Synthesis Of Doped C12A7–O~- Nano-material By Sol-gel Method And Features Of Application

It is well known that diseases, caused by microorganism such as bacteria and viruses, frequently broke out since time immemorial. In order to prevent human beings from infection of pathogenic bacteria, several of antibacterial materials have been explored. Recently, the antibacterial activity of metallic oxides attracts researchers as the promising inorganic antibacterial materials that can substitute for conventional organic agents. The application of these materials has the advantages including strong antibacterial activity without the light irradiation and some mineral elements being beneficial to the human body.Present study provides an approach to produce the nano-crystal material of Na₂O doped 12CaO?7Al2O3 (C12A7) by the sol–gel method, which was successfully applied for the antibacterial material. The resulting particles showed an excellent antibacterial performance. The morphology change of the bacteria was observed by field emission-scanning electron microscope (FE-SEM). The antibacterial mechanism of the C12A7-Na₂O material was also discussed. Main work was listed:1. The doped nanocrystal 12CaO·7Al2O3 (C12A7-O^-) was successfully synthesized by the sol-gel combustion method, which is more convenient than conventional method for the synthesis of material. The conventional method needs very high temperature and long time. The sol-gel combustion method reduced not only the temperature needed but also the time. Though kinds of chemical analysis method, we found that the doping process did not change the cystal structure of the material and the ions emission from the surface of the material din not destroy too. From TOF-MS spectra, we found that the kind of ions emitted from doped C12A7 is same as that from the surface of C12A7, as well as the concentration of the ions.2. The antibacterial activity of nanocrystal C12A7-O^- was enhanced by doping sodium oxide. The results of antibacterial experiment showed that the antibacterial activity is higher by doping sodium oxide, and the doped C12A7-O^- nanoparticles exhibited excellent antibacterial activity agaist both E.coil and S. aureus. The present material could be potentially used as an excellent antibacterial material due to its unique features such as thermal stable, environment-friendly and safe.3. The antibacterial mechanism of the doped nanocystal C12A7-O^- particle was firstly investigated. From the experimental results, we found that the most important factors effected the antibacterial activity of the material include follow elements: (1) the electrostatic interactions between the bacteria surface and the lattic framework of the material with positive charge; (2) the active oxygen species, such as O^- anion; (3) the pH value in local positon of the material was increased by doping sodium oxide, then it effected the total antibacterial activity of the material.