Catalytic hairpin self-assembly for biosensing: Classification, influencing factors, and applications

As an enzyme-free signal amplification strategy, catalytic hairpin assembly (CHA) presents the advantages of flexible design and high efficiency. Combined with various signal output modes, CHA can be used for the biosensing of multiple analytes. With the in-depth study of CHA mechanism, some novel and excellent CHA strategies are put forward. In this paper, the classification, influencing factors and application of CHA in biosensing are introduced systematically. Firstly, different CHAs, including separate CHA, CHA combined with nanomaterials and CHA combined with other amplifications are discussed. Secondly, CHA influencing factors such as initiator, hairpin chain and experimental conditions are provided. After that, the biosensors combining CHA and fluorescent, colorimetric and electrochemical detection methods are summarized. Finally, some views on the challenges and prospects of CHA in the field of biosensing are highlighted. We believe this paper will provide useful guidance for the future development of nucleic acid amplification technology, nanotechnology and biosensing.