Active CRISPR-Cas12a on Hydrophilic Metal–Organic Frameworks: A Nanobiocomposite with High Stability and Activity for Nucleic Acid Detection

Abstract

CRISPR-Cas12a is an accurate and responsive biosensing technique, but its limited stability has restricted its widespread applications. To address this, we propose a strategy using metal−organic frameworks (MOFs) to protect Cas12a from harsh environments. After screening multiple candidate MOFs, it was found that hydrophilic MAF-7 is highly compatible with Cas12a, and the as-formed Cas12a-on-MAF-7 (COM) not only retains high enzymatic activity but also possesses excellent tolerance to heat, salt, and organic solvents. Further investigation showed that COM can serve as an analytical component for nucleic acid detection, resulting in an ultrasensitive assay for SARS-CoV-2 RNA detection with a detection limit of 1 copy. This is the first successful attempt to create an active Cas12a nanobiocomposite that functions as a biosensor without the need for shell deconstruction or enzyme release.

DNA Robots for CRISPR/Cas12a Activity Management and Universal Platforms for Biosensing

“…The trans -cleavage of Cas12a is multiple turnover, thereby enabling the continuous cleavage of the ssDNA substrate to achieve signal amplification . These unique activities make the Cas12a system a good signal transduction element that can perform both biometric events and signal conversion output, and amplify the output signal to facilitate sensitive detection . Based on this, precisely and controllably managing the cleavage behavior of the CRISPR/Cas12a system has become a key component in developing excellent biosensing methods.…”

Fluorescent MOF and Its Gel Composite for the Fluorescence Recovery “Turn-On” Detection of Al3+ Ions and “Turn-Off” Detection of Oxo-Anions

“…In addition, the working process of the sensor is easy with a colorimetric response, and the sensor is portable. In this regard, compared to diverse fluorescence materials, − the coordination polymers (CPs) or metal–organic frameworks (MOFs) show its meritocracy toward the detection of numerous analytes. − MOFs have interesting structural features such as structural variety, host–guest complexation ability, , purposefully rooted reactive sites, , and ability to display structure–property relationship. − These important features render to perform as an effective sensory material. − Furthermore, the atomistically assigned functionalities assist in establishing of the sensing mechanism. Clearly the single crystallography , particularly, the single crystal to single crystal transformation is a brilliant technique to investigate the mechanism, but sometimes it is very challenging to get a single crystal structure of the sensor after analyte recognition. − It has been observed that by tuning the MOF network with Lewis basic or uncoordinated functionality, the sensitivity of the probe can be significantly improved. , Importantly, for multisensory materials, it is expected that the sensor should have the ability to rationalize diverse signal transduction.…”