An integrated magnetic-microfluidic chemiluminescence platform for rapid quantification of exosomal miR-21 associated with breast cancer.

Accurate quantification of microRNAs (miRNAs) is crucial for early cancer diagnosis, but conventional techniques, such as quantitative PCR and microarrays, are time-consuming, costly, and require complex instrumentation. In this study, we developed an integrated magnetic-microfluidic chemiluminescence (CL) platform for the rapid and sensitive detection of miR-21, a key biomarker associated with breast cancer. The platform integrates the magnetic nanoparticle-based capture of the target miRNA, performing sandwich hybridization and enzyme-driven chemiluminescence directly on the chip. This design enables efficient magnetic separation and produces a clean, low-background signal within the compact microchannel network. Using only 10 µL of sample, the assay delivers a quantitative chemiluminescent signal readout within 15 minutes and achieves a limit of detection of 0.3 pM with a linear dynamic range from 0.3 to 1000 pM ( = 0.98). Validation with exosomal RNA isolated from MCF-7 breast cancer cells confirmed the analytical feasibility of the platform. The proposed platform offers high sensitivity, rapid analysis, and compatibility with clinical exosome samples. Importantly, the integrated microfluidic system operates in a power-free manner, driven solely by capillary action and magnetic manipulation, making it suitable for point-of-care applications.