Development of a sensitive multiplexed open circuit potential system for the detection of prostate cancer biomarkers

Lai Chun Caleb Wong, Pawan Jolly, Pedro Estrela

Research output: Contribution to journalArticlepeer-review

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We report the development of a sensitive label-free, cost-effective detection system with simultaneous multi-channel measurement of open circuit potential (OCP) variations for the detection of prostate specific antigen (PSA). We demonstrate a significant increase of 600 times in the sensitivity as compared to the reported literature. To accurately measure OCP variations, a complete monolithic field-effect transistor (FET)-input ultra-low input bias current instrumentation amplifier is used to form the electronic circuit to measure the variation between a working electrode and a reference electrode. This amplifier electronic system setup provides a differential voltage measurement with high input impedance and low input bias current. Since no current is applied to the electrochemical system, a true and accurate measurement of the variation can be performed. This is the first report on the use of DNA aptamers with an OCP system where we employed a DNA aptamer against PSA. An optimised ratio of anti-PSA DNA aptamer with 6-mercapto-1-hexanol (MCH) was used to fabricate the aptasensor using gold electrodes. The electrodes are hosted in a cell with an automated flow system. A wide range of concentrations of PSA (0.1 to 100 ng/mL) were injected through the system. The sensor could potentially differentiate 0.1 ng/mL PSA from blank measurement, which is well below the required clinical range (>1 ng/mL). The sensor was also challenged with 4% human serum albumin and human kallikrein2 as control proteins where the sensor demonstrated excellent selectivity. The developed system can be further generalised to various other targets using specific probes.

Original languageEnglish
Pages (from-to)701-706
Number of pages6
Issue number2
Early online date1 Apr 2017
Publication statusPublished - 1 Jun 2018


  • Biosensors


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