pH-Responsive Smart Wettability Surface with Dual Bactericidal and Releasing Properties

Biomaterial-associated infections caused by pathogenic bacteria have important implications on human health. This study presents the design and preparation of a smart surface with pH-responsive wettability. The smart surface exhibited synergistic antibacterial function, with high liquid repellency against bacterial adhesion and highly effective bactericidal activity. The wettability of the surface can switch reversibly between superhydrophobicity and hydrophobicity in response to pH; this controls bacterial adhesion and release. Besides, the deposited silver nanoparticles of the surface were also responsible for bacterial inhibition. Benefiting from the excellent liquid repellency, the surface could highly resist bacterial adhesion after immersing in a bacterial suspension for 10 s (85%) and 1 h (71%). Adhered bacteria can be easily eliminated using deposited silver nanoparticles during the subsequent treatment of alkaline bacterial suspension, and the ratio of deactivated bacteria was above 75%. After the pH returned to neutral, the deactivated bacteria can be easily released from the surface. This antibacterial surface showed an improved bacterial removal efficiency of about 99%. The results shed light on future antibacterial applications of the smart surface combining both bactericidal and adhesion-resistant functionalities.