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

Abstract

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 mSPI-HYD:mCMC-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. Soybean protein isolate (SPI) was bonded to carboxymethyl cellulose (CMC) by a hydrazine bond to prepare SPI-CMC carriers for pesticide applications. AVM/SPI-CMC was obtained by encapsulating avermectin (AVM) with SPI-CMC through thermal denaturation. SPI-CMC could improve the anti-UV performance of AVM and slow down the decomposition rate of AVM. The hydrazone bond and carboxyl groups showed pH responsiveness, which could release drugs rapidly in an acidic environment. Environmentally friendly SPI-CMC could protect and release pesticides continuously, which could improve the efficiency of pesticides.