Three-mode electrochemical sensing of ultralow MicroRNA levels

Mahmoud Labib, Nasrin Khan, Shahrokh M. Ghobadloo, Jenny Cheng, John Paul Pezacki, Maxim V. Berezovski*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

191 Scopus citations


MicroRNAs (miRNAs) are an emerging class of biomarkers that are frequently deregulated in cancer cells and have shown great promise for cancer classification and prognosis. In this work, we developed a three-mode electrochemical sensor for detection and quantitation of ultralow levels of miRNAs in a wide dynamic range of measured concentrations. The sensor facilitates three detection modalities based on hybridization (H-SENS), p19 protein binding (P-SENS), and protein displacement (D-SENS). The combined three-mode sensor (HPD-SENS) identifies as low as 5 aM or 90 molecules of miRNA per 30 μL of sample without PCR amplification, and can be operated within the dynamic range from 10 aM to 1 μM. The HPD sensor is made on a commercially available gold nanoparticles-modified electrode and is suitable for analyzing multiple miRNAs on a single electrode. This three-mode sensor exhibits high selectivity and specificity and was used for sequential analysis of miR-32 and miR-122 on one electrode. In addition, the H-SENS can recognize miRNAs with different A/U and G/C content and distinguish between a fully matched miRNA and a miRNA comprising either a terminal or a middle single base mutation. Furthermore, the H- and P-SENS were successfully employed for direct detection and profiling of three endogenous miRNAs, including hsa-miR-21, hsa-miR-32, and hsa-miR-122 in human serum, and the sensor results were validated by qPCR.

Original languageEnglish (US)
Pages (from-to)3027-3038
Number of pages12
JournalJournal of the American Chemical Society
Issue number8
StatePublished - Feb 27 2013
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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