Recent progress in aptamer and CRISPR-Cas12a based systems for non-nucleic target detection

Efficient and sensitive detection of targets is one of the motivations for constant development and innovation of various biosensors. CRISPR-Cas12a, a new generation of gene editing tools, has shown excellent application potential in biosensor design and construction. By combining with the specific recognition element-aptamer, a single-stranded oligonucleotide obtained by systematic evolution of ligands by exponential enrichment (SELEX) in vitro screening, CRISPR-Cas12a also shows superior performance non-nucleic acid targets detection, such as small molecules, proteins, virus and pathogenic bacteria. However, aptamer and CRISPR-Cas12a (CRISPR-Cas12a/Apt) still face some problems in non-nucleic acid target detection, such as single signal response mode and narrow linear range. The development of diverse CRISPR-Cas12a/Apt biosensors is necessary to meet the needs of various detection environments. In this review, the working principle of CRISPR-Cas12a/Apt was introduced and recent progress in CRISPR-Cas12a/Apt in the application of non-nucleic acid target detection was summarized. Moreover, the requirements of critical parameters such as crRNA sequence, activator sequence, and reaction system in the design of CRISPR-Cas12a/Apt biosensors were discussed, which could provide the reference for the design of efficient and sensitive novel non-nucleic acid target biosensors. In addition, the challenges and prospects of CRISPR-Cas12a/Apt-based biosensor were further presented.