Facile preparation of zwitterionic core-shell nanogels for dual-functional coatings: Combining antifouling and antibacterial features in silicon implant model surface modification

To develop surface-coating technology for fabricating functionalized biomedical implant and overcome implant-associated bacterial infections, this study presented an innovative antifouling and antibacterial dual-functional nanogel coating methodology for engineering silicon-based biomedical implants/biochips. Firstly, zwitterionic core-shell PAA@(GMA/SBMA) nanogels were designed and prepared via reflux-precipitation polymerization and were characterized through NMR, FTIR, DLS, AFM and TEM. The nanogels exhibited uniform and spherical morphology, salt-ion responsiveness, and high lysozyme loading capability. Subsequently, the PAA@(GMA/SBMA) nanogels were covalently grafted onto the surface of silicon wafers, via an epoxy-amine ring-opening reaction, to prepare nanogel-coated silicon wafers (Si@nanogels). A comprehensive array of characterization techniques, including SEM-EDS, contact angle measurements, and XPS, validated the effective nanogel-coating. These coatings demonstrated notable resistance to protein adsorption, highlighting their robust antifouling properties. Upon loading with the antibacterial agent lysozyme, the nanogel coating displayed remarkable antibacterial efficacy against both Gram-negative (E. coli) and Grampositive (S. aureus) bacteria and effectively inhibited biofilm formation. Furthermore, the nanogel coatings exhibited good biocompatibility and dynamic stability, thus facilitating the surface-mediated adhesion and growth of fibroblast 3T3 cells. Significantly, this work provided a facile, economic and efficient surface modification approach to fabricate nanogel-coated antifouling/antibacterial dual-functional biomedical implant model towards potential clinical applications.