Chemical Cyclic Amplification: Hydroxylamine Boosts the Fenton Reaction for Versatile and Scalable Biosensing

Nucleic acid detection is undoubtedly one of the most important research fields to meet the medical needs of genetic disease diagnosis, cancer treatment, and infectious disease prevention. However, the practical detection methods based on biological amplification are complex and time-consuming and require highly trained operators. Herein, we report a simple, rapid, and sensitive method for the nucleic acid assay by fluorescence or naked eye using chemical cyclic amplification. The addition of hydroxylamine (HA) during the Fenton reaction can continuously generate hydroxyl radicals (center dot OH) via Fe3+/Fe2+ cycle, termed as hydroxylamine boosts the Fenton reaction (Fenton-HA system). Meanwhile, the reducing substances, such as terephthalic acid or o- phenylenediamine, react with center dot OH to generate oxidized substances that can be recognized by the naked eye or detected by fluorescence so as to realize the detection of Fe3+. The concentration of Fe3+ has a good linear relationship with fluorescence intensity in the range of 0.1 to 100 nM, and the limit of detection is calculated to be 0.03 nM (S/N = 3). Subsequently, Fe was introduced into the nucleic acid hybridization system after the Fe source was transformed into Fe3+, and the nucleic acids were indirectly determined by this method. This Fenton-HA system was used for sensing HIV-DNA and miRNA-21 to verify the validity of this method in nucleic acid detection. The detection limits were as low as 2.5 pM for HIV-DNA and 3 pM for miRNA-21. We believe that our work has unlocked an efficient signal amplification strategy, which is expected to develop a new generation of highly sensitive chemical biosensors.

Automated summary

Nucleic acid detection is crucial for genetic disease diagnosis, cancer treatment, and infectious disease prevention. However, current methods based on biological amplification are complex and time-consuming. In this study, a simple and rapid nucleic acid assay using chemical cyclic amplification was developed. The Fenton-HA system, which continuously generates hydroxyl radicals via Fe3+/Fe2+ cycle, was introduced for the detection of Fe3+. The method showed good sensitivity and could be used for the detection of HIV-DNA and miRNA-21 with low limits of detection.