Polyvalent Aptamers Structure-Mediated Fluorescent Aptasensor for the Early Diagnosis of Alzheimer's Disease by Coupling with HCR and CRISPR-Cas System.

The early diagnosis of Alzheimer's disease (AD) plays a vital role in slowing the progression of AD and improving the quality of human life. However, it is still a challenge in the medical field. Herein, an ultrasensitive fluorescent aptasensor was designed for the detection of special phosphorylated tau181 (P-tau181) by coupling with polyvalent aptamers (PAs) structure, hybridization chain reaction (HCR), and the CRISPR-Cas system. Coupling with the signal amplification strategy, the specific recognition ability of the aptamer, and the high cleavage activity of Cas12a protein, the designed aptasensor showed a wide linear range (0.1-10 pg/mL), a low detection limit (0.069 pg/mL), high selectivity, and excellent anti-interference ability for the detection of P-tau181. Moreover, the aptasensor can efficiently analyze P-tau181 in artificial cerebro spinal fluid (aCSF) and serum, proving that it has a promising application in the early diagnosis of AD.