Label-free impedimetric prostate cancer aptasensor with antifouling surface chemistry

P Jolly, Ján Tkáč, Peter Kasák, P Estrela

Research output: Contribution to conferencePosterpeer-review

Abstract

Prostate cancer (PCa) is the second most common cause of cancer related mortality among Western men. Hence, it is becoming very crucial to be early diagnosed with a high sensitivity and accuracy to preclude worsening of PCa. We here report the development of a biosensor for the analysis of Prostate Specific Antigen (PSA), a biomarker for PCa present in blood, using a PSA-specific DNA aptamer on polycrystalline gold electrodes. The main emphasis is on a clinical application where a specific and sensitive label free detection could be performed in blood samples using Electrochemical Impedance Spectroscopy (EIS) to test for a panel of PCa biomarkers.

A PSA biosensor was constructed by immobilizing a mixed self-assembled monolayer comprising of (1) 11-mercaptoundecanoic acid for covalent immobilization of amine terminated DNA aptamers and (2) betaine terminated thiol as an antifouling agent on a polycrystalline gold surface.
Upon incubation of PSA with the DNA aptamer-based biosensor a decrease of charge transfer resistance (Rct) was observed when using ferro-/ferri-cyanide redox probes in solution. The incubation with the control protein Human Serum Albumin does not show any significant changes in Rct. Unlike in other reports, we observe a decrease in Rct primarily due to the partial screening of the DNA charge by the large PSA molecule. A discussion is presented on the effect of the measurement buffer on the values and the sign of Rct variations upon DNA aptamer-PSA binding and the need to carefully select suitable measurement conditions.

Therefore, this proposed DNA aptamer-based biosensor is a promising, cost effective, label free and sensitive electrochemical detection platform for the detection of PSA in clinical samples using a simple surface chemistry.
Original languageEnglish
Publication statusUnpublished - 2014
Event24th Anniversary World Congress on Biosensors - Melbourne, Australia
Duration: 27 May 201430 May 2014

Conference

Conference24th Anniversary World Congress on Biosensors
CountryAustralia
CityMelbourne
Period27/05/1430/05/14

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