Preparation of UV-responsive hydrogels based on nanocellulose and their utilization in fungicide delivery

Environmental responsive fungicide carrier systems can realize the on-demand intelligent delivery of drugs through different stimulus reactions, improve the utilization rate of fungicides, and effectively prevent and control pests. Nanocellulose has gradually become an important carrier material in the field of fungicide-controlled release because of its many excellent characteristics, such as no biotoxicity, high specific surface area, biodegradability, and good biocompatibility. In this paper, we construct a pH- and UV-responsive cellulose-based hydrogel (ASB@AZO-CNC) with controllable and sustained release performance based on UV-sensitive molecular chelated cellulose nanocrystals (CNCs), and azoxystrobin (ASB) was used as a model fungicide. The drug release performance and antibacterial activity of the cellulose-based hydrogels were investigated. The drug release rate of hydrogels at pH 5.5 reaches up to 89.44%, while the hydrogels subjected to UV irradiation exhibit a 6.4-fold increase compared to those without light exposure, and the antibacterial activity of the hydrogel is directly proportional to the drug concentration. This method can effectively reduce fungicide loss and reduce the pollution of fungicides in an ecological environment, which has broad application prospects in agricultural production. A stimuli-responsive hydrogel for fungicide delivery based on UV-sensitive molecular (AZO)-conjunct CNCs is successfully prepared.