Eco-Friendly Activation of Silicone Surfaces and Antimicrobial Coating with Chitosan Biopolymer

Silicone is widely used in medical devices due to its mechanical properties and biocompatibility; however, microbial contamination of silicone surfaces, which can lead to nosocomial infections, remains a significant concern. This can be countered by surface modification using techniques commonly involving oxidative plasma activation or ozone treatments, followed by treatment with silanization agents. Here, we report an alternative surface modification procedure involving treatment with non-toxic organic hydroxyl amines or diamine dissolved in eco-friendly solvents, thus avoiding using reactive and potentially harmful compounds and not requiring specialized equipment. Our findings demonstrate that ethanolamine in isopropanol effectively activates silicone without compromising its tensile strength, making it ideal for further modification. The activated surfaces showed stable amino group areal concentrations over a 10-day period, confirmed by fluorescence imaging and ninhydrin assays. Subsequent treatments with glutaraldehyde and chitosan enhanced the antibacterial properties of the silicone. Chitosan-coated silicone significantly reduced Gram-positive and Gram-negative bacteria colony-forming units (CFUs), with Enterococcus faecalis CFUs decreasing from 7.1 to 3.7 Log₁₀ CFU/mL. This study introduces a sustainable activation technique for silicone surfaces, resulting in medical devices with improved resistance to microbial colonization while maintaining their mechanical integrity.