Chitosan And Its Derivatives Nanoparticles:Preparation And Application In Antibacterial Paper

Paper and its products are closely related to our lives and work. Since paper contaminated by bacteria gives rise to the spread of disease, increasing attention has been focused on the research of antibacterial paper. At present antibacterial material used in paper includes three categories, organic, inorganic and natural material. Inorganic and natural antibacterial materials have several advantages over traditionally used organic synthesized agents, such as chemical stability, thermal resistance, safety to the user, long lasting action period, etc. However, the inorganic antibacterial agents are costly, so rich natural antibacterial agents demonstrate certain superiority. One of the most commonly used natural antibacterial agents is chitosan. Chitosan, which has a wide-spectrum of antibacterial activity, is a nontoxic biopolymer derived by partially deacetylation of chitin.Chitosan nanoparticles (CSNP) were obtained by H2O2degradation of chitosan. Their morphology and size were determined by atomic force microscope (AFM), the particles were smooth and approximately36nm in size.To prepare N, O-Carboxymethyl chitosan (N, O-CMCS) with good water-solubility, chitosan was modified with monochloroacetic acid in the presence of sodium hydroxide. The structure of N, O-CMCS was characterized by FT IR, and it was proved that substitution reaction both occurred on the N element and O element. The DS and its antimicrobial activity were studied. N, O-CMCS nanoparticles were prepared using dispersion-crosslinking method with TPP as crosslinker.2-Hydroxypropyl trimethyl ammonium chloride chitosan (HTCC) were prepared from chitosan and3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA). The structure of HTCC was characterized by FT IR.Antibacterial activity of CSNP, N, O-CMCS, HTCC and N, O-CMCS nanoparticles against E. coli (Gram-negative bacteria) and S. aureus (Gram-positive bacteria) was measured by the inhibition zone and (or) bacterial reduction methods.Results showed that antibacterial activity of CSNP, N, O-CMCS, HTCC and N, O-CMCS nanoparticles was improved with their concentration increase. At a concentration of5mg/mL, the antibacterial rate of CSNP against E. coli and S. aureus reached approximately95%and81%. At the same concentration, the antibacterial rate of N, O-CMCS reached approximately55%and82%. The antibacterial rate of N, O-CMCS nanoparticles reached approximately99%and98%, respectively.Several antibacterial agents were used in antibacterial paper by addition in pulp, impregnation, and insufflation. In addition, the antibacterial activity of antibacterial paper was determined by inhibition zone method. All of the antibacterial paper showed certain antibacterial activity, and appeared clear inhibition zone around the samples. For E. coli, at a CSNP concentration of10mg/mL, the inhibition zone reached8.0mm. For S. aureus, the inhibition zone was6.8mm.