We have developed a point-of-care (POC) lateral flow biosensor (LFB) for universal protein detection based on a proximity hybridization-mediated protein-to-DNA signal transducer, isothermal exponential amplification (EXPAR) and catalytic hairpin assembly...

In this work, we demonstrated an ultrasensitive approach with a dual-amplification strategy for DNA assay based on isothermal exponential amplification (EXPAR) and the hybridization chain reaction (HCR). In the presence of target DNA, the hairpin probe DNA (HP1) recognized and partially hybridized with the target DNA to form double-stranded structures containing the full recognition sequences for nicking endonuclease and then initiated EXPAR. Under the reaction of EXPAR, a large number of single-stranded DNA (ssDNA) was produced in the circle of nicking, polymerization, and strand displacement. The resulting ssDNA can bind to the surface-bound probe on the well of the microplate and trigger the hybridization chain reaction, resulting in the production of numerous double-stranded DNA concatamers with biotin labeling. In the presence of streptavidin-conjugated horseradish peroxidase (HRP), the amplified signal can be detected by a spectrophotometer via HRP-catalyzed substrate 3,3′5,5′-tetramethylbenzidine (TMB). This proposed dualamplification method provides a detection limit of 74.48 aM, which also exhibits good linearity ranging from 0.1 fM to 100 pM.

No abstract

No abstract

No abstract