Charge reversible-natural light responsive nanoparticles enable targeted herbicide delivery and reduction of mammalian toxicity

Introduction

Mammalian health risks due to agrochemical exposure are becoming a global concern, increasingly. Long-term exposure to diquat (DQ) leads to multiple organ dysfunctions and increase mammal mortality. Despite existing mitigation strategies, including oxidative stress reduction and gut microbiota modulation, effective mitigation strategies for DQ poisoning remain elusive.

Objectives

Based on the dark gastrointestinal environment of mammals, a natural light-responsive DQ formulation was prepared, that effectively controls weeds and reduces toxicity to mammals.

Methods

By loading DQ onto bridged polysilsesquioxane (BPS) with charge reversal properties, a natural photo-responsive formulation of DQ@BPS was prepared. The physicochemical properties of BPS and DQ@BPS were studied with a series of characterization methods. Under natural light, the photo-controlled release properties of DQ@BPS were measured by molecular dynamics simulation. The control effect of DQ@BPS to barnyard grass was compared with that of DQ and a commercial formulation. A mouse model was used to study its toxicity. In addition, the safety of BPS in Chinese cabbage and DQ@BPS in earthworms were detected.

Results

We verified that DQ@BPS enable release DQ through natural light. BPS was reversed to a positive charge under natural light, and DQ was released via electrostatic repulsion, with a total release amount 7.27 times that under darkness. Compared with DQ, DQ@BPS ameliorated the liver and kidney damage while reducing body residues by over 10 times in mice, and showed effective control of barnyard grass. Furthermore, it was safe for earthworms, LC₅₀ > 1000 μg/cm², and the carrier itself was safe for Chinese cabbage.

Conclusion

Charge-reversible-natural light-responsive nanoparticles enable to deliver herbicide with reduced mammalian toxicity. This study provides a new photo-response mechanism in agrochemical delivery systems, offering a promising approach for reducing the toxicity of agrochemicals to mammals.