A highly sensitive fluorescent aptasensor for detection of prostate specific antigen based on the integration of a DNA structure and CRISPR-Cas12a

Herein, a facile fluorescent CRISPR-Cas12a-based sensing strategy is presented for prostate specific antigen (PSA), as a prostate cancer biomarker, with the assistance of a cruciform DNA nanostructure and PicoGreen (PG) as a fluorochrome. Highly sensitive recognition of PSA is one of the virtues of the proposed method which comes from the use of unique features of both CRISPR-Cas12a and DNA structure in the design of the aptasensor. The presence of PSA creates a cruciform DNA nanostructure in the sample which can be loaded by PG and make sharp fluorescence emission. While, when there is no PSA, the CRISPR-Cas12a digests sequences 1 and 3 as single-stranded DNAs, causing no DNA structure and a negligible fluorescence is detected after addition of PG. This aptasensor presents a sensitive recognition performance with detection limit of 4 pg/mL and a practical use for determination of PSA in serum samples. So, this analytical strategy introduces a convenient and highly sensitive approach for detection of disease biomarkers.