A facile optical fiber-embedded microfluidic biochip for rapid and sensitive detection of microRNA-let-7a in serum

A novel hybridization chain reaction (HCR) powered optical fiber-embedded microfluidic biochip (HCR-FMB) has been constructed for ultrafast and sensitive detection of lethal-7a (let-7a) in serum. By integrating HCR, fluorescence energy resonant transfer, and evanescent wave fluorescence principle, the HCR-FMB enables detecting let-7a with satisfactory limit of detection of 100.0 pM within 6 min at room temperature, and demonstrates excellent specificity. The HCR-FMB can directly detect let-7a in serum with high sensitivity and without any pre-treatment, and good recoveries were observed for let-7a in serum samples, demonstrating their potential application to the analysis of serum samples. The HCR-FMB exhibits several advantages, including rapidity, enzyme-free, miniaturization, ease-of-operation, field-deployment applicability, minimal-equipment, and cost-effectiveness. The HCR-FMB can be considered a revolutionary detection device that rapidly adapts and deploys in various settings, especially in low medical resource regions.