Preparation And Properties Of Modified Zein Loaded Avermectin Nano-pesticide

Compared with traditional pesticide formulation,nano-pesticide formulation has many advantages such as high efficiency,environmental protection,high targeted delivery and intelligent controlled release.This is the research hotspot of pesticide formulation at present.Zein is a hydrophobic protein,and it has the advantages of biocompatibility,biodegradability,anti-oxidation and non-toxicity,and can be used as a carrier of nano-pesticides.However,it is difficult to dissolve in water due to its unique solubility.Zein needs to be hydrophilic modified to realize the nano-level pesticides.In order to improve the utilization ratio of pesticides,nano-pesticides were further modified to improve their properties.In this study,P-Zein and Zein-EGDE pesticide carriers were prepared by hydrophilic modification of Zein with sodium triphosphate and ethylene glycol diglycidyl ether(EGDE),respectively.Then,the P-Zein was physically modified with CMC-g-PDMDAAC and loaded with Avermectin(AVM)to obtain AVM@P-Zein/CMC-g-PDMDAAC nano-pesticides.Moreover,Zein-CMC was synthesized by chemical modification of Zein-EGDE with CMC-g-P(HEMA-MMA)and loaded with AVM to obtain AVM@Zein-CMC nano-pesticides.The stability,encapsulation efficiency,anti-ultraviolet(UV),adhesion,sustained-release characteristics and toxicological properties of nano-pesticides were studied.The results are as follows:(1)In order to improve the hydrophilicity of Zein,realize the nano-pesticide,and improve the utilization ratio of pesticide,the nano-pesticide of Avm@P-Zein is prepared by modifying Zein with sodium triphosphate and loading AVM.Then,CMC-g-PDMDAAC was used to encapsulate AVM@P-Zein to obtain AVM@P-Zein/CMC-g-PDMDAAC nano-pesticide.The results show that Avm@P-Zein can disperse in water stably and its average particle size is 215 nm the average particle size of AVM@P-Zein/CMC-g-PDMDAAC is 360 nm.Compared with AVM@P-Zein,AVM@P-Zein/CMC-g-PDMDAAC has better dispersion property,the encapsulation efficiency increases from 81.52% to 82.11%,the anti-UV property is improved by 10%,the adhesive property is improved by 20%,and the drug release is slowed down.AVM@P-Zein/CMC-g-PDMDAAC can intelligently control drug release by adjusting monomer ratio and pH.There was no significant difference in toxicity between AVM@P-Zein/CMC-g-PDMDAAC and AVM.(2)In order to expand the application of Zein,the efficiency of nano-pesticides and realize the efficient utilization of pesticides,firstly,AVM@Zein-EGDE nano-pesticide was prepared by modifying Zein with EGDE and loading AVM.Secondly,Zein-EGDE is modified by CMC-g-P(HEMA-MMA)and loaded with AVM to obtain AVM@Zein-CMC nano-pesticide system.The results show that AVM@Zein-EGDE can be stably dispersed in water and their average particle size is162 nm.The average particle size of AVM@Zein-CMC is 188 nm.Compared with AVM@Zein-EGDE,AVM@Zein-CMC can improve the dispersion,the encapsulation efficiency increases from 65.97% to 77.05%,the anti-UV property is improved by about 5%,the adhesive property is improved by about 20%,and the sustained-release property is improved.In addition,Avm@Zein-CMC can intelligently control drug release by adjusting pH,and when pH increase from 3 to 11,the cumulative sustained release rate decreases gradually.The results of toxicity test shows that AVM@ZEIN-CMC could improve many properties of AVM,but had no effect on toxicity of AVM.