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Organisationseinheit der BAM
Polyglycerol (PG) coated polypropylene (PP) films were synthesized in a two-step approach that involved plasma bromination and subsequently grafting hyperbranched polyglycerols with very few amino functionalities. The influence of different molecular weights and density of reactive linkers were investigated for the grafted PGs. Longer bromination times and higher amounts of linkers on the surface afforded long-term stability. The protein adsorption and bacteria attachment of the PP-PG films were studied. Their extremely low amine content proved to be beneficial for preventing bacteria attachment.
Active antibacterial and antifouling surface coating via a facile one-step enzymatic cross-linking
(2017)
Prevention of microbial contamination of surfaces is one of the biggest challenges for biomedical applications. Establishing a stable, easily produced, highly antibacterial surface coating offers an efficient solution but remains a technical difficulty. Here, we report on a new approach to create an in situ hydrogel film-coating on glass surfaces made by enzymatic cross-linking under physiological conditions. The cross-linking is catalyzed by horseradish peroxidase (HRP)/glucose oxidase (GOD)-coupled cascade reactions in the presence of glucose and results in 3D dendritic polyglycerol (dPG) scaffolds bound to the surface of glass.
These scaffolds continuously release H2O2 as long as glucose is present in the system. The resultant polymeric coating is highly stable, bacterial-repellent, and functions under physiological conditions. Challenged with high loads of bacteria (OD540 = 1.0), this novel hydrogel and glucose-amended coating reduced the cell viability of Pseudomonas putida (Gram-negative) by 100% and Staphylococcus aureus (Gram-positive) by ≥40%, respectively. Moreover, glucose-stimulated production of H2O2 by the coating system was sufficient to kill both test bacteria (at low titers) with >99.99% Efficiency within 24 h. In the presence of glucose, this platform produces a coating with high effectiveness against bacterial adhesion and survival that can be envisioned for the applications in the glucose-associated medical/oral devices.
Graphene and its derivatives have recently attracted much attention for sensing and deactivating pathogens. However, the mechanism of multivalent interactions at the graphene–pathogen interface is not fully understood. Since different physicochemical parameters of graphene play a role at this interface, control over graphene’s structure is necessary to study the mechanism of these interactions. In this work, different graphene derivatives and also zwitterionic graphene nanomaterials (ZGNMs) were synthesized with defined exposure, in terms of polymer coverage and functionality, and isoelectric points. Then, the switchable interactions of these nanomaterials with E. coli and Bacillus cereus were investigated to study the validity of the generally proposed “trapping” and “nano-knives” mechanisms for inactivating bacteria by graphene derivatives. It was found that the antibacterial activity of graphene derivatives strongly depends on the accessible area, i.e. edges and basal plane of sheets and tightness of their agglomerations. Our data clearly confirm the authenticity of “trapping” and “nano-knives” mechanisms for the antibacterial activity of graphene sheets.