Hydrogel-based hybridization chain reaction (HCR) for detection of urinary exosomal miRNAs as a diagnostic tool of prostate cancer

Although urinary exosomal microRNAs (miRNAs) have recently emerged as potential biomarkers, clinical applications are still limited due to their low concentration in small volumes of clinical samples. Therefore, the development of a non-invasive, specific diagnostic tool, along with profiling exosomal miRNA markers from urine, remains a significant challenge. Here, we present hydrogel-based hybridization chain reaction (HCR) for multiplex signal amplification to detect urinary exosomal miRNAs from human clinical samples. We succeeded in identifying small amounts (similar to amol) of exosomal miRNAs from 600 mu L of urine with up to similar to 35-fold amplification and enhanced detection limits by over an order of magnitude for two miRNA biomarker candidates, hsa-miR6090 and hsa-miR-3665. Furthermore, we proposed ratiometric analysis without requiring normalization to a reference miRNA and validated the clinical diagnostic potential toward differentiating prostate cancer patients from healthy controls. Our hydrogel-based HCR could serve as a new diagnostic platform for a non-invasive liquid biopsy before burdensome tissue biopsy of various diseases, including prostate cancer screening, complementing the PSA test.

Automated summary

Urinary exosomal miRNAs are potential biomarkers, but limited by low concentration and small volume. Hydrogel-based HCR technique shows high amplification and enhanced detection limits for miRNA in urine samples, with potential for clinical diagnosis applications in differentiating prostate cancer patients from healthy controls.