Construction of a sandwich-type DNA biosensor based on functionalized MOF@COF nanomaterials for the detection of NSCLC biomarker ctDNA

MOF core, additional mesoporous diffusion channels were introduced between the MOF crystals, which can further increase the electron transfer rate of the electroactive substance MB. Secondly, the modification of AuNPs not only accelerates the electron transfer rate of the MOF@COF at the glassy carbon electrode (GCE) but also immobilizes large amounts of signal probes (SPs) and electroactive substances through the gold-nitrogen (Au-N) bond. The experimental results showed that the sensor exhibited a wide linear range from 1 fM to 100 nM, and the detection limit was as low as 0.31 fM. The results of clinical samples demonstrated that the method was effective in differentiating ctDNA levels between NSCLC patients and healthy populations. The electrochemical biosensor constructed using this strategy provides a potential analytical tool for early-stage clinical diagnosis of NSCLC.