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Browsing Chemistry by Subject "Aspergillus niger"
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Item Open Access ANTIMOULD ACTION OF ZIRAM AND IPBC LOADED IN FUNCTIONALISED NANOGELS AGAINST ASPERGILLUS NIGER AND PENICILLIUM CHRYSOGENUM(Materials Advances, 2022) Raimond, Laurine; Halbus, Ahmed F.; Athab, Zahraa H.; Paunov, Vesselin N.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.Item Open Access ENHANCED ANTIMOULD ACTION OF SURFACE MODIFIED COPPER OXIDE NANOPARTICLES WITH PHENYLBORONIC ACID SURFACE FUNCTIONALITY(Biomimetics, 2021-03-15) Henry, Patricia; Halbus, Ahmed F.; Athab, Zahraa H.; Paunov, Vesselin N.Antimould agents are widely used in different applications, such as specialty paints, building materials, wood preservation and crop protection. However, many antimould agents can be toxic to the environment. This work aims to evaluate the application of copper oxide nanoparticles (CuONPs) surface modified with boronic acid (BA) terminal groups as antimould agents. We developed CuONPs grafted with (3-glycidyloxypropyl) trimethoxysilane (GLYMO), coupled with 4-hydroxyphenylboronic acid (4-HPBA), which provided a strong boost of their action as antimould agents. We studied the antimould action of the 4-HPBA-functionalized CuONPs against two mould species: Aspergillus niger (A. niger) and Penicillium chrysogenum (P. chrysogenum). The cis-diol groups of polysaccharides expressed on the mould cell walls can form reversible covalent bonds with the BA groups attached on the CuONPs surface. This allowed them to bind strongly to the mould surface, resulting in a very substantial boost of their antimould activity, which is not based on electrostatic adhesion, as in the case of bare CuONPs. The impact of these BA-surface functionalized nanoparticles was studied by measuring the growth of the mould colonies versus time. The BA-functionalized CuONPs showed significant antimould action, compared to the untreated mould sample at the same conditions and period of time. These results can be applied for the development of more efficient antimould treatments at a lower concentration of active agent with potentially substantial economic and environmental benefits