CRISPR/Cas12a-Loaded intelligent DNA hydrogel for Universal and Ultrasensitive Exosome Assay

Abstract

Tumor-derived exosomes are crucial for early non-invasive and accurate tumor diagnosis in clinical. The development of highly sensitive, simple and intuitive exosome assays has sparked a research upsurge in clinical diagnostics. Here, we develop a bio-responsive the 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 of the intelligent DNA hydrogel network. The target competitively disintegrates the region of the DNA linkers then Cas12a/crRNA encapsulated in the intelligent DNA hydrogel can be released and activated by the collateral sequence, resulting in a high fluorescent intensity for exosome detection at the detection limit of 119 particles/μL. Moreover, a prefabricated 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 LOD 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. Collectively, this study constructs an ultra-sensitive detection platform for exosomes, which enables one-step sensing and dual signal output, making it a promising tool for the application of liquid biopsy based on exosomes in clinical diagnosis.