Fabrication of ultrafine sporopollenin particles and its application as pesticide carrier

Abstract

Control release formulation is of great interest to pesticide researchers due to its programmable release of active ingredients with low environmental risk. The carrier is a dominant factor affecting the performance of the preparation. In this work, a copper-based fungicide is developed using plant sporopollenin materials as a control release carrier. Although sporopollenin is regarded as the toughest natural material, sporopollenin was broken down into nano- and micro- particles along with the modified surface chemistry by a facile oxidation treatment. The surface chemistry of sporopollenin is characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS) and Boehm titration. The resulting ultrafine sporopollenin particles (USPs) show a high copper(II) loading capacity of 435 mg/g, owing to the electrostatic effect. Furthermore, copper(II) can be released from copper(II)–sporopollenin complex (Cu-USPs) in a pH-dependent manner. As a proof of concept, Cu-USPs show very promising activity against a plant-specific pathogen-Pectobacterium carotovorum. Overall, this paper shed light on developing sporopollenin-derived functional materials for pesticide delivery.