CRISPR/Cas12a-Sheared ZIF-Based Heterojunction to Allow Polarity-Switchable Photoelectrochemical and Nanozyme-Enabled Colorimetric Dual-Modal Biosensing
Shuyun Meng, Yuye Li, Na Dong, Shuda Liu, Qingfa Gong, Yifan Liu, Li Zhang, Qijian Niu, Dong Liu, Tianyan You
Abstract
Modulating the migration of interfacial carriers in heterojunctions is critical for driving the signal response of high-performance optical biosensors. In this study, a polarity-switchable photoelectrochemical (PEC) and nanozyme-enabled colorimetric dual-modal biosensor is designed to modulate the interfacial carrier migration of the zeolitic imidazolate framework (ZIF)-based heterojunction by exploiting stem-loop DNA and the CRISPR/Cas12a system. Specifically, ZIF-hemin (ZIF-Hemin) is assembled at the CdSe/NH 2 -rGO interface via stem-loop DNA to form a ZIF-based heterojunction. Stem-loop DNA with a reinforcing rib effect enhances binding and accelerates the interfacial carrier migration of the heterojunction. In the presence of the target Cry1Ab, the CRISPR/Cas12a system is activated to shear the ZIF-based heterojunction, resulting in the disintegration of the heterojunction and the disappearance of interfacial carrier migration. At this point, ZIF-Hemin is released from the CdSe/NH 2 -rGO interface, with the photocurrent switching from the anode to the cathode. Meanwhile, due to its rich accessible active sites, the released ZIF-Hemin nanosheet shows high peroxidase-like catalytic activity and generates colorimetric signals. The dual-modal biosensor demonstrates excellent performance in selectivity and sensitivity, with low detection limits of 0.05 pg mL –1 (PEC) and 0.4 pg mL –1 (colorimetric). This work provides a general strategy to improve the performance of optical biosensors by modulating the migration of interfacial carriers in heterojunctions.