A sensitive detection of C-reactive protein based on the combination of CRISPR/Cas13a, MNPs and RNase H.

C-reactive protein (CRP) is a potential risk factor for disease. Here, developed a rapid and accurate fluorescence biosensor for detecting CRP, which contributes to early diagnosis and timely treatment of diseases. The CRP binds with the aptamer resulting in the probe 1 (P1) releasing from the complex of aptamer/P1/magnetic nanoparticles (MNPs). After magnetic separation, the free P1 hybridized with the RNA (P2) modified on the MNPs, leading to the P2 being multiple-turnover cut by ribonuclease H (RNase H). The formed free RNA can specifically bind with the crRNA and the tans-cleavage activity of CRISPR/Cas13a was triggered, leading to the RNA reporter containing a dye and quencher pair being cleaved and generating the fluorescence signal. This developed fluorescent biosensor takes full advantage of the synergy of aptamer, RNase H, MNPs and CRISPR/Cas13a. Here, the developed fluorescent biosensor exhibits excellent sensitivity and specificity towards the detection of CRP with a linear range from 10 pg/mL to 200 ng/mL. The detection limit is low down to 7.5 pg/mL. Additionally, this method successfully detected the CRP in human serum samples with satisfactory recoveries. Therefore, this developed biosensor will offer a valuable tool for the rapid diagnosis of CRP-related diseases.