| 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.
|
|
| 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).
|
|
| 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.
|
|
| 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.
|
|
| 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.
|
|
| 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.
|
|
| 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.
|
|
| 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.
|
|
| 9. |
|
|
| 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.
|
|
