Novel Electrochemical Biosensors For NADH Detection

Previous study has confirmed,NADH,as an important coenzyme for all biological metabolic processes,is related to a variety of diseases including cancers,Parkinson's disease.Therefore,to detect cellular NADH level can provide a new way for the early diagnosis and detection of related diseases.Compared with conventional detection methods,in this paper,we take advantage of NADH redox properties,through the new composite electrode structure,by using classical "three-electrode" configuration to detect NADH.To achieve low detection limit of NADH,inspired by the DNA origami,we constructed an amino-graphene/DNA tetrahedron/gold nanoparticle modified gold disk electrode,which was confirmed by AFM imaging for the successful construction.The novel sensor can successfully reduce NADH oxidation voltage to 0.3V with great selectivity and regeneration.Also,the proposed biosensor presented a stable linear detection range of NADH from 1 fM to 10 pM.In order to explore cheap and easy fabricated biosensor for NADH detection,taking advantage of the biocompatibility of 316 L stainless steel,we constructed an amino-graphene coated stainless steel fiber felt electrode,which was characterized by SEM and XPS.The NADH apparent oxidation voltage was reduced to-0.2 V through the proposed biosensor,with a stable linear detection range of NADH from 1 ?M to 100 ?M.Both the regeneration and selectivity of composite film-modified electrode are investigated and proved to be robust.