Hybridization Chain Reaction-Based Label-Free Colorimetric Sensor for Detection of Cancer Marker p53 Gene

Abstract

The p53 gene is an important tumour suppressor gene, which has an important impact on the early diagnosis of cancer. Here, inspired by the fact that single-stranded DNA (ss-DNA) can be nonspecifically adsorbed on the surface of nanogold, we report on a sensitive and cost-effective new method to detect the p53 gene by combining hybridization chain reaction (HCR) with gold nanoparticles. The long double helix structure generated by HCR could not be adsorbed on the nanogold surface after the addition of the p53 gene. When an appropriate amount of Na⁺ is introduced into the solution, the nanogold aggregates and the color of the solution changes from red to blueviolet. The sensor has a high sensitivity with a detection limit of 2 nM visible to the naked eye and a quantitative detection limit of 0.2 nM using a UV-visible spectrophotometer. Notably, by combining fluorescence spectroscopy and gel electrophoresis, the science and specificity of p53 gene-induced HCR is systematically validated. The use of an enzyme-free, label-free colorimetric method to detect the p53 gene greatly reduces the complexity and cost of the experiment. This study has a broad market application prospect and provides a new method for early mass screening of cancer genes.