Preparation and characterization of chitosan based metal nanoparticles and study of their antibacterial property

Abstract

Chitosan is a natural polysaccharide and has significant biological and chemical properties such as biodegradability, biocompatibility, bioactivity, microbial activity and polycationicity. In this research, chitosan based nanoparticles have been prepared for bacteriological application. Chitosan has been prepared and characterized from locally available waste shrimp shell. Prepared chitosan have been used as the raw material for the production of chitosan based metal nanoparticles such as Chitosan based zinc nanoparticle (Chi-Zn NPs), Chitosan based copper nanoparticle (Chi-Cu NPs) and Chitosan based cadmium nanoparticle (Chi-Cd NPs). First chitin has been has been isolated from shrimp shell by demineralization and deproteinization followed by deacetylation to get chitosan. Purity and characteristics of chitosan isolated from shrimp shell has been compared with those of extra pure chitosan purchased from Sisco Research Laboratories (SRL) Private Limited, India. It was characterized by Fourier Transform Infra Red (FTIR) Spectroscopy, solubility, moisture and ash content. It has been found that moisture and ash content of prepared chitosan is 1.25%, 1.22% respectively while those for purchased extra pure chitosan is 1.24% and 1.19%. Both are readily soluble in 1% acetic acid and produce transparent viscous solution. FTIR result of the extracted chitosan is very much comparable to the standard one. It has been seen that there is an excellent agreement between extracted and purchased chitosan. Chitosan based metal nanoparticles have been synthesizes by solution casting method. But the techniques and conditions are different from previous studies [83, 84]. The synthesized NPs were characterized by using FTIR, TGA and SEM analysis. FTIR spectra of the NPs (except Chi-Cd) are very similar to those of the synthesized chitosan. This indicates the presence of chitosan polymer in the NPs matrices. The loss of mass in TG analysis also confirms the presence of chitosan polymer in the Chi-Zn NPs. SEM photograph clearly showed the synthesized materials are nanomaterials within the range of 1-100 nm. Produced NPs exhibited enhanced antibacterial activities. Zone of inhibition against Pseudomonas aeruginosa, Salmonella bovismorbificans, Salmonella typhi and Escherichia coli bacteria of Chi-Zn, Chi-Cu, Chi-Cu(II) and Chi-Cd NPs are 38, 31, 30 and 39 mm; 32, 36, 37 and 32 mm; 30, 35, 36 and 33 mm and 35, 31, 31 and 38 mm respectively, while those for standard drug kanamycin are 22, 22, 20 and 20 mm respectively.