Thermo-responsive polysulfobetaine beads crosslinked with biodegradable alginates for controlled release of agricultural pesticide

Abstract

The rise in global food demand and the loss in crop production by pests highlight the need for efficient pesticide delivery systems. Stimuli-responsive degradation with thermoresponsive polymers is a promising platform that offers the controlled release of pesticides. Here, we report the development of millimeter-sized thermoresponsive beads (m-beads) composed of a zwitterionic polysulfobetaine exhibiting upper critical solution temperature (UCST) behavior, crosslinked with biodegradable alginate via supramolecular ionic interactions with calcium ions in water. The fabricated m-beads are capable of encapsulating fluorescein and glufosinate ammonium pesticide with encapsulation efficiency greater than 99%. Promisingly, they exhibit enhanced release with an increasing amount of alginate in m-beads as well as at a temperature above the UCST. This work highlights the potential of UCST-type polysulfobetaine-based m-beads as a smart delivery platform, offering environmentally-triggered release of pesticides.