CRISPR-powered microfluidic biosensor for preamplification-free detection of ochratoxin A

The CRISPR technology, which does not require complex instruments, expensive reagents or professional operators, has attracted a lot of attention. When utilizing the CRISPR-Cas system for detection, the pre-amplification step is often necessary to enhance sensitivity. However, this approach tends to introduce complexity and prolong the time required. To address this issue, we employed Pd@PCN-222 nanozyme to label single-stranded DNA, referred to as Pd@PCN-222 CRISPR nanozyme, which serves as the reporter of the CRISPR system. Pd@PCN-222 nanozyme possess exceptional catalytic activity for the reduction of H2O2. Compared with traditional electrochemical probe ferrocene and methylene blue without catalytic activity, there is a significant amplification of the electrochemical signal. So the need for pre-amplification was eliminated. In this study, we constructed a CRISPR-Cas system for ochratoxin A, utilizing the Pd@PCN-222 CRISPR nanozyme to amplified signal avoiding pre-amplification with outstanding detection of 1.21 pg/mL. Furthermore, we developed a microfluidic electrochemical chip for the on-site detection of ochratoxin A. This achievement holds significant promise in establishing a practical on-site detection platform for identifying food safety hazards. Schematic illustration of the electrochemical biosensor based on CRISPR-Cas12a integrated Pd@PCN-222 for OTA detection. [Display omitted] •The enzyme formed by the combination of Pd@PCN-222 and CRISPR successfully avoids the pre-amplification step and reduces experimental time.•Combined with the OTA aptamer, a CRISPR-Cas system for detecting OTA was constructed with a detection range of 0.005-50ng/mL and a minimum detection limit of 1.21pg/mL.