Renewable Plant Oil-Based Molecularly Imprinted Polymers as Biopesticide Delivery Systems

New bio-based molecularly imprinted polymers (MIPs) were synthesized as biopesticide delivery systems by free radical polymerization using a functional monomer and a vegetable oil-derived cross-linker, epoxidized soybean oil acrylate (ESOA). Resveratrol, a polyphenol with antifungal activity against several phytopathogens, was employed in this study as a model biopesticide. 4-Vinylpyridine (4VP) and 1-vinylimidazole (1VI) were the best functional monomers for resveratrol imprinting, as determined by nuclear magnetic resonance (NMR) interaction studies and batch binding experiments. ESOA-based MIPs showed comparable specificity, high affinity, and selectivity for resveratrol when compared to MIPs prepared with the traditional cross-linker ethylene glycol dimethacrylate (EGDMA). Bio-based MIP particles were also produced by emulsion polymerization, a greener method needing less organic solvent than precipitation polymerization. Bio-based MIPs could release resveratrol in aqueous medium and were sensitive to a fungal lipase from Candida rugosa, suggesting an alteration of the polymeric matrix by this lipase. Resveratrol-loaded MIPs were used as drug delivery systems for the inhibition of the phytopathogen Sclerotinia sclerotiorum in solid and liquid media. MIPs prepared with 4VP and ESOA exhibited high inhibitory effects. This work demonstrates the feasibility of MIPs synthesis with a vegetable oil-derived cross-linker, and the resulting material represents a promising sustainable pest control agent delivery system for crop protection.