Synthesis and Antibacterial Performance of Functional Organic–Inorganic Silica Nanocomposites Based on Novel Zwitterionic Polymer

Abstract

Nano-sized silica particles (SiO2 NPs) of 30 ± 5 nm were modified by the coupling agent of triethoxyvinylsilane and polymer 4-vinyl pyridine (P4VP) was “grafted” onto the surface of modified SiO2 NPs by adopting the “grafting from” way. Then, the P4VP brush of SiO2 NPs was quaternized by ethyl bromoacetate, iodoethane, 3-bromopropionic acid and 1,3-propanesulfonate to obtain four water-insoluble, functional and novel organic–inorganic silica nanocomposites (SiO2/P4VP-eb, SiO2/P4VP-ie, SiO2/P4VP-bpa and SiO2/P4VP-psl), respectively. The antibacterial performance of four functional silica nanocomposites above was investigated by using Escherichia coli ATTC25922 as model bacterium via the colony count method. When the sterilizing ratios of SiO2/P4VP-psl, SiO2/P4VP-bpa, SiO2/P4VP-eb and SiO2/P4VP-ie against E. coli with bacterium age of 4 h (OD600 nm = 2.5) reached 100%, the critical concentration value was 3, 5, 12 and 11 mg/mL, respectively. The results showed that although four functional silica nanocomposites all possessed excellent antibacterial ability, zwitterionic silica nanocomposites (SiO2/P4VP-psl, SiO2/P4VP-bpa) possessed stronger antibacterial ability than cationic silica nanocomposites (SiO2/P4VP-eb, SiO2/P4VP-ie).