Applications of Catalytic Hairpin Assembly Reaction in Biosensing

Abstract

Nucleic acids are considered as perfect programmable materials for cascade signal amplification and not merely as genetic information carriers. Among them, catalytic hairpin assembly (CHA), an enzyme‐free, high‐efficiency, and isothermal amplification method, is a typical example. A typical CHA reaction is initiated by single‐stranded analytes, and substrate hairpins are successively opened, resulting in thermodynamically stable duplexes. CHA circuits, which were first proposed in 2008, present dozens of systems today. Through in‐depth research on mechanisms, the CHA circuits have been continuously enriched with diverse reaction systems and improved analytical performance. After a short time, the CHA reaction can realize exponential amplification under isothermal conditions. Under certain conditions, the CHA reaction can even achieve 600 000‐fold signal amplification. Owing to its promising versatility, CHA is able to be applied for analysis of various markers in vitro and in living cells. Also, CHA is integrated with nanomaterials and other molecular biotechnologies to produce diverse readouts. Herein, the varied CHA mechanisms, hairpin designs, and reaction conditions are introduced in detail. Additionally, biosensors based on CHA are presented. Finally, challenges and the outlook of CHA development are considered.

Rapid point-of-care testing for SARS-CoV-2 virus nucleic acid detection by an isothermal and nonenzymatic Signal amplification system coupled with a lateral flow immunoassay strip

“…2 A). However, the probes are opened by the target RNA, which acts as a toehold switch, yielding a stable hybrid duplex through a free-energy-driven, isothermal, autonomous process [ 19 , 26 ]. In this reaction, the target RNA sequence plays the role of the enzyme that would be required to catalyze H1-H2 hybridization, without being consumed in the process.…”

Programming Cell-Free Biosensors with DNA Strand Displacement Circuits

“…We believe that this platform opens the door to enabling other types of molecular computation in cell-free systems. For example, an amplification circuit such as a catalytic hairpin assembly [54] could be applied to ROSALIND with TMSD for amplifying signals and making a sensor ultrasensitive. Beyond thresholding, other operations demonstrated in DNA seesaw gate architectures could be ported to this platform for various computations [26].…”

Recent advances in aptamer applications for analytical biochemistry

“…According to Peng et al [ 39 ], abnormal concentrations of ATP are associated with many diseases and cancers, and quantitative detection of ATP is thus of great importance for disease diagnosis and prognosis. These researchers developed a new dual recycling amplification sensor integrated with catalytic hairpin assembly (CHA) [ 40 ] to achieve high sensitivity for fluorescent detection of ATP. The association of the target ATP with the aptamer beacons causes the allosteric structure switching of the aptamer beacons to expose the “toehold” regions, which hybridize with and unfold the fluorescently quenched hairpin signal probes (HP1) to recycle the target ATP and to trigger CHA between HP1 and the secondary hairpin probes (HP2) to form HP1/HP2 duplexes.…”