Study of the nanomaterials and their antimicrobial activities.

摘要

In the last decade, the world faced huge problems associated with the spread of antimicrobial resistant infections that are essentially untreatable such as methicillin resistant Staphylococcus aureus (MRSA) infection. These infections have begun to occur in both hospital and community environments. Developing new antimicrobial surface coatings can hold a great promise to minimize and control various problems that associated with the spreading of infections and biofilms formation, these coatings can be used in medicine where medical devices associated with severe infections, in construction industry and the in food packaging industry. It has been established that single-walled CNTs exhibit a strong antimicrobial activity and can pierce bacterial cell walls.;Recently, nanomaterial structures that made from pure carbon such as CNTs have been seen as promising candidates for many potential applications in Biotechnology and bioscience due to the combination of their extraordinary properties that arise from surface area, light weight, strength, flexibility, unique electrical conductivity and many more novel physical and chemical properties at nanoscale level. CNTs have been used widely in biomedical field including drug delivery, gene therapy and creating new biomedical devices with novel properties. Researchers have now made a first step to add carbon nanotubes to antimicrobial agents list. There are two types of CNTs have been used in biomedical research. The first one is a single-walled carbon nanotube (SWNT) and the second is a multi-walled carbon nanotube (MWNT).;Recent in vitro studies suggest that carbon nanotubes have antimicrobial activity and coating CNTs with nickel nanoparticle could enhance the antimicrobial activity of cabon nanotubes. In order to test this hypothesis, nickel nanoparticles were deposited on carbon nanotubes (CNTs) by electrochemical deposition.;The carbon nanotubes used in this study were XD-CNTs, SWNTs and Ni-coated CNTs. The structure and the morphology of Ni-coated CNTs were investigated by scanning electron microscopy (SEM), dispersive x-ray analysis (EDX) and thermo gravimetric analysis (TGA). The SEM results revealed that CNTs provide an excellent surface for electrochemical deposition of nanomaterials. Ni nanoparticles were homogeneously electrodeposited on the surfaces of SWNTs. Antimicrobial activity of CNTs was determined by broth dilution method using six different bacterial strains, three strains of gram negative and three strains of gram positive bacteria. The gram positive bacteria include Staphylococcus aureus, Staphylococcus epidermidis and Bacillus subtilis . The gram negative bacteria include Eshericia coli, Klebsiella pneumonia and Pseudomonas aerugenosa. Bactericidal rate was calculated. Based on the results Ni-coated CNTs show much stronger bactericidal property comparing to SWNTs and XD-grade CNTs.