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- ItemPH-Responsive Biohybrid Carrier Material for Phenol Decontamination in Wastewater(Columbus, Ohio : American Chemical Soc., 2018) Pretscher, Martin; Pineda-Contreras, Beatriz A.; Kaiser, Patrick; Reich, Steffen; Schöbel, Judith; Kuttner, Christian; Freitag, Ruth; Fery, Andreas; Schmalz, Holger; Agarwal, SeemaSmart polymers are a valuable platform to protect and control the activity of biological agents over a wide range of conditions, such as low pH, by proper encapsulation. Such conditions are present in olive oil mill wastewater with phenol as one of the most problematic constituents. We show that elastic and pH-responsive diblock copolymer fibers are a suitable carrier for Corynebacterium glutamicum, i.e., bacteria which are known for their ability to degrade phenol. Free C. glutamicum does not survive low pH conditions and fails to degrade phenol at low pH conditions. Our tea-bag like biohybrid system, where the pH-responsive diblock copolymer acts as a protecting outer shell for the embedded bacteria, allows phenol degradation even at low pH. Utilizing a two-step encapsulation process, planktonic cells were first encapsulated in poly(vinyl alcohol) to protect the bacteria against the organic solvents used in the second step employing coaxial electrospinning.
- ItemInteraction between immobilized polyelectrolyte complex nanoparticles and human mesenchymal stromal cells(Auckland : DOVE Medical Press, 2014) Woltmann, B.; Torger, B.; Müller, M.; Hempel, U.Background: Implant loosening or deficient osseointegration is a major problem in patients with systemic bone diseases (eg, osteoporosis). For this reason, the stimulation of the regional cell population by local and sustained drug delivery at the bone/implant interface to induce the formation of a mechanical stable bone is promising. The purpose of this study was to investigate the interaction of polymer-based nanoparticles with human bone marrow-derived cells, considering nanoparticles' composition and surface net charge. Materials and methods: Polyelectrolyte complex nanoparticles (PECNPs) composed of the polycations poly(ethyleneimine) (PEI), poly(L-lysine) (PLL), or (N,N-diethylamino)ethyldextran (DEAE) in combination with the polyanions dextran sulfate (DS) or cellulose sulfate (CS) were prepared. PECNPs' physicochemical properties (size, net charge) were characterized by dynamic light scattering and particle charge detector measurements. Biocompatibility was investigated using human mesenchymal stromal cells (hMSCs) cultured on immobilized PECNP films (5-50 nmol·cm-2) by analysis for metabolic activity of hMSCs in dependence of PECNP surface concentration by MTS (3-[4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium, inner salt) assay, as well as cell morphology (phase contrast microscopy). Results: PECNPs ranging between ~50 nm and 150 nm were prepared. By varying the ratio of polycations and polyanions, PECNPs with a slightly positive (PEC+NP) or negative (PEC-NP) net charge were obtained. The PECNP composition significantly affected cell morphology and metabolic activity, whereas the net charge had a negligible influence. Therefore, we classified PECNPs into "variant systems" featuring a significant dose dependency of metabolic activity (DEAE/CS, PEI/DS) and "invariant systems" lacking such a dependency (DEAE/DS, PEI/CS). Immunofluorescence imaging of fluorescein isothiocyanate isomer I (FITC)-labeled PECNPs suggested internalization into hMSCs remaining stable for 8 days. Conclusion: Our study demonstrated that PECNP composition affects hMSC behavior. In particular, the PEI/CS system showed biocompatibility in a wide concentration range, representing a suitable system for local drug delivery from PECNP-functionalized bone substitute materials.
- ItemMatter-tag: A universal immobilization platform for enzymes on polymers, metals, and silicon-based materials(New York, NY : Wiley, 2020) Dedisch, Sarah; Wiens, Annika; Davari, Mehdi D.; Söder, Dominik; Rodriguez-Emmenegger, Cesar; Jakob, Felix; Schwaneberg, UlrichEnzyme immobilization is extensively studied to improve enzyme properties in catalysis and analytical applications. Here, we introduce a simple and versatile enzyme immobilization platform based on adhesion-promoting peptides, namely Matter-tags. Matter-tags immobilize enzymes in an oriented way as a dense monolayer. The immobilization platform was established with three adhesion-promoting peptides; Cecropin A (CecA), liquid chromatography peak I (LCI), and Tachystatin A2 (TA2), that were genetically fused to enhanced green fluorescent protein and to two industrially important enzymes: a phytase (from Yersinia mollaretii) and a cellulase (CelA2 from a metagenomic library). Here, we report a universal and simple Matter-tag–based immobilization platform for enzymes on various materials including polymers (polystyrene, polypropylene, and polyethylene terephthalate), metals (stainless steel and gold), and silicon-based materials (silicon wafer). The Matter-tag–based enzyme immobilization is performed at ambient temperature within minutes (<10 min) in an aqueous solution harboring the phytase or cellulase by immersing the targeted material. The peptide LCI was identified as universal adhesion promoter; LCI immobilized both enzymes on all investigated materials. The attachment of phytase-LCI onto gold was characterized with surface plasmon resonance spectroscopy obtaining a dissociation constant value (KD) of 2.9·10−8 M and a maximal surface coverage of 504 ng/cm². © 2019 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc.