Programmable nanoassembly consisting of two hairpin-DNAs for p53 gene determination.

As one of the most exciting building blocks, DNA has gained increasing attention in the construction of promising nanostructures for various biological and medical purposes. In this contribution, we have developed an easily constructed DNA nanoassembly-based biosensing system that consists of one signal hairpin probe (SHP) and one label-free hairpin probe (LHP) for target p53 gene analysis. The probes of SHP and LHP were designed to be incapable of interacting with each other in the absence of the p53 gene. When the target gene is introduced, the 3' end of SHP (or LHP) hybridizes with the middle region of LHP (or SHP), leading to polymerase-sustained DNA nanoassembly. Because one target species can exhaust many building scaffolds to execute the programmable nanoassembly in one-pot approach, the fluorescence intensity of SHP is greatly enhanced in the presence of target gene in a simple and robust manner. The practical applicability was successfully demonstrated by screening target gene extracted from cancer cells. We believe this intriguing sensing strategy and desirable assay ability would provide new opportunities to develop versatile biochemical analysis methods.