1,721,142 research outputs found
Compartmentalized cross-linked enzymatic nano-aggregates (c-CLEnA) for efficient in-flow biocatalysis
Full text linkNano-sized enzyme aggregates, which preserve their catalytic activity are of great interest for flow processes, as these catalytic species show minimal diffusional issues, and are still sizeable enough to be effectively separated from the formed product. The realization of such catalysts is however far from trivial. The stable formation of a micro-to millimeter-sized enzyme aggregate is feasible via the formation of a cross-linked enzyme aggregate (CLEA); however, such a process leads to a rather broad size distribution, which is not always compatible with microflow conditions. Here, we present the design of a compartmentalized templated CLEA (c-CLEnA), inside the nano-cavity of bowl-shaped polymer vesicles, coined stomatocytes. Due to the enzyme preorganization and concentration in the cavity, cross-linking could be performed with substantially lower amount of cross-linking agents, which was highly beneficial for the residual enzyme activity. Our methodology is generally applicable, as demonstrated by using two different cross-linkers (glutaraldehyde and genipin). Moreover, c-CLEnA nanoreactors were designed with Candida antarctica Lipase B (CalB) and Porcine Liver Esterase (PLE), as well as a mixture of glucose oxidase (GOx) and horseradish peroxidase (HRP). Interestingly, when genipin was used as cross-linker, all enzymes preserved their initial activity. Furthermore, as proof of principle, we demonstrated the successful implementation of different c-CLEnAs in a flow reactor in which the c-CLEnA nanoreactors retained their full catalytic function even after ten runs. Such a c-CLEnA nanoreactor represents a significant step forward in the area of in-flow biocatalysis.BT/Biocatalysi
Supramolecular hydrogels for regenerative medicine
No full textRegenerative medicine is the science of re-creating or repairing living functional tissue, often inside the body. Biomaterials for regenerative medicine are inspired by the extracellular matrix (ECM), which provides the natural scaffold for cells inside the body. The use of supramolecular hydrogels as man-made tunable replacements for the ECM is being investigated because hydrogels offer an aqueous environment. In addition, supramolecular systems offer modularity and dynamics, also found in the ECM. This chapter gives an overview of translational research on different supramolecular hydrogels, showing systems that have been used in vivo in the field of regenerative medicine. We discuss the chemical structures and biomedical applications of various natural compounds, biosynthetic compounds, biohybrid systems, and fully synthetic materials. Furthermore, we discuss tuning of the mechanical properties and functionalization of these hydrogels with bioactive compounds. Both characteristics are essential for their function in contact with cells and for the creation of a regenerative niche, thereby controlling cellular adherence, proliferation, homing, and differentiation
Entrapment of metal nanoparticles in polymer stomatocytes
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Cellular Integration of an Enzyme-Loaded Polymersome Nanoreactor
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83477.pdf (Publisher’s version ) (Open Access)4 p
Polymersome Stomatocytes: Controlled Shape Transformation in Polymer Vesicles
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84182.pdf (Publisher’s version ) (Closed access)3 p
Sortase a-mediated n-terminal modification of cowpea chlorotic mottle virus for highly efficient cargo loading
No full textA new strategy is described for the modification of CCMV for loading of cargoes inside the viral capsid. Sortase A, an enzyme which is present in Gram-positive bacteria, was used to attach cargo to the glycine-tagged N-termini of several CCMV variants. We show that small molecules and proteins bearing a C-terminal LPETG-motif can be attached in this way. This method allows for the site-specific, covalent, and orthogonal modification of CCMV capsids in a mild fashion, leading to high encapsulation efficiencies. This strategy can easily be expanded to other types of cargoes, labeled with an LPETG-tag without altering protein function
Probing morphological changes in polymersomes with magnetic birefringence
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128419.pdf (Publisher’s version ) (Open Access
Dynamic Loading and Unloading of Proteins in Polymeric Stomatocytes: Formation of an Enzyme-Loaded Supramolecular Nanomotor
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157307.pdf (Publisher’s version ) (Open Access)
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157307pre.pdf (Author’s version preprint ) (Open Access
Autonomous movement of platinum-loaded stomatocytes
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93760.pdf (Publisher’s version ) (Closed access)7 p
Hydrogen from electrochemical reforming of C1–C3 alcohols using proton conducting membranes
Full text linkThis study investigates the production of hydrogen from the electrochemical reforming of short-chain alcohols (methanol, ethanol, iso-propanol) and their mixtures. High surface gas diffusion Pt/C electrodes were interfaced to a Nafion polymeric membrane. The assembly separated the two chambers of an electrochemical reactor, which were filled with anolyte (alcohol�+�H2O or alcohol�+�H2SO4) and catholyte (H2SO4) aqueous solutions. The half-reactions, which take place upon polarization, are the alcohol electrooxidation and the hydrogen evolution reaction at the anode and cathode, respectively. A standard Ag/AgCl reference electrode was introduced for monitoring the individual anodic and cathodic overpotentials. Our results show that roughly 75% of the total potential losses are due to sluggish kinetics of the alcohol electrooxidation reaction. Anodic overpotential becomes larger as the number of C-atoms in the alcohol increases, while a slight dependence on the pH was observed upon changing the acidity of the anolyte solution. In the case of alcohol mixtures, it is the largest alcohol that dictates the overall cell performance
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