Study On Biosensors Based On Bouquet-like Graphene/Ta Electrode

Graphene was a two-dimensional crystalline structure of single atomic layer.Compared with conventional one-dimensional(1D)nanomaterials,grapheme not only has a high surface area,but also possesses superior electron mobility and bio-compatibility.Moreover,CVD graphene electrodes has some advantages such as higher conductivity,fewer defects,stronger stability and longer life than other methods.And these characteristics were essential for the application of electrochemical biosensor.The bouquet-like graphene electrodes were prepared using the CVD method in this paper,such three-dimensional(3-D)graphene-sensing electrodes exhibited good electrocatalytic activity.Standing graphene nanosheets have rich catalytic sites.These catalytic sites prompt the adsorption and resolution for small molecules and the strong electron transport capability of the CVD graphene,which effectively improved the electrical signals for response to small molecule.The proposed bouquet-like grapheme electrodes in the application of electrochemical biosensors includes the following two aspects:(1)CVD graphene as an electrochemical sensing electrode for simultaneous detection of ascorbic acid(AA),dopamine(DA),uric acid(UA),tryptophan(Trp),and nitrite(NO2-)in human serum.Graphene/Ta electrodes provided a highly sensitive and selective option,with detection limits of AA,DA,UA,Trp,and NO2-of 1.58,0.06,0.09,0.10,and 6.45 ?M(S/N=3),respectively.This finding strongly indicates that the CVD graphene electrode can be applied as a high sensitive biosensor to detect five analytes in human serum.(2)Detection of biomolecules and DNA bases based on bouquet-like graphene nanosheets.A vertical graphene electrode was fabricated under optimized preparation conditions,and conjugated deoxyribonucleic acid(DNA)bases such as guanine(G),and adenine(A),dopamine(DA),and uric acid(UA)were chosen as models to provide a promising strategy for simultaneous detection of DA,UA,G,and A in biological samples.The proposed graphene electrode is a promising candidate in electrochemical sensing applications.The innovative points of this paper:(1)There have been no reports that graphene/Ta wire as a biosensor was used to detect AA,DA,UA,Trp,and NO2-.(2)Graphene film was grown several times on graphene substrate by Direct current(DC)arc plasma jet chemical vapor deposition(CVD)to fabricate bouquet-like graphene electrodes for the simultaneous detection of conjugated deoxyribonucleic acid(DNA)bases such as guanine(G)and adenine(A),dopamine(DA),and uric acid(UA),has not been reported.