Simultaneous multiplexed detection of exosomal microRNAs and surface proteins for prostate cancer diagnosis

Since the tumor is extremely heterogeneous, a single biomarker cannot reflect the exact symptoms of the disease or its stage. Exosomes are biomarker reservoirs that provide disease information with a high accuracy, especially when specific markers, including microRNAs (miRNAs) and proteins, are combined. However, currently available exosomal miRNA and protein detection methods are time consuming, expensive, and laborious. Meanwhile, simultaneous detection of an exosomal miRNA and protein in a single reaction is even more challenging. Thus, development of an efficient method for detecting multiple miRNAs and proteins in a single exosomal reaction is highly needed. Herein, to increase the value of using exosomes over other circulating biomarkers for prostate cancer (PCa) liquid biopsy, a method for simultaneous multiplexed in situ detection of exosomal miRNAs and proteins was developed. Exosomal miRNAs and surface proteins were simultaneously detected in captured exosomes with a high specificity, using nano-sized molecular beacons and fluorescent dye-conjugated antibodies. The method allowed the quantitative analysis of various disease-specific miRNAs and surface proteins in PCa cell-derived exosomes in a single exosomal reaction. Overall, simultaneous multiplexed in situ detection of exosomal miRNAs and surface proteins can be developed as a simple, cost-effective, non-invasive liquid biopsy method for diagnosing PCa.