Squid pen chitosan nanoparticles: small size and high antibacterial activity

Abstract

Chitosan nanoparticles (CSNs) have widely studied for many potential applications as a bioactive nanomaterial because of their excellent properties, such as quantum size effect, large surface area, high mobility, and high permeability. In this study, various CSNs prepared from squid pen chitosan with different molecular weight (Mw) and degree of deacetylation (DD). The lower Mw and higher DD of initial chitosan used, the smaller size of CSNs obtained. Small size CSNs (about 30 nm) are formed from the initial chitosan (Mw of 8 kDa, DD of 96%). In vitro tests, all as-prepared CSNs showed high antibacterial activity against Salmonella sp. and Staphylococcus aureus. In particular, the lowest CSNs concentration of 50 ppm, which was prepared from chitosan with a low Mw of 8 kDa and high DD of 96%, showed the highest activity. Besides, by using the similar initial chitosans, CSNs prepared from squid pens exhibit higher antibacterial activity than that one from shrimp shells. This study presents high potential applications of CSNs prepared from squid pen chitosan with small size and excellent antibacterial activity for various fields.