Preparation and antibacterial character of a water-insoluble antibacterial material of grafting polyvinylpyridinium on silica gel

Abstract

Micron-sized silica gel particles were modified with the coupling agent of 3-methacryloylpropyl trimethoxysilane (MPS), then the copolymer of 4-vinyl pyridine and acrylamide (P (4VP-co-AM), PVA) was grafted onto the surface of modified silica gel particles by adopting the “grafting from” way, and the grafted particles PVA/SiO 2 were obtained. Finally, PVA on the particles PVA/SiO 2 were quaternarized by using benzyl chloride or dimethyl sulfate as quaternization reagents, and a kind of water-insoluble antibacterial material QPVA/SiO 2 with pyridinium-type was prepared. In this paper, the antibacterial property of QPVA/SiO 2 was mainly investigated by using Escherichia coli ( E. coli) as model bacterium and by the colony count method, the effects of the grafting degree of pyridinium and the variety of quaternization reagents on the antibacterial property of QPVA/SiO 2were examined, and the antibacterial mechanism of QPVA/SiO 2 was explored using the method of measuring the activities of β- d-galactosidase and TTC-dehydrogenase. The experiment results show that QPVA/SiO 2 possesses strong antibacterial ability, and the antibacterial ratio of QPVA/SiO 2 with 2.3 mmol/g of grafting degree of pyridinium can reach 100% for bacterium suspension of 10 9 CFU/mL with the dosage of 20 g/L and for 10 min of contact time. The greater the grafting degree of pyridinium is, the stronger the antibacterial ability, and the antibacterial property of the QPVA/SiO 2 prepared using benzyl chloride as quaternization reagent is stronger than that of the QPVA/SiO 2 prepared using dimethyl sulfate. The experimental results of two kinds of enzyme activity measurements reveal that the antibacterial effect of QPVA/SiO 2 is based on a sterilization process and not only based on a restraining action.