Biodegradable redox sensitive chitosan based microgels for potential agriculture application

In this work, we report redox sensitive, 2,3-dihydroxybenzoic acid (DH) functionalized chitosan/stearic acid microgels (DH-ChSt MGs) for controlled delivery of insecticide and capturing of heavy metal ions. DH-ChSt MGs (approximate to 146 nm) are prepared by disulfide crosslinking of -SH functionalized chitosan and stearic acid rendering them biodegradable. DH-ChSt MGs exhibit high loading (approximate to 8 %) and encapsulation (approximate to 85 %) efficiency for imi-dacloprid insecticide, and offer its prolonged release (approximate to 75 % after 133 h) under reducing conditions. Func-tionalization with DH provides enhanced foliar adhesion on pea leaves. DH-ChSt MGs also bind Fe3+ very efficiently due to the strong chelation of Fe3+ by DH, offering the opportunity of supplying Fe3+ nutrient for plant care. MTT assay results using different cells confirm that DH-ChSt MGs are nontoxic up to the experimental concentration of 120 mu g/mL. Additionally, reduced DH-ChSt MGs having free thiol groups are also capable of binding heavy metal ions, thus presenting the reported formulation as a promising platform for agriculture application.

Automated summary

In this study, redox-sensitive DH-ChSt MGs were developed for controlled release of insecticide and capturing heavy metal ions. The DH-ChSt MGs exhibited high loading and encapsulation efficiency for imi-dacloprid insecticide, and prolonged release under reducing conditions. DH-ChSt MGs also showed enhanced foliar adhesion and efficient binding of Fe3+. MTT assay confirmed the non-toxicity of DH-ChSt MGs, and their capability to bind heavy metal ions makes them a promising platform for agriculture application.