The Study On HIV-1DNA Electro-chemical Sensor

DNA sensor is one of the important detective means and noted widely in recent years for rapid development.DNA sensor takes DNA as sensitive element by immobilizing DNA on the transduser.lt can convert biological signals into physical signals such as light,electrical,acoustic etc. by DNA on the surface of electrode interaction with DNA,RNA,drug and radicals.DNA sensor is widely used in many fields such as illness detection,enviornment monitoring,drug screening, forensic identifying.Traditional diagnostic method on HIV-1 is not suitable for routin environment because of radioisotopes,complex steps and long assay times.We manufactured a kind of high-sensitive DNA electrochemical sensor based on carbon paste electrode which can quantify DNA sequences related to HIV-1 simply in short time.This forms the bases for gene diagnosis on nucleic acid probe electrochemical biosensor.The DNA electrochemical sensor is manufactured by immobilizing ssDNA on the activated surface of CPE in fixed potential.The complementary DNA is detected by hybridization on the this sensor.The conditions on probe immobilizing and hybridizing are studied during analysis.We concluded 2min is the optimal immobilizing time.Hybridization time has great effect on the response.With the hybridization time increasing, difference of reductive peak current of indicator on the electrode increases sharply.Then it increases slowly in 20 minutes.The concentration of NaCl in hybridization solution and hyridizayion potential influence electrochemical response greatly.The concentration of NaCl being between 0.1 and 0.5mol/L,the response increase quickly. It increases slowly when NaCl's concentration is between 0.5 and 0.75mol/L.If this sensor hybridizes in 0.1,0.25,0.75,1.0 and 0.5v respectively,the study show 0.5v is optimal hybridization voltage.Hybridization efficiency without voltage comparing with that in 0.5v,the hybridization quantities for two hours is almost the same as that for 20 minutes in 0.5v.This sensor can be used for the identification and detection of DNA sequences related to HIV-1.When the concentration of the comlementary DNA is between1.25×10-7and 5.0×10-7mol/L,the response is linear with their concentrations.The lowest detection limit for this sensor is 40ng/ml.The selectivity of indicator is studided using Co(bpy)3(ClO4)3and DNM as indicator.The experimental results show that we can complete a circle of detection by quantifying and quanlitying complementary DNA using Co(bpy)3(ClO4)3 as indicator. The binding condition of Co(bpy)3(ClO4)3 is optimised.The sensitivity of sensor is high when the concentration Co(bpy)3(ClO4)3 of is 9.1#10-5 mol/L.The optimal binding time of indiator is 2min.