A Facile, Label-free and Versatile Fluorescence Sensing Nanoplatform Based on Titanium Carbide Nanosheets for the...

The construction of a universal nanoplatform for sensitive detection of multiple targets of interest is of great importance in different research fields. Herein, by ingeniously integrating the target recognition sequences and G-rich sequences into a single-stranded multifunctional DNA probe and adopting Ti₃C₂ nanosheets as an efficient fluorescence quencher, a simple, low-cost and easy operation fluorescence sensing nanoplatform was proposed. Without an analytical target, the hydrogen bond and metal chelate interaction between the target recognition region of the DNA probe and Ti₃C₂ nanosheet induce the selective self-assembly of highly fluorescent thioflavin T (ThT)-intercalated DNA probe onto the surface of Ti₃C₂ nanosheets, resulting in dramatic decrease of fluorescence emitted by ThT-G-quadruplex. In the presence of a target, the target recognition region will selectively bind with the target and the constrained DNA probe is released from the Ti₃C₂ nanosheets surface, leading to enhanced fluorescence recovery of ThT-G-quadruplex. As a proof of concept, the sensitive and selective detection of p53 gene, Hg²⁺, and adenosine with the assistance of Ti₃C₂ nanosheets-based fluorescence sensing nanoplatform were successfully realized. Moreover, it is also applicable for the evaluation the level of these analytical targets in real samples. By simply switching the recognition sequences of DNA probe, the universal sensing strategy could also be applied for detecting many other types of targets. The simple and universal sensing nanoplatform is expected to promote wide applications in environment monitoring and bioanalysis.