Silane-functionalized TiO2 nanoparticles decorated with Ag nanoparticles for dual antimicrobial effects

TiO2 and Ag nanoparticles (NPs) have attracted considerable attention in recent years due to the interesting antibacterial application of a single nanoplatform of these two components [1,2]. The direct TiO2-Ag conjugation is still challenging and opens applicative perspectives as a multifunctional nanotool for dual antimicrobial activity. In the present work, (3-mercaptopropyl)trimethoxysilane (3MPTMS) was selected as a bifunctional linker bearing –SH and –O moieties to mediate the chemical attachment of soft AgNPs to hard TiO2NPs. Moreover, the 3MPTMS linker can improve the stability and biocompatibility of TiO2-Ag nanoconjugate. Regarding the synthesis, commercially available TiO2NPs with a mean size of 50 nm were firstly functionalized with 3MPTS (hydrolyzed form of 3MPTMS) through the formation of Ti–O–Si bonds and then Ag ions were coordinated to the –SH groups of the TiO2NPs-3MPTS followed by reduction to the AgNPs forming the final TiO2-3MPTS-Ag nanohybrid. Different reducing agents were tested for both reduction of the coordinated-Ag+ and stabilization of the resultant AgNPs on the surface of TiO2NPs-3MPTS. The stability, size, morphology, and chemical composition of the nanoparticles were evaluated by extensive characterizations including FTIR-ATR, FESEM-EDS, and DLS. Thanks to multidisciplinary collaborations, the in vitro antibacterial property of this TiO2-Ag nanohybrid is in progress.