Label-Free Impedimetric Aptasensor with Antifouling Surface Chemistry: a Prostate Specific Antigen Case Study

Pawan Jolly, Nello Formisano, J Tkac, P Kasak, Christopher Frost, Pedro Estrela

Research output: Contribution to journalArticle

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Abstract

We here report the development of an aptamer based biosensor for the investigation of prostate specific antigen (PSA), a biomarker found in blood for prostate cancer (PCa), using electrochemical impedance spectroscopy (EIS). The study concentrates on a clinical application where a specific and sensitive label-free detection could be performed in real blood samples using EIS. Two types of PSA aptasensor were fabricated by immobilizing (i) a self-assembled monolayer comprising of 6-mercaptohexanol (MCH) and thiolated-DNA aptamer and (ii) 11-mercaptoundecanoic acid for covalent immobilization of amine terminated DNA aptamers and sulfo-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 due to the partial screening of the DNA aptamer charge by PSA. Thiol terminated sulfo-betaine based sensors can detect PSA levels lower than 1 ng/ml. Validation of the aptasensor is provided by surface plasmon resonance measurements. Sulfo-betaine moiety also prevents any significant non-specific binding of the control protein human serum albumin (HSA) as compared to high non-specific binding with MCH-based sensors. A debate is presented on the effect of the measurement buffer on the values and the direction of Rct changes on the aptasensors and the need to cautiously select suitable measurement conditions in order to obtain reliable results. This is the first report to date where a DNA aptamer-based biosensor was developed using thiol-terminated sulfo-betaine, which is a simple surface chemistry for the development of promising, cost-effective, label-free and sensitive electrochemical detection platforms for a range of analytes.
Original languageEnglish
Pages (from-to)306-312
Number of pages7
JournalSensors and Actuators B: Chemical
Volume209
Early online date21 Nov 2014
DOIs
Publication statusPublished - 31 Mar 2015

Fingerprint

Nucleotide Aptamers
antifouling
Betaines
antigens
Prostate-Specific Antigen
Antigens
Betaine
Surface chemistry
betaines
Labels
DNA
deoxyribonucleic acid
chemistry
bioinstrumentation
Sulfhydryl Compounds
thiols
Biosensors
Electrochemical impedance spectroscopy
blood
Blood

Keywords

  • DNA aptamers
  • Prostate specific antigen
  • Electrochemical impedance spectroscopy
  • Antifouling properties

Cite this

Label-Free Impedimetric Aptasensor with Antifouling Surface Chemistry: a Prostate Specific Antigen Case Study. / Jolly, Pawan; Formisano, Nello; Tkac, J; Kasak, P; Frost, Christopher; Estrela, Pedro.

In: Sensors and Actuators B: Chemical, Vol. 209, 31.03.2015, p. 306-312.

Research output: Contribution to journalArticle

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