Quantum dot-based sensitive detection of disease specific exosome in serum

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

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Tumor-derived exosomes have emerged as promising cancer biomarkers due to their unique composition and functions. Herein, we report a stripping voltammetric immunoassay for the electrochemical detection of disease-specific exosomes using quantum dots as signal amplifiers. The assay involves three subsequent steps where bulk exosome populations are initially magnetically captured on magnetic beads by a generic tetraspanin antibody (e.g., CD9 or CD63) followed by the identification of disease-specific exosomes using cancer-related. Here, we used CdSe quantum dot (CdSeQD) functionalised-biotinylated HER-2 and FAM134B antibodies as breast and colon cancer markers. After magnetic washing and purification steps, acid dissolution of CdSeQDs and subsequent anodic stripping voltammetric quantification of Cd2+ were carried out at the bare glassy carbon working electrode. This method enabled sensitive detection of 100 exosomes per μL with a relative standard deviation (%RSD) of <5.5% in cancer cell lines and a small cohort of serum samples (n = 9) collected from patients with colorectal adenocarcinoma. We believe that our approach could potentially represent an effective bioassay for the quantification of disease-specific exosomes in clinical samples.
    Original languageEnglish
    Pages (from-to)2211-2219
    JournalAnalyst
    Volume142
    DOIs
    Publication statusPublished - 4 May 2017

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