Construction And Response Performance Research Of Gold Nanoparticles/Graphene Molecular Sensing Electrode Device

Depression is one of the most common mental disorders in modern society,its incidence is related to psychological,biological and social environment and other factors,among which biological factors are manifested as abnormal levels of biological small molecules in the human body,such as neurotransmitters,neurotransmitter hormones,amino acids and so on.Simple and highly effective detection of these substances for the research,diagnosis and treatment of depression is of great significance.However,there are few electrochemical sensing devices used to detect these biomolecules,and it is difficult to detect them simultaneously because of the similar oxidation potential of these substances.Graphene has been widely studied in the field of electrochemical sensing because of its excellent electrochemical properties and good synergistic effect when combined with noble metal nanoparticles.Based on this,the gold nanoparticles/graphene molecular sensor electrode device(MSED)will be constructed by using the gold nanoparticles/graphene molecular sensor electrode integrated flow cell to detect depression-related biological small molecules.The research content of this paper can be divided into the following three parts:(1)Gold nanoparticles/graphene molecular sensing electrode was prepared by electrochemical process using in situ modification on the surface of different region of graphene-based standard electrode,using Au NPs@Gr as the working electrode,platinum(Pt)as the counter electrode and silver/silver chloride(Ag/Ag Cl)as the reference electrode.The flow cell was fabricated by photocuring 3D printing.The gold nanoparticles/graphene molecular sensor electrode device(MSED)was constructed by integrating the prepared sensor electrode with the flow cell.(2)The electrochemical response of the MSED to dopamine(DA),5-hydroxytryptamine(5-HT)and melatonin(MEL)was studied.The results showed that the MSED can achieve selective detection of DA,5-HT and MEL,and showed good sensing performance.The concentrations of DA,5-HT and MEL were linear in the range of 0.1-70 μM,0.1-100 μM and0.1-150 μM,respectively.The detection limits were 0.054 μM,0.071 μM and 0.087 μM(S/N= 3),respectively.In addition,the repeatability,reproducibility,stability and anti-interference of the sensor electrode device were studied in detail,and the practical value of the sensor electrode device was verified.(3)The electrochemical detection performance of the MSED for two essential amino acids,TRP and MET,was further studied.The results showed that the MSED has good electrocatalytic performance for TRP and MET.When TRP and MET coexist,the detection linear range were0.1 ～ 200 μM and 10 ～ 1000 μM,respectively,and the detection limits were 0.067 μM and 6.5μM(S/N = 3),respectively.The MSED had good reliability and anti-interference ability in the detection of TRP and MET,and is expected to be widely used in the detection of more small biological molecules.