A DNA biosensor integrating surface hybridization, thermo-responsive coating, laminar-flow technology and localized photothermal effect for efficient electrochemical detection of nucleic acids†

A hybrid electrochemical DNA biosensor that integrates various technologies, such as laminar flow, surface hybridization, DNA-microarray, thermo-responsive nanocoating and localized photothermal heating, is presented here. A photothermal module based on gold nanostructures photoactivated by a green-light source (532 nm) was developed for easy temperature management. The hybridization product is electrochemically detected by a three-planar-microelectrode system upon dsDNA denaturation. Performances of the hybrid biosensor were investigated by detection of the cDNA target, resulting in a sensitivity of about 2.62 μA nM⁻¹ cm⁻² and a limit of detection of 1.5 nM, as a function of the capture probe sequence. The findings facilitate the integration of multiple technologies, enabling the development of low-cost and point-of-care detection systems for molecular analysis.