G-quadruplex-based DNAzyme for sensitive mercury detection with the naked eye

Mercury detection remains a critical challenge in environmental and health monitoring. Current methods often require complex instrumentation or reagents. Prior research has shown that mercury can interact with DNA structures, altering their enzymatic activity. However, the precise mechanism of this interaction is not fully understood. No prior work had resolved how mercury affects DNAzyme function in a way that could enable visual detection. This gap motivated the development of a new approach using DNA structures that change function in the presence of mercury. The TMB-H2O2 system is known for its colorimetric response to enzymatic activity. The need for a simple and selective detection method remains unmet. This paper addresses that need by exploring a DNA-based strategy.

The aim of this study was to investigate the effect of mercury ions on a specific DNAzyme structure. The researchers wanted to determine if mercury could inhibit the DNAzyme's activity in a measurable way. They focused on a T-containing G-quadruplex DNA, which is known for its peroxidase-like function. The motivation was to create a method that could detect mercury without specialized equipment. The study sought to test the DNAzyme's response in the TMB-H2O2 reaction system. The researchers also aimed to assess the selectivity and sensitivity of the method. A visual detection system would be a major advancement in field applications. This approach could provide a low-cost alternative to existing methods.

The study used a T-containing G-quadruplex DNA structure with peroxidase-like activity. The researchers tested the DNAzyme's function in the presence of mercury ions. They monitored the TMB-H2O2 reaction system to observe color changes. The inhibition of the DNAzyme by mercury was measured through this colorimetric response. The method relied on the formation of Hg(2+)-mediated T-T base pairs. The study compared the reaction in the presence and absence of mercury. The selectivity of the method was tested against other metal ions. The sensitivity was evaluated by measuring the lowest detectable mercury concentration.

Mercury ions were found to inhibit the peroxidase-like DNAzyme function of the T-containing G-quadruplex. This inhibition was mediated by Hg(2+)-mediated T-T base pairs. The TMB-H2O2 system showed a visible color change in response to this inhibition. The method demonstrated high selectivity for mercury over other metal ions. The sensitivity of the method was sufficient for low mercury concentrations. The visual detection was achieved without the need for instrumentation. The study confirmed the practicality of the method in real-world samples. The results suggest a promising approach for mercury monitoring.

The study concluded that mercury ions can inhibit the DNAzyme activity of a T-containing G-quadruplex. The inhibition was mediated by the formation of T-T base pairs. The TMB-H2O2 system provided a visual readout of this inhibition. The method showed high selectivity for mercury in the presence of other ions. The sensitivity of the method was sufficient for practical applications. The researchers propose that this approach could be used for field-based mercury detection. The visual nature of the method makes it suitable for low-resource settings. The findings suggest a new strategy for mercury monitoring that is both simple and effective.