Biofouling on medical devices generally causes adverse complications, such as thrombosis, infection, and pathogenic calcification. Silicone is a widely used material for medical applications. Its surface modification typically encounters undesirable "hydrophobic recovery", leading to deterioration of surface engineering. In this study, we developed a stable superhydrophilic zwitterionic interface on polydimethylsiloxane (PDMS) elastomer by covalent silanization of sulfobetaine silane (SBSi) to resist nonspecific adsorption of bacteria, proteins, and lipids. SBSi is a zwitterionic organosilane assembly, enabling resisting surface reconstruction by forming a cross-linked network and polar segregation. Surface elemental composition was confirmed by X-ray photoelectron spectroscopy (XPS), and the long-term stability of modification was accessed using a contact angle goniometer. The biofouling tests were carried out by exposing substrates to bacterial, protein, and lipid solutions, revealing the excellent bioinertness of SBSi-tailored PDMS, even after 30 day storage in ambient. For the real-world application, we modified commercially available silicone hydrogel contact lenses with developed zwitterionic silane, presenting its antibacterial adhesion property. Moreover, the cytotoxicity of SBSi was accessed with NIH-3T3 fibroblast by the MTT assay, showing negligible cytotoxicity up to a concentration of 5 mM. Consequently, the strategy of surface engineering in this work can effectively retard the "hydrophobic recovery" occurrence and can be applied to other silicone-based medical devices in a facile way.

A facile yet effective surface modification strategy for superhydrophilicity and underwater superoleophobicity was developed by silanization of zwitterionic sulfobetaine silane (SBSi) on oxidized surfaces. The coatings exhibit excellent wetting properties, as indicated by static contact angles of <5°, and long-term stability under exposure to heat and UV irradiation. The SBSi-modified surfaces were employed for applications in antifog, self-cleaning, and oil-water separation. The SBSi glasses retained their optical transmittance because of the rapid formation of coalesced water thin films on surfaces in contact with water vapor and moisture. In addition, the underwater-oil contact-angle measurements verified the underwater superoleophobicity of the zwitterionic SBSi coatings. The oil spills on the SBSi coating could be readily removed in contact with water to realize the self-cleaning property. Besides, we modified stainless steel wire meshes with SBSi for oil-water separation. The optimal oil recovery rate for the oil-water mixtures reached >99.5% when using the SBSi-coated meshes with a pore size of 17 μm. More importantly, the water flux with modified meshes achieved 6.5 × 10(7) L/m(2)·h·bar, enabling gravity-driven and energy-saving separation. Consequently, we demonstrated the superhydrophilicity and underwater superoleophobicity of SBSi, offering promise in solving technological problems of interfacial fog, oil spills, and oil-water separation and thereby showing great potential in large-scale commercial applications.

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