Dual-biomarker-based logic-controlled electrochemical diagnosis for prostate cancers

As single biomarker often has inadequate predictive value in clinical examination, we designed a dual-biomarker "AND" logic device that defines the concentration of prostate-specific antigen (PSA) and survivin mRNA as inputs and the increase in faradaic current from intercalation agent Co(phen) 33+ as output for prostate cancer (CaP) diagnosis on Au nano-film covered gold electrode surfaces. Primary capture antibody (Ab 1 ) was first immobilized on AuNP electrode, then while both PSA and survivin mRNA exist, current of Co(phen) 33+ observably increased due to the formation of dsDNA structure between survivin antisensoligonucleotide connected secondary detection antibody (Ab 2 ) and survivin mRNA. And when one of the two biomarkers was absent, no obvious current increment was found. Thus the designed "AND" logic gate greatly reduced the possibility of false-positive assay from non-cancerous prostate diseases such as prostatic hyperplasia and prostatitis in diagnosis of CaPs. © 2013 2013 Elsevier B.V. All rights reserved.