Colorimetric engineered immunoprobe for the detection and quantification of microcystins

Area of Science:

• Environmental Science
• Biotechnology
• Analytical Chemistry

Background:

• Microcystins (MCs) are potent heptapeptide toxins produced by cyanobacteria, posing a global threat to aquatic ecosystems and human health.
• Existing detection methods for MCs, including antibody-based assays, face challenges in specificity, efficiency, and adaptability for field use.

Purpose of the Study:

• To develop a novel, highly specific, and efficient detection method for microcystins using recombinant antibody technology.
• To create a bivalent colorimetric immunoprobe (scFv-AP) for direct competitive enzyme immunoassay (ELISA) of MCs.

Main Methods:

• Production of a recombinant antibody fragment (single-chain variable fragment, scFv) fused to alkaline phosphatase (AP) from Escherichia coli.
• Expression of the scFv-AP fusion protein in the periplasm of recombinant bacteria for direct use without purification.
• Development of a direct competitive enzyme immunoassay utilizing the scFv-AP probe for MC detection.

Main Results:

• The developed scFv-AP immunoprobe specifically recognized a common motif shared by all microcystins.
• The direct competitive enzyme immunoassay enabled sensitive detection of MCs without the need for extensive purification steps.
• The recombinant antibody technology provided a robust and adaptable platform for MC detection.

Conclusions:

• Recombinant antibody technologies offer significant advantages over traditional chemical cross-linking methods for developing diagnostic tools.
• The scFv-AP fusion protein is a promising tool for the specific and efficient detection of microcystins in aquatic environments.
• This approach holds potential for in-situ water sample analysis and broader applications in toxin detection.