Synthesis of chitosan nanoparticles by TPP and their potential mosquito larvicidal application

Nowadays chitosan nanoparticles (CS NPs) have been extensively considered for biomedical applications. The purpose of this paper is to summarize the results of larvicidal activities of extracted chitosan and synthesized CS NPs from shrimp shells against third-instar larvae of mosquitoe Aedes aegypti (A. aegypti). The CS NPs exhibited higher larvicidal activity in comparison to extracted and commercial chitosan. In the present study, the chitosan was extracted from shrimp shells (Penaues indicus) and the CS NPs were synthesized by a novel method of ionic gelation with sodium tripolyphosphate (TPP) as a reducing agent. The chitosan was morphologically characterized by fourier transforms infrared (FTIR) spectra, X-ray diffraction (XRD) and scanning electron microscope (SEM), whereas the CS NPs were characterized using FTIR, XRD, atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). The synthesized CS NPs were spherical in shape. The HRTEM images presented that the CS NPs were composed of a segment of small particles (8 nm) and of a second segment of larger particles (80 nm), attributing to the rearrangement of particles after the addition of TPP. The larvicidal activity of CS NPs was confirmed against third instars larvae of A. aegypti. The LC₅₀ value observed was 66.42 mg/L and the corresponding LC₉₀ value was 92.58 mg/L. From this study, it is established that these shell waste materials could be potentially employed for biomedical applications.