Application of nucleic acid signal amplification in biosensing and bioimaging

Nucleic acid amplification techniques are broadly employed in nucleic acid testing due to their efficient accumulation of nucleic acid sequences. With the development of biotechnology, they are further applied to proteins, living cells, extracellular vesicles (EVs) and even small molecule detection to amplify detection signals for ultra-sensitive bioanalysis. As important amplification techniques, isothermal amplification techniques, CRISPR/Cas system, DNA Walker and DNAzymes are playing an increasingly important role in signal magnification. Cooperating with functional nanomaterials, they present a wide availability in biosensing and bioimaging. This review gives a comprehensive summary of the four main signal amplification techniques mentioned above and their applications in biosensing and bioimaging. Finally, some of the challenges and further opportunities of nucleic acid amplification strategy in the current biomedical technology field are discussed.