Colorimetric and photothermal dual-modal analysis of a cancer-related gene based on G-quadruplex-hemin cascade signal amplification

p53 gene is one of the most important anticancer genes and has been recognized as a typical biomarker for the early diagnosis of cancers. In this paper, a portable point-of-care testing (POCT) platform was developed for the colorimetric and photothermal dual-modal analysis of the p53 gene. Long concatemer G4 structures with high catalytic activity were formed by a target-driven hybridization chain reaction, and their catalytic properties can further be enhanced with the help of iodide ions. This dual-modal method realized the sensitive multicolor visual point-of-care detection of the p53 gene, where color variations from colourless to blue were easily distinguished by the naked eye. The temperature output was achieved by effective photothermal conversion and regulation guided by the accumulated concatemer G4 complexes in the TMB–H2O2 system, avoiding the need for complex instruments. The proposed dual-modal assay for p53 gene detection is cost-effective, simple, highly sensitive (3.34 pM), stable, and remarkably selective. It was also applied to determine the concentration of the p53 gene in spiked serum samples.