Isolation of chitosan from fish scales of Catla catla and synthesis, characterization and screening for larvicidal potential of chitosan-based silver nanoparticles.

Background and Objectives: Chitosan is the major component present in fish scales and crustacean shell waste. Chitosan was isolated from scales of fish waste of Catla (Catla catla) by chemical method involving demineralization, deproteinization, and deacetylation. Methods: Chitosan isolated from fish scales was confirmed qualitatively by Richard's method. Further, it was quantitatively analyzed and was found to contain 6 g of chitosan (100 g of dried fish scales). Chitosan had been characterized using Fourier transform infrared spectrometry analysis. A new method of preparing silver nanoparticles combined with chitosan is used here. It was characterized using ultraviolet and scanning electron microscopy analysis. The potential of chitosanbased silver nanoparticles against Culex (III instar) and Anopheles (IV instar) was screened, and biochemical parameters of the larval tissues were also estimated. Results: Protein, carbohydrate, lipid, acid phosphatase, alkaline phosphatase, and lactate dehydrogenase content were found to be decreased in the treated larval tissues when compared to the control in both mosquito species. Conclusions: Decreased levels of biochemical contents are indicating the high toxic capacity of chitosan silver nanoparticles. [ABSTRACT FROM AUTHOR]