An amplification-free electrochemical detection of exosomal miRNA-21 in serum samples

Kseniia Boriachek, Muhammad Umer, Md Nazmul Islam, Vinod Gopalan, Alfred K. Lam, Nam Trung Nguyen, Muhammad J.A. Shiddiky

Research output: Contribution to journalArticlepeer-review

104 Citations (Scopus)


Recent evidence suggests that small non-coding RNAs such as microRNA (miRNA) encapsulated in exosomes represent an important mechanism of communication between the cells. Exosomal miRNAs play an important role in carcinogenesis via enhancing the cell to cell communication and targeting the cell growth molecular pathways which in turn facilitate metastasis in cancers. Despite progressive advances, the current methods for the exosomal miRNA detection mostly rely on labor-intensive sequencing approaches which are often prone to amplification bias and require costly and bulky equipment. Herein, we report an electrochemical approach for the detection of cancer-derived exosomal miRNAs in human serum samples by selectively isolating the target miRNA using magnetic beads pre-functionalized with capture probes and then directly adsorbing the targets onto a gold electrode surface. The level of adsorbed miRNA is detected electrochemically in the presence of an [Fe(CN)6]4-/3- redox system. This method enabled an excellent detection sensitivity of 1.0 pM with a relative standard deviation (%RSD) of <5.5% in cancer cells and serum samples (n = 8) collected from patients with colorectal adenocarcinoma (CRC). We believe that our approach could be useful in clinical settings for the quantification of exosomal miRNA in cancer patients.
Original languageEnglish
Pages (from-to)1662-1669
Number of pages8
Issue number7
Early online date12 Feb 2018
Publication statusPublished - 07 Apr 2018


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