pH‐Driven Precise Control of Hybridization Reaction Kinetics for Rapid DNA Assay

The development of DNA assays based on gold nanoparticles (AuNPs) holds great promise for point‐of‐care diagnosis at molecular level; nevertheless, how to accelerate the hybridization reaction rates, and design rapid DNA assay in aqueous solution remains challenging. Herein, a pH switchable AuNP aggregation system, functionalized with compound Y1, was set up. This method provided an elegant strategy for the precise control of DNA hybridization reaction kinetics when Y1 was co‐functionalized with ssDNA on the AuNPs. Using this strategy, real‐time DNA detection was realized by simply adjusting the pH value of the solution without affecting the sensitivity. Particularly worth mentioning, this system maintained high specificity, and were capable of accurately discriminating against single‐based mismatched sequences. In total, this system significantly improved the rapidity and robustness of ssDNA modified AuNPs, providing sound basis for the low‐cost, and disposable molecular diagnosis design. We demonstrated that Y1 modified AuNP triggered pH reversible aggregation behaviour in aqueous solution because of the varied hydrogen bonding strength derived from carboxylic acid. In this study, Y1‐ssDNA co‐functionalized AuNP, instead of ssDNA modified AuNP, was selected for DNA detection. Using this system, the target DNA the detection time can be shortened to within 1 min by simply adjusting the solution pH.