Quantitative Electrochemical DNA Microarray on a Monolith Electrode with Ten Attomolar Sensitivity, 100 % Specificity, and Zero Background

Shobana Raghunath, Abhijeet Prasad, Rahul Tevatia, Jillian R. Gunther, Santanu Roy, Sunil Krishnan, Ravi F. Saraf

Research output: Contribution to journalArticle

5 Scopus citations


Circulating microRNA are promising diagnostic and prognostic biomarkers of disease in quantitative blood tests. A label-free, PCR-free, electrochemical microarray technology on a monolith electrode is described, with 10 attomolar (aM) sensitivity and responsiveness to binding of <1 zeptomole of target to immobilized ssDNA probes with zero background. Specificity is 100 % in a mixture with five nonspecific miRNA each with a 103-fold higher concentration. Direct measurement on plasma-derived miRNA without cDNA conversion and PCR demonstrated multiplexing and near-ideal quantitative correlation with an equivalent pure sample. The dynamic range is a target concentration ranging from 10−2 to 103 femtomolar (fM). This PCR-free novel technology can be applied as a test for cancer diagnosis/prognosis to detect 103 copies of a miRNA sequence in RNA extracted from 100 μL of plasma.

Original languageEnglish (US)
Pages (from-to)429-433
Number of pages5
Issue number3
StatePublished - Feb 2018



  • DNA sequencing
  • blood test
  • cancer diagnosis
  • electrochemical analysis
  • microRNA
  • microarray

ASJC Scopus subject areas

  • Catalysis
  • Electrochemistry

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