title: Label-free electrochemical detection of prostate-specific antigen based on nucleic acid aptamer.
abstract: We report a label-free aptasensor to make direct detection of prostate specific antigen (PSA, a biomarker of prostate cancer) using a quinone-containing conducting copolymer acting as redox transducer and grafting matrix for immobilization of the short aptamer strands. It is shown that capture of PSA generates a current decrease (signal-off) measured by Square Wave Voltammetry. This current decrease is specific for PSA above a limit of quantification in the ng mL(-1) range. The change in current is used to determine the PSA-aptamer dissociation constant K(D), of ca. 2.6 nM. To consolidate the proof of concept, a heterogeneous competitive exchange with a complementary DNA strand which breaks PSA-aptamer interactions is studied. This double-check followed by a current increase provides full assurance of a perfectly specific recognition.
authors.affiliation: Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
authors.forename: M
authors.initials: M
authors.lastname: Souada
authors.affiliation: Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France. Electronic address: piro@univ-paris-diderot.fr.
authors.forename: B
authors.initials: B
authors.lastname: Piro
authors.affiliation: Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
authors.forename: S
authors.initials: S
authors.lastname: Reisberg
authors.affiliation: Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
authors.forename: G
authors.initials: G
authors.lastname: Anquetin
authors.affiliation: Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
authors.forename: V
authors.initials: V
authors.lastname: Noël
authors.affiliation: Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
authors.forename: M C
authors.initials: MC
authors.lastname: Pham
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D006801:Humans; D008297:Male; D009841:Oligonucleotides / Q000737:chemistry; D017430:Prostate-Specific Antigen / Q000737:chemistry / Q000302:isolation & purification*; D011471:Prostatic Neoplasms / Q000175:diagnosis*
chemical_list: D052157:Aptamers, Nucleotide; D009841:Oligonucleotides; D017430:Prostate-Specific Antigen
keywords: Aptamer; Electrochemical aptasensor; Label-free detection; Prostate-specific antigen (PSA)