Electrochemically deposited Ag structure-based ECL sensing platform for KRAS gene detection in the tumor tissues

In this work, a novel electrochemiluminescence (ECL) biosensor was fabricated to detect the mutant KRAS gene in the tumor tissues. Firstly, a new kind of chitosan-based dots was prepared and regulated by phenylboronic acid (PBA) as ECL nanoprobe. Furthermore, the electrochemically deposited Ag structures with controllable morphology have been developed on the electrode. The detailed electrochemical deposition condition of Ag structure has been investigated deeply. Due to the synergistic effect of the large active surface area and the high conductivity , the layered Ag flower-like structure with branches can significantly enhance the ECL intensity of CS-PBA dots by 12.1 times. Finally, the toehold mediated strand displacement strategy was employed in the ECL biosensor to quantitatively detect mutant KRAS gene with the range of 0.01 pM to 10 nM. The limit of detection was 3.3 fM. This biosensor has been used successfully to analyze the target DNA in the tumor tissues of actual cancer patients . The results showed the novel sensing platform possessed great potential for clinical analysis.