Study On Drug Inhibition Evaluation Based On Electrochemical Enzyme Sensor Of Carbon Nanomaterials

The electrochemical sensor is a sensor based on the electrochemical properties of the analyte and converts the chemical quantity of the analyte into electrical quantities for sensing.Because of its characteristics such as fast detection speed,easy operation,high selectivity,low price,simple equipment,etc.,it has been widely used in medicine,food,environment and other fields.Electrochemical enzyme sensors not only have the advantages of electrochemical sensors but electrochemical enzyme sensors can provide electrons that can circulate for glucose oxidase,CYP enzymes,etc.instead of expensive and fragile NADPH.Three electrochemical biosensors based on carbon nanomaterials were constructed in this paper,which are glucose oxidase sensors based on carbon quantum dot reduced graphene oxide?CDs-rGO?composites,CYP2C9 enzyme sensors based on carboxylated multi-walled carbon nanotubes?c-MWCNTs?and the CYP2D6 enzyme sensor based on the carboxylated multi-walled carbon nanotubesThe main research content is as follows:?1?One-step synthesis of carbon quantum dots reduced graphene oxide composites by hydrothermal method using?-cyclodextrin and graphite oxide.After it was modified on glassy carbon electrode?GCE?,glucose oxidase was immobilized by covalent reaction.Finally,theelectrodewassealedwith0.5%Nafionsolution,thusa Nafion/GOD/CDs-rGO/GCE electrochemical enzyme sensor was prepared.The direct electrochemical behavior of this enzyme sensor was studied by cyclic voltammetry?CV?,which showed that the carbon quantum dot reduced graphene oxide composite has good conductivity and biocompatibility.The apparent electron transfer constant of the sensor is1.14 s^-1;Differential pulse voltammetry?DPV?was used to determine the content of glucose in the phosphoric acid buffer solution?PBS?of 0.1 M pH 7.0,with a linear range of 1¹0 mM and the detection limit of 0.52 mM.?2?H₂SO₄:HNO₃?volume ratio 3:1?successfully introduced carboxyl groups on multi-walled carbon nanotubes to prepare carboxylated multi-walled carbon nanotubes?c-MWCNTs?.The prepared carboxylated multi-walled carbon nanotubes were modified on a glassy carbon electrode,and then CYP2D6 was assembled on the electrode by covalent bonding.Finally,Nafion/CYP2D6/c-MWCNTs/GCE sensor was prepared by solid sealing with 0.5%Nafion solution.The direct electrochemical behavior of the sensor was investigated by CV method.It was found that the carboxylated multi-walled carbon nanotubes not only have good electrical properties,but also provide a suitable microenvironment for the CYP2D6enzyme.The apparent electron transfer constant of the sensor is 1.30 s^-1;Simultaneously,the effect of several antidepressants?Paroxetine,fluoxetine,sertraline,fluvoxamine?on the activity of CYP2D6 enzyme in PBS?0.1 M,pH 7.4?containing 20 M dextromethorphan was also studied by DPV method.The inhibitory ability of these antidepressants to CYP2D6 was paroxetine?IC50 1.8?M?>fluoxetine?IC50 3.9?M?>sertraline?IC50 10?M?>fluvoxamine?IC50 22.8?M?.?3?The carboxylated multi-walled carbon nanotubes were prepared using H₂SO₄:HNO₃?volume ratio 3:1?,and CYP2C9/c-MWCNTs/GCE electrochemical enzyme sensors were successfully prepared on the basis of it.The direct electrochemical behavior of this sensor was investigated.The results showed that carboxylated multi-walled carbon nanotubes could promote the direct electron transfer between the active site of CYP2C9 enzyme and the electrode.The apparent electron transfer constant is 2.17 s^-1.The effects of the functional factors?baicalin,luteolin,rutin,quercetin,curcumin,baicalein,puerarin?on the activity of CYP2C9 enzyme were investigated by DPV method in PBS?0.1 M,pH7.4?containing 200 M tolubutyurea.The results showed that the IC50 values of baicalin,luteolin,rutin,quercetin,curcumin,baicalein,and puerarin were 5.54?M,5.96?M,9.30?M,12.05?M,18.39?M,and 19.51?M,187.88?M,respectively.