Preparation and Antibacterial Activity of Chitosan/Organic Laponite Nanocomposites

Laponite-based secondary intercalation compound was prepared by ion exchange method through inter- calating quaternary ammonium salts and chitosan into the layers of hectorite. The layer spacing of the two kinds of secondary intercalation compounds were increased 0.276 nm and 0.262 nm, respectively, compared to the pure la- ponite. The antibacterial of secondary intercalation compound was tested by Escherichia coli (E. coli) and Staphy- lococcus aureus (S. cereus). Antibacterial ability of the two kinds of secondary intercalation compounds were de- termined by using bacteriostatic ring and plate count methods. The results showed that, after being contacted with the two compounds for 24 h, the bacteriostatic rate of the laponite/myristyl trimethyl ammonium bromide/chitosan on E. coli reached up to 100% and 85% on S.cereus. Meanwhile, the laponite/cetyl trimethyl ammonium bro- mide/chitosan was up to 99% on E. coli and S. cereus. The antibacterial process and mechanism on E. coli and S. cereus of the two kinds of compounds were investigated by scanning electron microscope and β-galactosidase ac- tivity. The results showed that the compound adsorbed bacterial through the role of mutual attraction between posi- tive and negative charges at first, then the compound penetrated the bacterial cell membrane with the help of hy-