Enhancing insecticidal efficacy of Bacillus thuringiensis Cry1Ab through pH-sensitive encapsulation.

Area of Science:

• Agricultural Science
• Materials Science
• Biotechnology

Background:

• Bacillus thuringiensis (Bt) insecticidal proteins face environmental degradation.
• Nanotechnology offers potential solutions for enhancing protein stability.
• Cry1Ab protein is crucial for controlling lepidopteran pests.

Purpose of the Study:

• To evaluate the protective effects of Pickering emulsions stabilized by Cu²⁺-SQDs/S-CN nanocomposites and GO nanosheets on Cry1Ab protein.
• To assess the pH-sensitive release mechanism for enhanced pesticidal activity.
• To determine the impact of UV light and temperature on encapsulated Cry1Ab.

Main Methods:

• Preparation of Pickering emulsions stabilized by Cu²⁺-SQDs/S-CN nanocomposites and GO nanosheets.
• Incorporation of a pH-sensitive polymer for controlled release.
• Exposure of encapsulated and unprotected Cry1Ab to UV light and heat (40°C).
• SDS-PAGE analysis and bioassays with *Ostrinia nubilalis* larvae.

Main Results:

• Pickering emulsions effectively encapsulated solubilized Cry1Ab.
• Encapsulation provided structural protection against UV degradation.
• UV and temperature treatments showed reduced degradation rates for encapsulated Cry1Ab.
• Bioassays confirmed enhanced residual activity and pesticidal efficacy up to 12-fold after UV treatment.

Conclusions:

• Pickering emulsions stabilized by specific nanomaterials are effective for Cry1Ab encapsulation.
• pH-sensitive encapsulation enhances the structural integrity and toxicity of Cry1Ab.
• Nanomaterial-based encapsulation improves the environmental stability and efficacy of Bt insecticides.