DNA Sensor Based On Poly-thionine And Gold-Prussian Blue Nanoparticles And Phenol Detection

DNA biosensor has good performance,for example,rapid,sensitive,simple operation and low cost.It has very broad application prospects in clinical diagnosis,food testing,environmental monitoring and other fields.In recent years,in order to improve the sensitivity,selectivity and stability of the biosensors,A variety of conductive polymers and nanomaterials was employed in the biosensors.In this paper,the materials with excellent properties on the above were applied to research the DNA sensor based on PTh and GN-PB and its application in detection of cDNA and phenol.An effective method of detection of phenol pollutants was established.The main contents of this paper are as follows.(1)Electrochemical DNA sensor based on PTh and GN-PBIn this part,two different DNA sensors were prepared.PTh modified electrode was prepared on the surface of a glassy carbon electrode(GCE).GN-PB and GNPs were deposited on PTh/GCE,respectively.DNA probe was immobilized by Au-NH2 bond and the DNA sensor was fabricated(ssDNA/GNPs/GN-PB/PTh/GCE).The preparation process of the sensor was characterized by cyclic voltammetry and electrochemical impedance spectroscopy.The other sensor is thinoine(Th)as the based film on the glassy carbon electrode.GN-PB and GNPs were deposited on Th/GCE.At last,DNA probe was immobilized to fabricate ssDNA/GNPs/GN-PB/Th/GCE.Differential pulse voltammetry(DPV)and electrochemical impedance spectroscopy(EIS)was employed to detecte the complementary DNA(cDNA)by two kinds of sensors.By contrast,the sensor(ssDNA/GNPs/GN-PB/PTh/GCE)has higher sensitivity,wider linear range and higher stability.(2)Electrochemical phenol sensor based on PTh and dsDNAMB can be embedded in double stranded DNA.In the present of phenol,the phenol and MB have a competitive effect and cause the signal of MB decreased.Based on this principle,an electrochemical phenol sensor based on PTh and dsDNA was designed.Electro polymerization of Th on the surface of GCE.GN-PB and GNPs were deposited on Th/GCE,respectively and immobilize dsDNA.An electrochemical phenol sensor was fabricated.In this paper,the electrochemical behavior of the MB indicator embedded in dsDNA was characterized.The synergistic effect between MB and[Fe(CN)6]3-/4-was studied.Finally,the phenolic wastewater from pharmaceutical factory was tested.The results showed that,the peak current of MB and the concentration of phenol showed good linear relationship in the range of 1×10-3?1×10-8 mol/L.The correlation coefficient is above 0.99 and the detection limit is found to 7×10-9mol/L.The reproducibility,consistency and anti-interference ability of the sensor were investigated in the experiment.The RSD of sensor was 2%.The consistency was well,and has anti-interference ability.Finally,the sensor is applied to the detection of the actual samples of the wastewater containing phenol.It is almost identical to the determination of phenol by UV spectrophotometry.and can be used for the detection of trace phenol.