| 141. |
- Sedlacek, Ondrej, et al.
(författare)
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Influence of Chain Length of Gradient and Block Copoly(2-oxazoline)s on Self-Assembly and Drug Encapsulation
- 2022
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Ingår i: Small. - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 18:17
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Tidskriftsartikel (refereegranskat)abstract
- Amphiphilic gradient copolymers represent a promising alternative to extensively used block copolymers due to their facile one-step synthesis by statistical copolymerization of monomers of different reactivity. Herein, an in-depth analysis is provided of micelles based on amphiphilic gradient poly(2-oxazoline)s with different chain lengths to evaluate their potential for micellar drug delivery systems and compare them to the analogous diblock copolymer micelles. Size, morphology, and stability of self-assembled nanoparticles, loading of hydrophobic drug curcumin, as well as cytotoxicities of the prepared nanoformulations are examined using copoly(2-oxazoline)s with varying chain lengths and comonomer ratios. In addition to several interesting differences between the two copolymer architecture classes, such as more compact self-assembled structures with faster exchange dynamics for the gradient copolymers, it is concluded that gradient copolymers provide stable curcumin nanoformulations with comparable drug loadings to block copolymer systems and benefit from more straightforward copolymer synthesis. The study demonstrates the potential of amphiphilic gradient copolymers as a versatile platform for the synthesis of new polymer therapeutics.
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| 142. |
- Sekula, Sylwia, et al.
(författare)
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Multiplexed Lipid Dip-Pen Nanolithography on Subcellular Scales for the Templating of Functional Proteins and Cell Culture
- 2008
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Ingår i: Small. - : Wiley. - 1613-6829 .- 1613-6810. ; 4:10, s. 1785-1793
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Tidskriftsartikel (refereegranskat)abstract
- Molecular patterning processes taking place in biological systems are challenging to study in vivo because of their dynamic behavior, subcellular size, and high degree of complexity. In vitro patterning of biomolecules using nanolithography allows simplification of the processes and detailed study of the dynamic interactions. Parallel dip-pen nanolithography (DPN) is uniquely capable of integrating functional biomolecules on subcellular length scales due to its constructive nature, high resolution, and high throughput. Phospholipids are particularly well suited as inks for DPN since a variety of different functional lipids can be readily patterned in parallel. Here DPN is used to spatially pattern multicomponent micro- and nano-structured supported lipid membranes and multilayers that are fluid and contain various amounts of biotin and/or nitrilotriacetic acid functional groups. The patterns are characterized by fluorescence microscopy and photoemission electron microscopy. Selective adsorption of functionalized or recombinant proteins based on streptavidin or histidine-tag coupling enables the semisynthetic fabrication of model peripheral membrane bound proteins. The biomimetic membrane patterns formed in this way are then used as substrates for cell culture, as demonstrated by the selective adhesion and activation of T-cells.
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| 143. |
- Seufert, Laura, et al.
(författare)
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Stretchable Tissue-Like Gold Nanowire Composites with Long-Term Stability for Neural Interfaces
- 2024
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Ingår i: Small. - : John Wiley and Sons Inc. - 1613-6810 .- 1613-6829.
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Tidskriftsartikel (refereegranskat)abstract
- Soft and stretchable nanocomposites can match the mechanical properties of neural tissue, thereby minimizing foreign body reactions to provide optimal stimulation and recording specificity. Soft materials for neural interfaces should simultaneously fulfill a wide range of requirements, including low Young’s modulus (<<1 MPa), stretchability (≥30%), high conductivity (>> 1000 S cm−1), biocompatibility, and chronic stability (>> 1 year). Current nanocomposites do not fulfill the above requirements, in particular not the combination of softness and high conductivity. Here, this challenge is addressed by developing a scalable and robust synthesis route based on polymeric reducing agents for smooth, high-aspect ratio gold nanowires (AuNWs) of controllable dimensions with excellent biocompatibility. AuNW-silicone composites show outstanding performance with nerve-like softness (250 kPa), high conductivity (16 000 S cm−1), and reversible stretchability. Soft multielectrode cuffs based on the composite achieve selective functional stimulation, recordings of sensory stimuli in rat sciatic nerves, and show an accelerated lifetime stability of >3 years. The scalable synthesis method provides a chemically stable alternative to the widely used AgNWs, thereby enabling new applications within electronics, biomedical devices, and electrochemistry.
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| 144. |
- Shao, Mingjiao, et al.
(författare)
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High-Performance Biodegradable Energy Storage Devices Enabled by Heterostructured MoO3-MoS2 Composites
- 2023
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Ingår i: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 19:10
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Tidskriftsartikel (refereegranskat)abstract
- Biodegradable implantable devices are of growing interest in biosensors and bioelectronics. One of the key unresolved challenges is the availability of power supply. To enable biodegradable energy-storage devices, herein, 2D heterostructured MoO3–MoS2 nanosheet arrays are synthesized on water-soluble Mo foil, showing a high areal capacitance of 164.38 mF cm−2 (at 0.5 mA cm−2). Employing the MoO3–MoS2 composite as electrodes of a symmetric supercapacitor, an asymmetric Zn-ion hybrid supercapacitor, and an Mg primary battery are demonstrated. Benefiting from the advantages of MoO3–MoS2 heterostructure, the Zn-ion hybrid supercapacitors deliver a high areal capacitance (181.86 mF cm−2 at 0.5 mA cm−2) and energy density (30.56 µWh cm−2), and the Mg primary batteries provide a stable high output voltage (≈1.6 V) and a long working life in air/liquid environment. All of the used materials exhibit desirable biocompatibility, and these fabricated devices are also fully biodegradable. Demonstration experiments display their potential applications as biodegradable power sources for various electronic devices.
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| 145. |
- Shi, F. H., et al.
(författare)
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Broadband, Spectrally Flat, Graphene-based Terahertz Modulators
- 2015
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 11:45, s. 6044-6050
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Tidskriftsartikel (refereegranskat)abstract
- Advances in the efficient manipulation of terahertz waves are crucial for the further development of terahertz technology, promising applications in many diverse areas, such as biotechnology and spectroscopy, to name just a few. Due to its exceptional electronic and optical properties, graphene is a good candidate for terahertz electro-absorption modulators. However, graphene-based modulators demonstrated to date are limited in bandwidth due to Fabry-Perot oscillations in the modulators' substrate. Here, a novel method is demonstrated to design electrically controlled graphene-based modulators that can achieve broadband and spectrally flat modulation of terahertz beams. In our design, a graphene layer is sandwiched between a dielectric and a slightly doped substrate on a metal reflector. It is shown that the spectral dependence of the electric field intensity at the graphene layer can be dramatically modified by optimizing the structural parameters of the device. In this way, the electric field intensity can be spectrally flat and even compensate for the dispersion of the graphene conductivity, resulting in almost invariant absorption in a wide frequency range. Modulation depths up to 76% can be achieved within a fractional operational bandwidth of over 55%. It is expected that our modulator designs will enable the use of terahertz technology in applications requiring broadband operation.
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| 146. |
- Shi, Mangmang, et al.
(författare)
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A Novel Aqueous Asymmetric Supercapacitor based on Pyrene-4,5,9,10-Tetraone Functionalized Graphene as the Cathode and Annealed Ti3C2Tx MXene as the Anode
- 2023
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 19, s. 2301449-
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Tidskriftsartikel (refereegranskat)abstract
- Asymmetric supercapacitors (ASCs), employing two dissimilar electrode materials with a large redox peak position difference as cathode and anode, have been designed to further broaden the voltage window and improve the energy density of supercapacitors. Organic molecule based electrodes can be constructed by combining redox-active organic molecules with conductive carbon-based materials such as graphene. Herein, pyrene-4,5,9,10-tetraone (PYT), a redox-active molecule with four carbonyl groups, exhibits a four-electron transfer process and can potentially deliver a high capacity. PYT is noncovalently combined with two different kinds of graphene (Graphenea [GN] and LayerOne [LO]) at different mass ratios. The PYT-functionalized GN electrode (PYT/GN 4–5) possesses a high capacity of 711 F g−1 at 1 A g−1 in 1 M H2SO4. To match with the PYT/GN 4–5 cathode, an annealed-Ti3C2Tx (A-Ti3C2Tx) MXene anode with a pseudocapacitive character is prepared by pyrolysis of pure Ti3C2Tx. The assembled PYT/GN 4–5//A-Ti3C2Tx ASC delivers an outstanding energy density of 18.4 Wh kg−1 at a power density of 700 W kg−1. The PYT-functionalized graphene holds great potential for high-performance energy storage devices.
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| 147. |
- Shimanovich, Ulyana, et al.
(författare)
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pH-Responsive Capsules with a Fibril Scaffold Shell Assembled from an Amyloidogenic Peptide
- 2021
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 17:26
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Tidskriftsartikel (refereegranskat)abstract
- Peptides and proteins have evolved to self-assemble into supramolecular entities through a set of non-covalent interactions. Such structures and materials provide the functional basis of life. Crucially, biomolecular assembly processes can be highly sensitive to and modulated by environmental conditions, including temperature, light, ionic strength and pH, providing the inspiration for the development of new classes of responsive functional materials based on peptide building blocks. Here, it is shown that the stimuli-responsive assembly of amyloidogenic peptide can be used as the basis of environmentally responsive microcapsules which exhibit release characteristics triggered by a change in pH. The microcapsules are biocompatible and biodegradable and may act as vehicles for controlled release of a wide range of biomolecules. Cryo-SEM images reveal the formation of a fibrillar network of the capsule interior with discrete compartments in which cargo molecules can be stored. In addition, the reversible formation of these microcapsules by modulating the solution pH is investigated and their potential application for the controlled release of encapsulated cargo molecules, including antibodies, is shown. These results suggest that the approach described here represents a promising venue for generating pH-responsive functional peptide-based materials for a wide range of potential applications for molecular encapsulation, storage, and release.
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| 148. |
- Sievers, S., et al.
(författare)
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Quantitative Measurement of the Magnetic Moment of Individual Magnetic Nanoparticles by Magnetic Force Microscopy
- 2012
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 8:17, s. 2675-2679
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Tidskriftsartikel (refereegranskat)abstract
- The quantitative measurement of the magnetization of individual magnetic nanoparticles (MNPs) using magnetic force microscopy (MFM) is described. Quantitative measurement is realized by calibration of the MFM signal using an MNP reference sample with traceably determined magnetization. A resolution of the magnetic moment of the order of 10-18 A m2 under ambient conditions is demonstrated, which is presently limited by the tip's magnetic moment and the noise level of the instrument. The calibration scheme can be applied to practically any magnetic force microscope and tip, thus allowing a wide range of future applications, for example in nanomagnetism and biotechnology.
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| 149. |
- Škrjanc, Aljaž, et al.
(författare)
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Carbonyl-Supported Coordination in Imidazolates : A Platform for Designing Porous Nickel-Based ZIFs as Heterogeneous Catalysts
- 2024
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Ingår i: Small. - 1613-6810 .- 1613-6829. ; 20:6
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Tidskriftsartikel (refereegranskat)abstract
- Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal–organic framework that have attracted considerable attention as potential functional materials due to their high chemical stability and ease of synthesis. ZIFs are usually composed of zinc ions coordinated with imidazole linkers, with some other transition metals, such as Cu(II) and Co(II), also showing potential as ZIF-forming cations. Despite the importance of nickel in catalysis, no Ni-based ZIF with permanent porosity is yet reported. It is found that the presence and arrangement of the carbonyl functional groups on the imidazole linker play a crucial role in completing the preferred octahedral coordination of nickel, revealing a promising platform for the rational design of Ni-based ZIFs for a wide range of catalytic applications. Herein, the synthesis of the first Ni-based ZIFs is reported and their high potential as heterogeneous catalysts for Suzuki–Miyaura cross-coupling C─C bond forming reactions is demonstrated.
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| 150. |
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