Research On Preparation And Performance Of Quaternarized N-halamine Polymer-Functionalized Nanodiamonds

In recent year,microbial threats to human health and safety have become a serious public problem.Antibacterial materials can effectively inhibit the growth of microorganism and have attracted significant research interests.Antibacterial materials have been widely used in the area of medical devices,water treatment,food packaging,food storage,hygienic products,etc.Nanodiamonds have promising applications in many areas due to their excellent optical mechanical,and thermal properties,especially in antibacterial field.N-halamine antibacterial materials have attracted growing attention because of their unique properties,such as powerful antibacterial efficacy,good stability and regenerability,safety to humans and environment,which can inactivate microorganisms in only seconds time by a direct transfer of oxidative chlorine from the N-halamines to bacterial cells.On the other hand,the polymeric quaternary ammonium compounds can provide rich positive charges to kill bacteria by adsorption to the surface of bacteria,as well as improve the dispersion properties of functionalized nanoparticles.In this work,two quaternarized N-halamine polymer-functionalized nanodiamonds were synthesized,and their chemical modification,dispersity and antibacterial performances against Gram-positive and Gram-negative bacteria were investigated.1.Polycation-based N-halamine functionalized nanodiamonds(PCN-NDs)were fabricated by coating of nanodiamonds(NDs)with quaternarized N-halamine polymers via a facile approach.The morphology and chemical composition of modified nanoparticles were characterized by thermogravimetric analysis(TGA),Fourier transform infrared spectra(FT-IR),X-ray photoelectron spectra(XPS),and transmission electron microscope(TEM).It was found that tight core aggregates of NDs could be broken into 40-50nm nanoparticles through functionalization,which resulted in stable colloidal dispersion solution over one month.The antibacterial experiment showed that PCN-NDs eliminated nearly 100%of E.coil and S.aureus(107-108 CFU/mg nanoparticles)within 15 min.Furthermore,the as-prepared antimicrobial PCN-NDs exhibited good storage stability and regenerability2.Cyclic N-halamine modified chitosan/nanodiamonds were fabricated by coating of nanodiamonds(NDs)with cyclic N-halamine modified chitosan.The morphology and chemical composition of modified nanoparticles were characterized by thermogravimetric analysis(TGA),Fourier transform infrared spectra(FT-IR),X-ray photoelectron spectra(XPS),and transmission electron microscope(TEM).It was found that the modification process settled the problems of poor dispersion stability of NDs but also rendered the nano-material antibacterial property.The antibacterial experiments showed that Cl-DMH-CTS-NDs eliminated nearly 100%of E.coil and S.aureus(107-108 CFU/mg nanoparticles)within 30 min.Furthermore,once all of the oxidative chlorine was consumed,the recovery of antibacterial activity can be simply done by exposuring coated materials to dilute household bleach.