Glycerol-silica/chitosan conjugated self-assembled nano-flower framework for Herstulla thompsoni delivery with effectiveness in natural settings: Optimization and pilot scale production

Abstract

Hirsutulla thompsoni (HTS) is an entomopathogenic fungus (EPF), a secure and efficient substitute for synthetic insecticides. However, its susceptibility to degradation in conventional formulations limits its practical use for agricultural practices. In light of current setbacks, this work proposes using a glycerol-silica/chitosan nanoflower gel (NFG) as an efficient delivery system to enhance the efficacy of HTS. Inspired by glycerol-silica-chitosan conjugation, NFG self-assembles into flowers. The HTS-loaded nanoflower gel (HTS_NFG) features a flower-shaped morphology, an average size of 232 nm, and a zeta potential of +31.84mv. The laboratory-scale NFG is optimized with ingredients and process factors using multivariate principal component analysis (PCA), which progressed to pilot size 10 kg/shift. The notable foliage retention attributable to chitosan and lower contact angle was achievable on the hydrophobic leaf surface. The result of foliage retention and contact angle obtained showed a significant effect of NFG (p < 0.05). HTS_NFG was comparatively safer towards Chlorella spp. algae and Artemia salina, significant from other treatments (p < 0.05). Field efficacy evaluation demonstrated that the NFG was as effective as the reference sample against aphids. With its proven effectiveness, the NFG may be an aesthetic, sustainable, and feasible alternative for agro-production.