DNA Generated Electric Current Biosensor

Abstract

In addition to its primary function as a genetic material, deoxyribonucleic acid (DNA) is also a potential biologic energy source for molecular electronics. For the first time, we demonstrate that DNA can generate a redox electric current. As an example of this new functionality, DNA generated redox current was used for electrochemical detection of human epidermal growth factor receptor 2 (HER2), a clinically important breast cancer biomarker. To induce redox current, the phosphate of the single stranded DNA aptamer backbone was reacted with molybdate to form redox molybdophosphate precipitate and generate an electrochemical current of ∼16.8 μA/μM cm. This detection of HER2 was performed using a sandwich detection assay. A HER2 specific peptide was immobilized onto a gold electrode surface for capturing HER2 in buffer and serum. The HER2 specific aptamer was used as both ligand to bind the captured HER2 and to generate a redox current signal. When tested for HER2 detection, the electrochemical current generated by the aptasensor was proportional to HER2 concentration in the range of 0.01 to 5 ng/mL, with a current generated in the range of ∼6.37 to 31.8 μA/cm in both buffer and serum. This detection level is within the clinically relevant range of HER2 concentrations. This method of electrochemical signal amplification greatly simplifies the signal transduction of aptasensors, broadening their use for HER2 analysis. This novel approach of using the same aptamer as biosensor ligand and as transducer can be universally extended to other aptasensors for a wide array of biodetection applications. Moreover, electric currents generated by DNA or other nucleic acids can be used in molecular electronics or implanted devices for both power generation and measurement of output.

The Signal Amplification in Electrochemical Detection of Chloramphenicol Using Sulfonated Polyaniline‐chitosan Composite as Redox Capacitor

“…Currently, many novel strategies about signal amplification based on functional nanomaterials , enzyme‐signal , DNA self‐assembly and so on have been established for improving sensitivity of electrochemical detection. Among of them, a common method is to introduce a homogeneous chemical reaction coupled with electrode reaction for signal amplification.…”

Self-Assembled DNA Generated Electric Current Biosensor for HER2 Analysis

“…A detection limit of 0.047 pg/mL was obtained based on S/N = 3. Compared with other biosensors for HER2 detection, such as our previous work (detection range of 0.01–5 ng/mL, LOD = 5 pg/mL) and piezoelectric microcantilever sensors (detection range of 0.05–2 ng/mL), this aptasensor displays higher sensitivity and lower detection limit.…”

“…In previous work, we utilized an aptamer to generate redox electric current . The DNA current generation is based on the reaction of DNA phosphate groups bound to an electrochemical electrode with molybdate that can form redox molybdophosphate precipitate and generate electrochemical current. , Since the electric current depends on the amount of the DNA phosphate groups, in this work, by amplifying the amount of DNA, we fabricated an ultrasensitive electrochemical aptasensor for detection of HER2 based on the amplification of aptamer generated electric current by DNA self-assembly reaction.…”

The Potential Implementation of Biosensors for the Diagnosis of Biomarkers of Various Cancer

“…employed a specific aptamer of HER2 as a ligand and some other to give a redox electric signal. The reaction between the phosphate moieties in the aptamer and molybdate [86] produced this current. Overall, the aptasensor's electrochemical current was proportional to HER2 concentrations in the range of 0.015 ng/mL [87].…”