Functional Nanogel Coatings as Antifouling and Antibacterial Surfaces

Biomedical implants and devices have made a great impact on the quality of patient's lives by improving and extending the functionality of essentials elements in the body systems. Hip and breast implants, voice prosthesis, artificial heart valves and stents, urinary catheters, vascular grafts, and dental implants are just some examples, and the use of these biomedical implants and devices is rapidly growing. However, the risk of an infection that could end up in a complete malfunctioning always comes along with the biomaterials; alternative and effective approaches are urgently needed to prevent and control biofilm infections. In this context, using particles, namely "nanogels" as surface coatings, offer a promising solution thanks to their great hydrogel-like structure and bacteria repelling capability to inhibit the initial bacteria adhesion on the surface to avoid biofilm formation. This work involves understanding the synthesis and modification mechanism of different nanogels; further, the production, optimization and characterization of model surface coatings; and finally, the conceiving the antimicrobial properties of these nanogel coatings. As shown in the thesis in Chapter IV, nanogel coatings successfully yielded more than 98% reduction in the initial bacterial adhesion, thus can be considered as antifouling coatings for future applications. Moreover, the further chemical modification of the nanogels provided excellent bacteria-killing properties; therefore, when applied as a coating, it showed a killing efficacy of up to 99.99% of adhering bacteria on the surface compared to non-modified nanogel coatings while still possessing an antifouling activity as can be seen in Chapter V.