Hydrazone-linked soybean protein isolate-carboxymethyl cellulose conjugates for pH-responsive controlled release of pesticides

To improve the utilization of pesticides and reduce the amount of pesticides used, sustained-release nanoparticles were prepared. Soybean protein isolate (SPI) and carboxymethyl cellulose (CMC) were modified to obtain hydrazine-modified SPI and aldehyde-modified CMC, respectively, and SPI-CMC was prepared by the condensation of hydrazine and aldehyde groups, forming a hydrazone bond. SPI-CMC was heated and loaded with avermectin (AVM) to obtain AVM/SPI-CMC. The encapsulation efficiency property, anti-ultraviolet property, sustained-release characteristics, pH responsiveness, and toxicological profiles were studied. The particles in the formulation were spherical-like, with sizes ranging between 150 and 250 nm. The encapsulation efficiency increased with the addition of SPI, which reached 44.49% when SPI was added in a mass ratio of m SPI-HYD : m CMC-ALD  = 2:1. The percentage of remaining AVM in AVM/SPI-CMC was 31.47% higher than that in the AVM solution after UV irradiation for 43 h. Moreover, the nanoparticles were responsive to pH. SPI-CMC had no significant effect on the insecticidal toxicity of AVM. Environmental friendly SPI-CMC could protect and release pesticides continuously, which could improve the efficiency of pesticides.