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Updated: Nov 20, 2025

Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
Allosteric Regulation of DNA Circuits Enables Minimal and Rapid Biosensors of Small Molecules
Alan F Rodríguez-Serrano1, I-Ming Hsing1
1Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Abstract:
Detection of environmental pollutants is crucial to safeguard ecological and public health. Here, we report a modular biosensing approach for the detection of contaminants based on the regulation of a minimal DNA signal amplifier and transducer circuit by allosteric transcription factors and their cognate ligands. We leverage the competition between allosteric proteins and an endonuclease to modulate cascade toehold-mediated strand displacement reactions, which are triggered in the presence of specific effectors and sustained by the endonuclease. We built two optical biosensors for the detection of tetracyclines and macrolides in water using repressors TetR and MphR, respectively. We demonstrate that our minimal, fast, and single-step biosensors can successfully detect antibiotics in nanomolar levels and apply them to report the presence of spiked-in antibiotics in water samples in a matter of minutes, suggesting great potential for monitoring of water contaminants.
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