Antimould action of Ziram and IPBC loaded in functionalised nanogels against Aspergillus niger and Penicillium chrysogenum

Abstract

We explore the antimould action of zinc bis(dimethyldithiocarbamate) (Ziram) and 3-iodo-2-propynyl N-butylcarbamate (IPBC) encapsulated into nanogel particles with and without surface functionalization with a cationic polyelectrolyte, poly(diallyldimethylammonium chloride) (PDAC). The antimould nanocarriers were based on commercially available polyacrylic copolymeric nanogel. The antimould agents were loaded into the nanogel particles in their swollen state in alkaline media followed by collapsing of the nanogel particles at acidic pH. We treated Aspergillus niger and Penicillium chrysogenum cultures at different concentrations of the nanocarrier-loaded antimould agent. The effect of the surface charge of the antimould agent-loaded nanocarriers was examined in order to gain better understanding of how the electrostatic interaction of the nanocarrier with the cell walls of the mould hyphae and spores impacts its antimould action. Non-coated nanocarriers proved more efficient than PDAC-coated ones in their antimould action for both Ziram and IPBC formulations. Four different methods of application of the antimould nanocarriers were also explored. We found that the application method of the nanogel carrier is crucial for its efficiency and sustained antimould delivery. Pre-mixing the nanogel-formulated Ziram or IPBC with culture media generally produced much better antimould action. Such a strategy can potentially bypass this antimould resistance and lead to novel formulations with highly sustained antimould activity at similar concentrations of the antimould agent. These insights may lead to the development of more efficient antimould treatments at lower concentration of active agent for mould control with potentially substantial economic and environmental benefits.