title: Preparation and antibacterial characteristic of water-insoluble antibacterial material QPEI/SiO2.
abstract: Polyethyleneimine (PEI) was grafted onto micron-sized silica gel particles via the coupling action of gamma-chloropropyl trimethoxy silane, and grafting particles PEI/SiO(2) was prepared. Then, polymeric reactions of two steps, tertiary amination reaction and quaterisation, were conducted for the grafted PEI. After quaterisation of the grafted polyethyleneimine, a composite particle, QPEI/SiO(2), was obtained. QPEI/SiO(2) is a water-insoluble antibacterial material. In this work, the antibacterial characteristic of QPEI/SiO(2) was mainly investigated using Escherichia coli (E. coli) as a disease-leading bacterium and adopting a colony count method. The effects of quaterisation degree of PEI and pH of the medium on the antibacterial ability of QPEI/SiO(2) were examined. The antibacterial mechanism of QPEI/SiO(2) was explored profoundly by using two enzyme activity determination methods, beta-D-galactosidase activity determination and TTC-dehydrogenase activity determination. The experimental results indicates that the water-insoluble antibacterial material QPEI/SiO(2) possesses strong antibacterial ability, for the bacterial suspension with a concentration of 10(9) CFU/ml, the antibacterial ratio of QPEI/SiO(2) can reach about 100% only with a dosage of 15 g/l and only for a contact time of 10 min. The main factors influencing the antibacterial ratio of QPEI/SiO(2) are the quaterisation degree of the grafted PEI and pH value of the medium. QPEI/SiO(2) with higher quaterisation degree has stronger antibacterial ability. In a certain range of pH value, the higher the pH value of the medium is, the stronger the antibacterial ability of QPEI/SiO(2 )is. Enzyme activity determination results show that the antibacterial mechanism of the water-insoluble antibacterial material QPEI/SiO(2) is based on a sterilization process and not only is a bacteriostasis action.
authors.affiliation: Department of Chemical Engineering, North University of China, Taiyuan 030051, PR China. gaobaojiao@126.com
authors.forename: Baojiao
authors.initials: B
authors.lastname: Gao
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D004926:Escherichia coli / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D011073:Polyamines / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry; D058428:Silica Gel; D012822:Silicon Dioxide / Q000737:chemistry*; D012995:Solubility; D013234:Stem Cells; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D011073:Polyamines; D014867:Water; D058428:Silica Gel; D012822:Silicon Dioxide; D011094:Polyethyleneimine; D001616:beta-Galactosidase