Hiroya Kirimura

Gold thin layer-assisted DNA immobilization for photoelectrochemical DNA sensor

Electrochemical biosensors have been developed due to its potential to be a compact medical diagnostic devise with high sensitivity. So far we have developed a photoelectrochemical DNA sensor using transparent semiconductor films such as tin-doped indium oxide (ITO), in which probe DNAs that captures fluorescence-labeled target DNAs were immobilized on semiconductor via silane coupling reagent such as aminopropyl triethoxy silane (APTES). Here we aimed to provide an effective DNA immobilization technique using gold thin layer in order to obtain higher photocurrents to noise ratio. Gold thin film (1nm thickness) deposited over semiconductor electrode serves as a substrate to immobilize a thiol-modified DNA (24bases) at its end that can capture fluorescence-labeled target DNA by hybridization. The sensitivity in this method was approximately 4times higher than that in APTES.