer cells cultured in the AlgCP hydrogels formed spheroids that could be harvested by GSH dissolution of the hydrogels. Finally, this novel chemistry enabled bioprinting of multi-material 3D structures with control over the printed structure's physiochemical properties, including the type and density of cross-linkers. Bioprinted fibroblasts formed extended morphology, and MCF7 cells formed spheroids in the bioprinted lattice structures.   The hydrogel systems developed and explored in this thesis are modular and exhibit dynamic and tunable properties, and are applicable for a wide range of 3D cell culture and bioprinting applications. The hydrogels were either formed in response to the activity of an enzyme or remodeled by enzymes. Both enzyme-responsive HA-BCN and AlgCP hydrogel systems are promising bioinks for generating more elaborate and spatially defined cell-laden 3D structures whose features can be altered post-printing by cell-secreted and extrinsic reagents. These hydrogel-based toolkits can play a vital role in developing tissue and disease models that can make the drug discovery process faster, cheaper, and animal-free. 
  •  
32.
  • Naeimipour, Sajjad, et al. (författare)
  • Multimodal and dynamic cross-linking of modular thiolated alginate-based bioinks
  • 2023
  • Ingår i: Materials Today Advances. - : ELSEVIER. - 2590-0498. ; 19
  • Tidskriftsartikel (refereegranskat)abstract
    • Engineered extracellular matrix-mimicking hydrogels can facilitate 3D cell culture and fabrication of tissue-like constructs and biologically relevant disease models. Processing of cell-laden hydrogels using additive manufacturing techniques further allows for the development of tissue-mimetic structures with higher spatial complexity. Whereas a wide range of printable hydrogels is available, they tend to lack biological functionality and cell compatibility. Here we show an enzymatically mediated thiol-based cross-linking strategy for the design of modular and cytocompatible hydrogel-based bioinks for 3D bioprinting of dynamic multi-material architectures. Alginate is functionalized with cysteines modified with an enzyme-labile thiol protection group. Deprotection using penicillin G acylase (PGA) generates free thiols on-demand, enabling hydrogel cross-linking using thiol-reactive cross-linkers and intermolecular disulfides while avoiding undesired and uncontrolled thiol oxidation. Remaining free thiols can be used for post-printing hydrogel functionalization and lamination of multilayer structures. Moreover, the addition of PGA to a thermo-reversible hydrogel support bath enables the bioprinting of cell-laden 3D structures with high cell viability and excellent shape fidelity. The possibilities to enzymatically generate free thiols during bioprinting facilitate cross-linking and tuning of bioink properties using cytocompatible chemistries and allow for the printing of complex and dynamic cell-laden structures.
  •  
33.
  • Omer, Abubakr A. M., 1982-, et al. (författare)
  • Plantaricin NC8 αβ rapidly and efficiently inhibits flaviviruses and SARS-CoV-2 by disrupting their envelopes
  • 2022
  • Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 17:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Potent broad-spectrum antiviral agents are urgently needed to combat existing and emerging viral infections. This is particularly important considering that vaccine development is a costly and time consuming process and that viruses constantly mutate and render the vaccine ineffective. Antimicrobial peptides (AMP), such as bacteriocins, are attractive candidates as antiviral agents against enveloped viruses. One of these bacteriocins is PLNC8 αβ, which consists of amphipathic peptides with positive net charges that display high affinity for negatively charged pathogen membrane structures, including phosphatidylserine rich lipid membranes of viral envelopes. Due to the morphological and physiological differences between viral envelopes and host cell plasma membranes, PLNC8 αβ is thought to have high safety profile by specifically targeting viral envelopes without effecting host cell membranes. In this study, we have tested the antiviral effects of PLNC8 αβ against the flaviviruses Langat and Kunjin, coronavirus SARS-CoV-2, influenza A virus (IAV), and human immunodeficiency virus-1 (HIV-1). The concentration of PLNC8 αβ that is required to eliminate all the infective virus particles is in the range of nanomolar (nM) to micromolar (μM), which is surprisingly efficient considering the high content of cholesterol (8–35%) in their lipid envelopes. We found that viruses replicating in the endoplasmic reticulum (ER)/Golgi complex, e.g. SARS-CoV-2 and flaviviruses, are considerably more susceptible to PLNC8 αβ, compared to viruses that acquire their lipid envelope from the plasma membrane, such as IAV and HIV-1. Development of novel broad-spectrum antiviral agents can significantly benefit human health by rapidly and efficiently eliminating infectious virions and thereby limit virus dissemination and spreading between individuals. PLNC8 αβ can potentially be developed into an effective and safe antiviral agent that targets the lipid compartments of viral envelopes of extracellular virions, more or less independent of virus antigenic mutations, which faces many antiviral drugs and vaccines.
  •  
34.
  • Palomar, Quentin, 1991-, et al. (författare)
  • Peptide Decorated Gold Nanoparticle/Carbon Nanotube Electrochemical Sensor for Ultrasensitive Detection of Matrix Metalloproteinase-7
  • 2020
  • Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 325
  • Tidskriftsartikel (refereegranskat)abstract
    • Matrix Metalloproteinase-7 (MMP-7) is a proteolytic enzyme overexpressed in different pathological conditions, including cancer, infection, and cardiovascular diseases, and is a relevant diagnostic biomarker and potential drug target. Here we demonstrate rapid and selective detection of MMP-7 with a limit-of-detection of 6 pg/mL and a dynamic range from 1 × 10−2 to 1 × 103 ng/mL using a peptide decorated gold nanoparticle/carbon nanotube electrochemical sensor. The sensor could be operated in diluted human serum and synthetic urine, with high specificity towards MMP-7. Moreover, the integration of nanomaterials in the sensing electrode significantly increased the signal-to-background ratio and strongly improved the stability of the sensor when compared to a conventional gold electrode. The simple and cost-effective fabrication and the ease of use make this sensor a very promising protease detection device for diagnostics and drug development.
  •  
35.
  • Rasti Boroojeni, Fatemeh, et al. (författare)
  • Proteolytic remodeling of 3D bioprinted tumor microenvironments
  • 2024
  • Ingår i: Biofabrication. - : IOP Publishing Ltd. - 1758-5082 .- 1758-5090. ; 16:2
  • Tidskriftsartikel (refereegranskat)abstract
    • In native tissue, remodeling of the pericellular space is essential for cellular activities and is mediated by tightly regulated proteases. Protease activity is dysregulated in many diseases, including many forms of cancer. Increased proteolytic activity is directly linked to tumor invasion into stroma, metastasis, and angiogenesis as well as all other hallmarks of cancer. Here we show a strategy for 3D bioprinting of breast cancer models using well-defined protease degradable hydrogels that can facilitate exploration of the multifaceted roles of proteolytic extracellular matrix remodeling in tumor progression. We designed a set of bicyclo[6.1.0]nonyne functionalized hyaluronan (HA)-based bioinks cross-linked by azide-modified poly(ethylene glycol) (PEG) or matrix metalloproteinase (MMP) degradable azide-functionalized peptides. Bioprinted structures combining PEG and peptide-based hydrogels were proteolytically degraded with spatial selectivity, leaving non-degradable features intact. Bioprinting of tumor-mimicking microenvironments using bioinks comprising human breast cancer cells (MCF-7) and fibroblast in hydrogels with different susceptibilities to proteolytic degradation shows that MCF-7 proliferation and spheroid size were significantly increased in protease degradable hydrogel compartments, but only in the presence of fibroblasts. In the absence of fibroblasts in the stromal compartment, cancer cell proliferation was reduced and did not differ between degradable and nondegradable hydrogels. The interactions between spatially separated fibroblasts and MCF-7 cells consequently resulted in protease-mediated remodeling of the bioprinted structures and a significant increase in cancer cell spheroid size, highlighting the close interplay between cancer cells and stromal cells in the tumor microenvironment and the influence of proteases in tumor progression.
  •  
36.
  • Rouhbakhsh, Zeinab, et al. (författare)
  • Self-Assembly of a Structurally Defined Chiro-Optical Peptide-Oligothiophene Hybrid Material
  • 2018
  • Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 3:11, s. 15066-15075
  • Tidskriftsartikel (refereegranskat)abstract
    • Conducting polymers are routinely used in optoelectronic biomaterials, but large polymer polydispersity and poor aqueous compatibility complicate integration with biomolecular templates and development of discrete and defined supramolecular complexes. Herein, we report on a chiro-optical hybrid material generated by the self-assembly of an anionic peptide and a chemically defined cationic pentameric thiophene in aqueous environment. The peptide acts as a stereochemical template for the thiophene and adopts an α-helical conformation upon association, inducing optical activity in the thiophene π-π* transition region. Theoretical calculations confirm the experimentally observed induced structural changes and indicate the importance of electrostatic interactions in the complex. The association process is also probed at the substrate-solvent interface using peptide-functionalized gold nanoparticles, indicating that the peptide can also act as a scaffold when immobilized, resulting in structurally well-defined supramolecular complexes. The hybrid complex could rapidly be assembled, and the kinetics of the formation could be monitored by utilizing the local surface plasmon resonance originating from the gold nanoparticles. We foresee that these findings will aid in designing novel hybrid materials and provide a possible route for the development of functional optoelectronic interfaces for both biomaterials and energy harvesting applications.
  •  
37.
  • Selegård, Robert, et al. (författare)
  • Distinct Electrostatic Interactions Govern the Chiro-Optical Properties and Architectural Arrangement of Peptide-Oligothiophene Hybrid Materials
  • 2017
  • Ingår i: Macromolecules. - : AMER CHEMICAL SOC. - 0024-9297 .- 1520-5835. ; 50:18, s. 7102-7110
  • Tidskriftsartikel (refereegranskat)abstract
    • The development of chiral optoelectronic materials is of great interest due to their potential of being utilized in electronic devices, biosensors, and artificial enzymes. Herein, we report the chiral optical properties and architectural arrangement of optoelectronic materials generated from noncovalent self-assembly of a cationic synthetic peptide and five chemically defined anionic pentameric oligothiophenes. The peptide-oligothiophene hybrid materials exhibit a three-dimensional ordered helical structure and optical activity in the pi-pi* transition region that are observed due to a single chain induced chirality of the conjugated thiophene backbone upon interaction with the peptide. The latter property is highly dependent on electrostatic interactions between the peptide and the oligothiophene, verifying that a distinct spacing of the carboxyl groups along the thiophene backbone is a major chemical determinant for having a hybrid material with distinct optoelectronic properties. The necessity of the electrostatic interaction between specific carboxyl functionalities along the thiophene backbone and the lysine residues of the peptide, as well as the induced circular dichroism of the thiophene backbone, was also confirmed by theoretical calculations. We foresee that our findings will aid in designing optoelectronic materials with dynamic architectonical precisions as well as offer the possibility to create the next generation of materials for organic electronics and organic bioelectronics.
  •  
38.
  • Selegård, Robert, et al. (författare)
  • Folding driven self-assembly of a stimuli-responsive peptide-hyaluronan hybrid hydrogel
  • 2017
  • Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Protein-metal ion interactions are ubiquitous in nature and can be utilized for controlling the self-assembly of complex supramolecular architectures and materials. Here, a tunable supramolecular hydrogel is described, obtained by self-assembly of a Zn2+-responsive peptide-hyaluronic acid hybrid synthesized using strain promoted click chemistry. Addition of Zn2+ triggers folding of the peptides into a helix-loop-helix motif and dimerization into four-helix bundles, resulting in hydrogelation. Removal of the Zn2+ by chelators results in rapid hydrogel disassembly. Degradation of the hydrogels can also be time-programed by encapsulation of a hydrolyzing enzyme within the gel, offering multiple possibilities for modulating materials properties and release of encapsulated species. The hydrogel further shows potential antioxidant properties when evaluated using an in vitro model for reactive oxygen species.
  •  
39.
  • Selegård, Robert, et al. (författare)
  • Generic Phosphatase Activity Detection using Zinc Mediated Aggregation Modulation of Polypeptide-Modified Gold Nanoparticles
  • 2014
  • Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 6:23, s. 14204-14212
  • Tidskriftsartikel (refereegranskat)abstract
    • A challenge in the design of plasmonic nanoparticle-based colorimetric assays is that the change in colloidal stability, which generates the colorimetric response, is often directly linked to the biomolecular recognition event. New assay strategies are hence required for every type of substrate and enzyme of interest. Here, a generic strategy for monitoring of phosphatase activity is presented where substrate recognition is completely decoupled from the nanoparticle stability modulation mechanism, which enables detection of a wide range of enzymes using different natural substrates with a single simple detection scheme. Phosphatase activity generates inorganic phosphate that forms an insoluble complex with Zn2+. In a sample containing a preset concentration of Zn2+, phosphatase activity will markedly reduce the concentration of dissolved Zn2+ from the original value, which in turn affects the aggregation of gold nanoparticles functionalized with a designed Zn2+ responsive polypeptide. The change in nanoparticle stability thus provides a rapid and sensitive readout of the phosphatase activity. The assay is not limited to a particular enzyme or enzyme substrate, which is demonstrated using three completely different phosphatases and five different substrates, and thus constitutes a highly interesting system for drug screening and diagnostics.
  •  
40.
  • Selegård, Robert, et al. (författare)
  • Plantaricins markedly enhance the effects of traditional antibiotics against Staphylococcus epidermidis
  • 2019
  • Ingår i: Future Microbiology. - : Future Medicine. - 1746-0913 .- 1746-0921. ; 14:3, s. 195-206
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: Bacteriocins are considered as promising alternatives to antibiotics against infections. In this study, the plantaricins (Pln) A, E, F, J and K were investigated for their antimicrobial activity against Staphylococcus epidermidis.MATERIALS & METHODS: The effects on membrane integrity were studied using liposomes and viable bacteria, respectively.RESULTS: We show that PlnEF and PlnJK caused rapid and significant lysis of S. epidermidis, and induced lysis of liposomes. The PlnEF and PlnJK displayed similar mechanisms by targeting and disrupting the bacterial cell membrane. Interestingly, Pln enhanced the effects of different antibiotics by 30- to 500-fold.CONCLUSION: This study shows that Pln in combination with low concentrations of antibiotics is efficient against S. epidermidis and may be developed as potential treatment of infections.
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41.
  • Sengupta, Anirban, et al. (författare)
  • Intranasal Coronavirus SARS-CoV-2 Immunization with Lipid Adjuvants Provides Systemic and Mucosal Immune Response against SARS-CoV-2 S1 Spike and Nucleocapsid Protein
  • 2022
  • Ingår i: Vaccines. - Basel, Switzerland : MDPI. - 2076-393X. ; 10:4
  • Tidskriftsartikel (refereegranskat)abstract
    • In this preclinical two-dose mucosal immunization study, using a combination of S1 spike and nucleocapsid proteins with cationic (N3)/or anionic (L3) lipids were investigated using an intranasal delivery route. The study showed that nasal administration of low amounts of antigens/adjuvants induced a primary and secondary immune response in systemic IgG, mIL-5, and IFN-gamma secreting T lymphocytes, as well as humoral IgA in nasal and intestinal mucosal compartments. It is believed that recipients will benefit from receiving a combination of viral antigens in promoting a border immune response against present and evolving contagious viruses. Lipid adjuvants demonstrated an enhanced response in the vaccine effect. This was seen in the significant immunogenicity effect when using the cationic lipid N3. Unlike L3, which showed a recognizable effect when administrated at a slightly higher concentration. Moreover, the findings of the study proved the efficiency of an intranasally mucosal immunization strategy, which can be less painful and more effective in enhancing the respiratory tract immunity against respiratory infectious diseases.
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42.
  • Skyttner, Camilla, et al. (författare)
  • Sequence and length optimization of membrane active coiled coils for triggered liposome release
  • 2019
  • Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : ELSEVIER SCIENCE BV. - 0005-2736 .- 1879-2642. ; 1862:2, s. 449-456
  • Tidskriftsartikel (refereegranskat)abstract
    • Defined and tunable peptide-lipid membrane interactions that trigger the release of liposome encapsulated drugs may offer a route to improving the efficiency and specificity of liposome-based drug delivery systems, but this require means to tailor the performance of the membrane active peptides. In this paper, the membrane activity of a de novo designed coiled coil peptide has been optimized with respect to sequence and size to improve release efficiency of liposome encapsulated cargo. The peptides were only membrane active when covalently conjugated to the liposomes. Two amino acid substitutions were made to enhance the amphipathic characteristics of the peptide, which increased the release by a factor of five at 1 mu M. Moreover, the effect of peptide length was investigated by varying the number of heptad repeats from 2 to 5, yielding the peptides KVC2-KVC5. The shortest peptide (KVC2) showed the least interaction with the membrane and proved less efficient than the longer peptides in releasing the liposomal cargo. The peptide with three heptads (KVC3) caused liposome aggregation whereas KVC4 proved to effectively release the liposomal cargo without causing aggregation. The longest peptide (KVC5) demonstrated the most defined a-helical secondary structure and the highest liposome surface concentration but showed slower release kinetics than KVC4. The four heptad peptide KVC4 consequently displayed optimal properties for triggering the release and is an interesting candidate for further development of bioresponsive and tunable liposomal drug delivery systems.
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43.
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44.
  • Träger, Andrea, et al. (författare)
  • Nanocellulose Reinforced Hyaluronan-Based Bioinks
  • 2023
  • Ingår i: Biomacromolecules. - : AMER CHEMICAL SOC. - 1525-7797 .- 1526-4602. ; 24:7, s. 3086-3093
  • Tidskriftsartikel (refereegranskat)abstract
    • Bioprinting of hydrogel-based bioinks can allow for thefabricationof elaborate, cell-laden 3D structures. In addition to providing anadequate extracellular matrix mimetic environment and high cell viability,the hydrogels must offer facile extrusion through the printing nozzleand retain the shape of the printed structure. We demonstrate a strategyto incorporate cellulose oxalate nanofibrils in hyaluronan-based hydrogelsto generate shear thinning bioinks that allowed for printing of free-standingmultilayer structures, covalently cross-linked after bioprinting,yielding long-term stability. The storage modulus of the hydrogelswas tunable between 0.5 and 1.5 kPa. The nanocellulose containinghydrogels showed good biocompatibility, with viability of primaryhuman dermal fibroblasts above 80% at day 7 after seeding. The cellswere also shown to tolerate the printing process well, with viabilityabove 80% 24 h after printing. We anticipate that this hydrogel systemcan find broad use as a bioink to produce complex geometries thatcan support cell growth.
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45.
  • Utterström, Johanna, et al. (författare)
  • Coiled coil-based therapeutics and drug delivery systems
  • 2021
  • Ingår i: Advanced Drug Delivery Reviews. - : Elsevier. - 0169-409X .- 1872-8294. ; 170, s. 26-43
  • Forskningsöversikt (refereegranskat)abstract
    • Coiled coils are characterized by an arrangement of two or more alpha-helices into a superhelix and one of few protein motifs where the sequence-to-structure relationship to a large extent have been decoded and understood. The abundance of both natural and de novo designed coil coils provides a rich molecular toolbox for self assembly of elaborate bespoke molecular architectures, nanostructures, and materials. Leveraging on the numerous possibilities to tune both affinities and preferences for polypeptide oligomerization, coiled coils offer unique possibilities to design modular and dynamic assemblies that can respond in a predictable manner to biomolecular interactions and subtle physicochemical cues. In this review, strategies to use coiled coils in design of novel therapeutics and advanced drug delivery systems are discussed. The applications of coiled coils for generating drug carriers and vaccines, and various aspects of using coiled coils for controlling and triggering drug release, and for improving drug targeting and drug uptake are described. The plethora of innovative coiled coil-based molecular systems provide new knowledge and techniques for improving efficacy of existing drugs and can facilitate development of novel therapeutic strategies. (c) 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/). 1. Introduction 27 2. The coiled coil motif 27 3. Coiled coils and coiled coil-hybrids for drug delivery and therapeutics 30 3.1. Coiled coils in liposome drug delivery systems 30 3.2. Lipidated coiled coils for assembly of virus-like particles 31 3.3. Coiled coil nanoparticles 31 3.4. Coiled coil nanocarriers 33 3.5. Coiled coil polymer-hybrids 33 3.6. Coiled coil-based hydrogels 36 3.7. Coiled coil inorganic nanoparticle hybrids 37 3.8. Coiled coils combined with cell penetrating peptides 37 3.9. Coiled coils for improved targeting 38
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46.
  • Utterström, Johanna, 1993- (författare)
  • Design and Optimization of Membrane Active Peptides and Lipid Vesicles for Triggered Release
  • 2024
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Liposomes can reduce toxic side effects and improve the efficacy of drugs and several liposome-based drug formulations are approved for clinical use. The therapeutic effect is dependent on the bioavailability of the drug and a slow drug release from liposomes can reduce their efficacy. Multiple strategies have been proposed to control the release of drugs from liposomes using both external stimuli such as light, heat and ultrasound, and endogenous factors such as changes in pH or enzymatic activity. However, because of the difficulties to efficiently modulate lipid membrane permeability and the challenges to trigger drug release in the target tissue, no stimuli responsive liposomes have so far been approved. There is consequently a great need for new means to tune lipid membrane integrity for liposome cargo release to improve the development of new advanced drug delivery systems for better and safer treatment of patients.  The aim of this thesis was to design and explore synthetic membrane active peptides for triggered release from liposomes and to expand the knowledge on how peptide-lipid conjugation strategies and lipid properties affect the membrane activity of the peptides. This work was based on two different de novo designed cationic and amphipathic, conjugation-dependent membrane active peptides (CKV4 and JR2KC). Both peptides fold and adopt α-helical structures upon conjugation to liposomes, triggering lipid membrane destabilization. Addition of cholesterol in the lipid membrane greatly enhanced the release efficiency of JR2KC due to a peptide-triggered lipid phase separation, resulting in domains with high local peptide concentrations. Additionally, both peptide surface concentrations and lipid net charge were found to be important factors for efficient release. However, when the zeta potential decreased below -75 mV, conjugation-independent release mechanisms were triggered. Liposome size was shown to only have minor effects on the release kinetics for both sets of peptides while a mixture of saturated and unsaturated lipids was beneficial for the peptide-triggered membrane destabilization, possibly due to increased propensity for lipid phase separation.  In addition to changing lipid properties, peptide-lipid conjugation strategies proved to highly affect the release kinetics, where the Michael addition reaction between a cysteine in the peptide and maleimide-lipids was much more efficient in causing peptide-triggered membrane destabilization than strain-promoted alkyne azide cycloaddition reactions using azide-modified peptides and DBCO-functionalized lipids. However, thiols tend to oxidize under ambient conditions which complicates peptide-lipid conjugation. This was addressed by synthesizing a peptide with a cysteine modified with an enzyme labile thiol protection group. Enzymatic deprotection allowed efficient peptide-lipid conjugation, reducing the risk of peptide oxidation.  To further find means to tailor peptide-lipid interactions, we explored the effect of a competing peptide heterodimerization process on lipid membrane destabilization. Addition of a charge complementary peptide to CKV4 resulted in heterodimerization and folding into a coiled coil, which inhibited its membrane activity. However, when the two peptides were synthesized as a single sequence, the membrane activity was altered, most likely due to the induced preorganization increasing membrane affinity. The results presented in this thesis provide new understandings of the complex peptide-lipid interactions that govern peptide-induced release from liposomes and will facilitate further optimization in peptide design for the future development of advanced liposome-based drug delivery systems. 
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47.
  • Utterström, Johanna, et al. (författare)
  • Peptide-Folding Triggered Phase Separation and Lipid Membrane Destabilization in Cholesterol-Rich Lipid Vesicles
  • 2022
  • Ingår i: Bioconjugate chemistry. - : AMER CHEMICAL SOC. - 1043-1802 .- 1520-4812. ; 33:4, s. 736-746
  • Tidskriftsartikel (refereegranskat)abstract
    • Liposome-based drug delivery systems are widely used to improve drug pharmacokinetics but can suffer from slow and unspecific release of encapsulated drugs. Membrane-active peptides, based on sequences derived or inspired from antimicrobial peptides (AMPs), could offer means to trigger and control the release. Cholesterol is used in most liposomal drug delivery systems (DDS) to improve the stability of the formulation, but the activity of AMPs on cholesterol-rich membranes tends to be very low, complicating peptide-triggered release strategies. Here, we show a de novo designed AMP-mimetic peptide that efficiently triggers content release from cholesterol-containing lipid vesicles when covalently conjugated to headgroup-functionalized lipids. Binding to vesicles induces peptide folding and triggers a lipid phase separation, which in the presence of cholesterol results in high local peptide concentrations at the lipid bilayer surface and rapid content release. We anticipate that these results will facilitate the development of peptide-based strategies for controlling and triggering drug release from liposomal drug delivery systems.
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48.
  • Wang, Yusong, et al. (författare)
  • Specific functionalization of CTAB stabilized anisotropic gold nanoparticles with polypeptides for folding-mediated self-assembly
  • 2012
  • Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry. - 0959-9428 .- 1364-5501. ; 22:38, s. 20368-20373
  • Tidskriftsartikel (refereegranskat)abstract
    • Anisotropic nanoparticles stabilized by cetyltrimethylammonium bromide (CTAB) are notoriously difficult to homogenously functionalize using conventional gold-thiol chemistry. Using surface assisted laser desorption time of flight mass spectroscopy and scanning transmission electron microscopy-energy dispersive X-ray spectroscopy, we demonstrate that silver species adsorbed on the particle surface prevent effective surface functionalization. When covered by a thin gold film, particle functionalization was drastically improved. A thiol-containing polypeptide was immobilized on arrowhead gold nanorods (NRs) and was subsequently able to selectively heteroassociate with a complementary polypeptide resulting in a folding-mediated bridging aggregation of the NRs. Despite using arrowhead NRs with a pronounced difference in surface arrangement on the {111} facets on the arrowheads compared to the {100} facets at the particle sides, the polypeptides were efficiently and homogeneously immobilized on the particles after gold film overgrowth.
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49.
  • Wiman, Emanuel, 1985-, et al. (författare)
  • Development of novel broad-spectrum antimicrobial lipopeptides derived from plantaricin NC8 β
  • 2023
  • Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Bacterial resistance towards antibiotics is a major global health issue. Very few novel antimicrobial agents and therapies have been made available for clinical use during the past decades, despite an increasing need. Antimicrobial peptides have been intensely studied, many of which have shown great promise in vitro. We have previously demonstrated that the bacteriocin Plantaricin NC8 αβ (PLNC8 αβ) from Lactobacillus plantarum effectively inhibits Staphylococcus spp., and shows little to no cytotoxicity towards human keratinocytes. However, due to its limitations in inhibiting gram-negative species, the aim of the present study was to identify novel antimicrobial peptidomimetic compounds with an enhanced spectrum of activity, derived from the β peptide of PLNC8 αβ. We have rationally designed and synthesized a small library of lipopeptides with significantly improved antimicrobial activity towards both gram-positive and gram-negative bacteria, including the ESKAPE pathogens. The lipopeptides consist of 16 amino acids with a terminal fatty acid chain and assemble into micelles that effectively inhibit and kill bacteria by permeabilizing their cell membranes. They demonstrate low hemolytic activity and liposome model systems further confirm selectivity for bacterial lipid membranes. The combination of lipopeptides with different antibiotics enhanced the effects in a synergistic or additive manner. Our data suggest that the novel lipopeptides are promising as future antimicrobial agents, however additional experiments using relevant animal models are necessary to further validate their in vivo efficacy.
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50.
  • Zeng, Shuangshuang, et al. (författare)
  • Mechanism and kinetics of lipid bilayer formation in solid-state nanopores
  • 2020
  • Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 36:6, s. 1446-1453
  • Tidskriftsartikel (refereegranskat)abstract
    • Solid-state nanopores provide a highly versatile platform for rapid electrical detection and analysis of single molecules. Lipid bilayer coating of the nanopores can reduce nonspecific analyte adsorption to the nanopore sidewalls and increase the sensing selectivity by providing possibilities for tethering specific ligands in a cell-membrane mimicking environment. However, the mechanism and kinetics of lipid bilayer formation from vesicles remain unclear in the presence of nanopores. In this work, we used a silicon-based, truncated pyramidal nanopore array as the support for lipid bilayer formation. Lipid bilayer formation in the nanopores was monitored in real time by the change in ionic current through the nanopores. Statistical analysis revealed that a lipid bilayer is formed from the instantaneous rupture of individual vesicle upon adsorption in the nanopores, differing from the generally agreed mechanism that lipid bilayer forms at a high vesicle surface coverage on a planar support. The dependence of the lipid bilayer formation process on the applied bias, vesicle size, and concentration was systematically studied. In addition, the nonfouling properties of the lipid bilayer coated nanopores were demonstrated during long single-stranded DNA translocation through the nanopore array. The findings indicate that the lipid bilayer formation process can be modulated by introducing nanocavities intentionally on the planar surface to create active sites or changing the vesicle size and concentration.
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