Breaking barriers: Overcoming low abundance of miR-122 with E-DDM for precise detection in HCC patients

Rapid and accurate detection of miR-122 levels is beneficial for better monitoring the occurrence and progression of Hepatocellular Carcinoma. The negative correlation between miR-122 and HCC implies that there is an extremely low abundance of miR-122 in the peripheral blood of HCC patients, which makes precise detection of miR-122 particularly challenging. Herein, based on our understanding of DNA molecular mechanisms, we have developed an extended-based dual-driven DNA molecular machine (E-DDM) for highly sensitive detection of miR-122. The uniqueness of E-DDM lies in the introduction of additional extension probes, which allows for the immediate activation of fluorescence signals when the target is present, resulting in faster detection speed and reducing the time consumption by 30%. Additionally, with the combination of a 1st drive composed of polymerase/nickase and a 2st drive composed of palindrome sequence/polymerase, E-DDM can easily achieve ultrasensitive and precise detection of miR-122. Overall, the design of extended significantly improves the detection efficiency of E-DDM and the synergistic effect of dual-drive ensures the sensitivity of E-DDM detection. As a validation of the innovative concept, we have achieved quantitative analysis of miR-122 in clinical samples using E-DDM, with a detection sensitivity of 0.82 fM. This detection method has been successfully developed to provide new insights in RNA biosensing and biomedical diagnostics.