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Updated: Jun 24, 2026

Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
Supramolecular cocaine-aptamer complexes activate biocatalytic cascades
Ronit Freeman1, Etery Sharon, Ran Tel-Vered
1Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
This study presents novel aptamer-based biosensors for cocaine detection. These systems utilize enzyme cascades to generate detectable signals in response to cocaine binding, offering a biomimetic approach for diagnostics.
Area of Science:
- Biochemistry
- Molecular Biology
- Biosensor Technology
Background:
- Aptamers are nucleic acid sequences with high specificity for target molecules.
- Enzyme cascades offer signal amplification for biosensing applications.
- Biomimetic systems aim to replicate biological functions for technological applications.
Purpose of the Study:
- To develop novel aptamer-based biosensors for cocaine detection.
- To engineer enzyme-aptamer conjugates for cocaine-specific signal generation.
- To explore biomimetic prototypes for systems biology applications.
Main Methods:
- Fragmentation of an anti-cocaine aptamer into two functional nucleic acids.
- Tethering of nucleic acid (1) with aminoethyl nicotinamide adenine dinucleotide (amino-NAD+) or horseradish peroxidase (HRP).
- Functionalization of nucleic acid (2) with alcohol dehydrogenase (AlcDH) or glucose oxidase (GOx).
- Formation of supramolecular complexes in the presence of cocaine.
- Activation of biocatalytic cascades for signal generation.
Main Results:
- Formation of a supramolecular NAD+/AlcDH/cocaine-aptamer complex, activating ethanol oxidation in the presence of cocaine.
- Formation of a GOx/HRP/cocaine-aptamer complex, activating a glucose oxidation cascade yielding H2O2.
- H2O2 generated from glucose oxidation activates HRP-catalyzed oxidation of ABTS(2-).
- Demonstration of cocaine-dependent activation of two distinct biocatalytic systems.
Conclusions:
- Developed novel aptamer-based biosensor systems for cocaine detection.
- Engineered enzyme-aptamer conjugates that activate biocatalytic cascades upon cocaine binding.
- These systems serve as biomimetic prototypes with potential applications in systems biology and diagnostics.
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