Amorphous cellulose nano-pesticide with hairball structure to overcome sudden release difficulty

Refining renewable cellulose biomass to construct intelligent pesticide delivery systems has been attractive but hampered by low encapsulation efficiency and sudden release disadvantages. Unlike prevalent microcapsule that cellulose was constructed as the wall material thus sudden release was usually triggered trough the cracking effect, this work proposed the facile hairball model for homogenously pesticide loading trough cellulose amorphization followed by self-assembly technique route with the goal of sustained and pesticide multiple-responsive release. Cellulose amorphization through facile acetylation allowed the self-assembly process for amorphous cellulose nanosphere (ACNS) fabrication with controllable size from 65.1 to 217.6 nm, while also simultaneously facilitating avermectin (AVM) incorporation with high encapsulation efficiency of 92.2 %. The enhanced hydrophobic property also contributed to the adhesion between AVM@ACNS and crop leaves with enhanced rainwater washout resistance. The volumetric expansion and porosity increase of AVM@ACNS was led to temperature-responsive release of 91.0 %. Hydrolysis layer-by-layer at alkaline condition of AVM@ACNS was led to the pH-responsive release of 90.0 %. The β-1,4-glycosidic bonds cleavage of AVM@ACNS was led to cellulase-responsive release of 90.9 %. This work proposed a facile cellulose nano-pesticide fabrication strategy with multiple -responsive release functionality, with the new technique concept to address the sudden release challenge in the nano-pesticide field.