A general strategy for the efficient utilization of Microbiocide by using polyacrylic acid sodium as a flexible framework material.

Introduction: Copper sulfide nanoparticles are ideal carrier materials for the preparation of controlled release nano-systems that can effectively improve the utilization efficiency and environmental safety of microbicides because of their excellent antimicrobial activity, low environmental toxicity, and controllable structure.

Objectives: This study aims to elucidate the general rules of loading and release of drugs in pH-responsive nano-delivery systems based on CuS NPs and develop a general strategy for efficient utilization of microbicide and sustainable plant disease management.

Methods: Three microbicide-loaded copper sulfide nanoparticles (Microbicide@PAS-CuS NPs) were fabricated via a one-pot route by using polyacrylic acid sodium (PAS) as a flexible framework carrier material and berberine sulfate (BBR), bronopol (BNP), and kasugamycin (KSM) as the loaded microbicides. The physicochemical properties, bioactivity, effective duration, genotoxicity, and plant safety of the obtained Microbicide@PAS-CuS NPs were characterized and evaluated systematically.

Results: The results indicated that the encapsulation efficiency and microbicide loading capacity of Microbicide@PAS-CuS NPs increased with decreasing LogP values of the microbicides. The obtained Microbicide@PAS-CuS NPs were regular spherical nanoparticles with a uniform particle size, good dispersion stability, and high microbicide loading rate (ranging from 21.36 to 37.50 %) and could respond to the acidic microenvironments associated with pathogen infection to control release the microbicide. Because KSM and BNP were loaded into the channels of nanocapsules formed by incorporating Cu and S into PAS nanomicells, their photostabilities were increased by 15.11 and 2.84 times, respectively. Compared with the microbicide alone, the Microbicide@PAS-CuS NPs not only had better antimicrobial activity with a longer effective duration but also improved the safety of both the microbicide and Cu to plants.

Conclusion: This study provides a universal strategy to increase the utilization efficiency and environmental safety of microbicides. Microbicide@PAS-CuS NPs have promising applications as novel stimuli-responsive controlled release nano-delivery systems.