Electrogenerated chemiluminescence immunosensor for Bacillus thuringiensis Cry1Ac based on Fe3O4@Au nanoparticles

Area of Science:

• Biotechnology
• Analytical Chemistry
• Materials Science

Background:

• Cry1Ac is a key protein produced by Bacillus thuringiensis, widely used as a biopesticide.
• Accurate detection of Cry1Ac is crucial for monitoring its efficacy and environmental impact.
• Existing detection methods may lack the required sensitivity or convenience for field applications.

Purpose of the Study:

• To develop a highly sensitive electrochemiluminescence (ECL) immunosensor for the detection of Cry1Ac.
• To utilize core-shell Fe(3)O(4)@Au nanoparticles for enhanced antibody immobilization and signal amplification.
• To establish a convenient and renewable sensing platform for Cry1Ac analysis.

Main Methods:

• Fabrication of an ECL immunosensor using anti-Cry1Ac antibody immobilized on Fe(3)O(4)@Au nanoparticles.
• Formation of a sandwich-type immunocomplex involving Cry1Ac antigen and glucose-oxidase-labeled secondary antibody.
• Utilizing magnetic attraction to concentrate immune complexes on a magnet-controlled glass carbon electrode (GCE).
• Generating ECL signal through the reaction of luminol and hydrogen peroxide from enzymatic glucose oxidation.

Main Results:

• The developed immunosensor demonstrated high sensitivity for Cry1Ac detection.
• A wide linear detection range of 0–6 ng/mL was achieved for Bacillus thuringiensis Cry1Ac.
• An ultra-low detection limit of 0.25 pg/mL (S/N = 3) was obtained.
• The sensor exhibited excellent performance, being among the most sensitive available for Cry1Ac.

Conclusions:

• The Fe(3)O(4)@Au nanoparticle-based ECL immunosensor provides a highly sensitive and efficient platform for Cry1Ac detection.
• The magnetic manipulation and enzymatic amplification contribute to the sensor's superior performance.
• The sensor is easily renewable and convenient to use, offering practical advantages for Cry1Ac monitoring.