Metal Organic Framework-Based Bio-Barcode CRISPR/Cas12a Assay for Ultrasensitive Detection of MicroRNAs

CRISPR/Cas12a has shown great potential in molecular diagnostics, but its application in sensing of microRNAs (miRNAs) was limited by sensitivity and complexity. Here, we have sensitively and conveniently detected microRNAs by reasonably integrating metal-organic frameworks (MOFs) based biobarcodes with CRISPR/Cas12a assay (designated as MBCA). In this work, DNA-functionalized Zr-MOFs were designed as the converter to convert and amplify each miRNA target into activators that can initiate the trans-cleavage activity of CRISPR/Cas12a to further amplify the signal. Such integration provides a universal strategy for sensitive detection of miRNAs. By tuning the complementary sequences modified on nanoprobes, this assay achieves subattomolar sensitivity for different miRNAs and was selective to single-based mismatches. With the proposed method, the expression of miR-21 in different cancer cells can be assessed, and breast cancer patients and healthy individuals can be differentiated by analyzing the target miRNAs extracted from serum samples, holding great potential in clinical diagnosis.