▎ 摘　　要

Numerous carbon-based biosensors issued mechanical exfoliation, epitaxial growth, reduced graphene oxide, and chemical vapor deposition have been investigated for highly sensitive and specific detection of DNA. As a promising route for designing electrochemical biosensor-based flexible substrates, the laser-induced graphene technique, which provides a cheap, technologically simple, and highly robust sensing platform, has been widely adopted. However, DNA-based biosensors' efficiency is strongly dependent on how DNA probes are tethered to the nanomaterials. In view of this, poly-cytosine (poly-C) DNA has shown outstanding adsorption to multiple inorganic nanomaterials, including gold (Au), zinc oxide (ZnO), tungsten disulfide (WS2), graphene oxide (GO), and graphene. In this work, a poly C(15)-tailed diblock DNA probe is used to anchor to carbonized working electrode issued laser-induced method. Meanwhile, the second block modified with ferrocene (Fc) derivatives is lifted at the surface for DNA sequence recognition. Following this strategy, the developed biosensor leads to a limit of detection (LOD) of 57 fM, which was superior or comparable to some previously reported methods. Moreover, the proposed electrochemical DNA biosensor exhibits high specificity in differentiating the comple-mentary DNA from non-complementary DNA (ncDNA), and mismatched DNAs (MM-DNA) sequences. Finally, the easily constructed laser-induced graphene electrode biosensor showed an ability to detect DNA in human serum as a complex environment, making our approach a promising avenue for disease diagnosis.