Reusable Electrochemical Sensing Platform for Highly Sensitive Detection of Small Molecules Based on Structure-Switching Signaling Aptamers

Abstract

Aptamers are nucleic acids that have high affinity and selectivity for their target molecules. A target may induce the structure switching from a DNA/DNA duplex to a DNA/target complex. In the present study, a reusable electrochemical sensing platform based on structure-switching signaling aptamers for highly sensitive detection of small molecules is developed using adenosine as a model analyte. A gold electrode is first modified with polytyramine and gold nanoparticles. Then, thiolated capture probe is assembled onto the modified electrode surface via sulfur-gold affinity. Ferrocene (Fc)-labeled aptamer probe, which is designed to hybridize with capture DNA sequence and specifically recognize adenosine, is immobilized on the electrode surface by hybridization reaction. The introduction of adenosine triggers structure switching of the aptamer. As a result, Fc-labeled aptamer probe is forced to dissociate from the sensing interface, resulting in a decrease in redox current. The decrement of peak current is proportional to the amount of adenosine. The present sensing system could provide both a wide linear dynamic range and a low detection limit. In addition, high selectivity, good reproducibility, stability, and reusability are achieved. The recovery test demonstrates the feasibility of the designed sensing system for an adenosine assay.

Detection of Protein–Aptamer Interactions by Means of Electrochemical Indicators and Transverse Shear Mode Method

“…Recently, ferrocene (Fc)-modified aptamers were used for the detection of adenosine (Wu et al, 2007). The thiolated aptamers were chemisorbed on a gold electrode modified with polytyramine and gold nanoparticles.…”

Review: <i>Biosensors for the detection of Escherichia coli</i>

“…Aptamers can form selective and re-useable sensors, and can form efficient immobilisations and high-density monolayers that are critical to miniaturised systems (Bang et al, 2005;Wu et al, 2007). …”

The Clinical Application of Aptamers: Future Challenges and Prospects

“…Unlike antibodies, which suffer from permanent degradation, an aptamer-immobilized ELISA system can be easily reused for different protocols after the target has been unbound. In one experiment, for example, temperature change was used to regenerate aptamers more than 40 times, and 90 % of these aptamers were able to refold into their original configuration [20].…”