CRISPR-Cas12a powered multifunctional DNA nanodumbbell lock biosensor for multiple molecular detection

Detection of multiple biomarkers for accurate diagnosis of disease is highly desirable but remains challenging. Here, we developed a versatile diagnostic biosensor (SMARTLOCK) through the unique combination of DNA tetrahedron, nonlinear HCR and CRISPR-Cas12a system for simultaneous detection of multiple nucleic acids, small molecules, proteins and different types of combinations. Two DNA tetrahedrons are assembled into a functional dumbbell lock, which was unlocked by the target molecules, thereby triggering a two-stage signal amplification of nonlinear HCR and CRISPR-Cas12a to generate powerful fluorescence signals. The capability of multi-target simultaneous detection of SMARTLOCK is demonstrated in the detection of miR-141, miR-375, miR-21, ATP, cortisol, insulin and their combinations. SMARTLOCK could selectively (specificity = 93.3%) and sensitively (sensitivity = 90%) distinguish early-stage prostate cancer (PCa) patients (n = 10) from healthy donors (n = 30). Measurement of two PCa-related RNAs (miR-141 and miR-375) shows the potential of SMARTLOCK to be a highly accurate and low-cost tool for the screening, diagnosis and prognosis of various diseases.