pH-sensitive thiamethoxam nanoparticles based on bimodal mesoporous silica for improving insecticidal efficiency

Area of Science:

• Materials Science
• Nanotechnology
• Environmental Science

Background:

• Pesticides like thiamethoxam (Thi) face challenges with photolysis and stability.
• Developing controlled-release formulations is crucial for effective pest management and reduced environmental impact.

Purpose of the Study:

• To synthesize and characterize pH-sensitive thiamethoxam-loaded bimodal mesoporous silica nanoparticles (P/Thi-NN-BMMs).
• To evaluate the controlled-release properties, stability, and insecticidal efficacy of the developed nanoparticles.

Main Methods:

• Synthesis of pH-sensitive nanoparticles using bimodal mesoporous silica (BMMs) as a carrier via free radical polymerization.
• Characterization using X-ray powder diffraction, N2-sorption, and thermogravimetric analysis.
• Assessment of pH-dependent release, anti-photolysis, storage stability, and relative toxicity against peach aphids.

Main Results:

• Synthesized P/Thi-NN-BMMs nanoparticles (approx. 891.7 nm) with a loading rate of 25.2%.
• Demonstrated excellent anti-photolysis and storage stability, with significant pH sensitivity.
• Observed higher Thi release rates at pH 10.0 compared to pH 7.4 and pH 3.0, following Weibull model kinetics.
• P/Thi-NN-BMMs exhibited 1.44 times higher relative toxicity against peach aphids than commercial thiamethoxam.

Conclusions:

• The developed pH-sensitive P/Thi-NN-BMMs nanoparticles provide a stable and effective controlled-release system for thiamethoxam.
• These nanoparticles show enhanced insecticidal activity and potential for improved pest control strategies.
• This approach offers a promising avenue for environmentally conscious pest management solutions.