CRISPR/Cas12a-loaded intelligent DNA hydrogel for universal and ultrasensitive exosome assay

Tumor-derived exosomes are crucial for early non-invasive and accurate tumor diagnosis in clinical diagnostics. The development of highly sensitive, simple, and intuitive exosome assays has sparked a research upsurge in clinical diagnostics. Here, we develop a bio-responsive intelligent DNA hydrogel loaded with CRISPR/Cas12a for universal and ultrasensitive detection of the exosomes. The aptamer serves as the target response unit and switch, competitively disintegrating the region of the DNA linkers and then Cas12a/crRNA was released and activated, resulting in a high fluorescent intensity for exosome detection at the detection limit of 119 particles/μL. Moreover, a constructed colorimetric tube is made by loading a colorimetric filter membrane on the tube lid and intelligent DNA hydrogel on the tube bottom, which enables one-pot portable colorimetric detection. Without the need for laboratory instruments and professionals, this strategy allows for naked eye detection with limit of detection as low as 10⁴ particles/μL, and shows great applicability in distinguishing between healthy individuals, pretreatment patients, and post-treatment patients after obtaining a testable analyte. In this study, an ultrasensitive detection platform for exosomes that enables one-step sensing and dual signal output was introduced. The findings here suggest that this platform is a promising tool for the application of liquid biopsy based on exosomes in clinical diagnosis.