Study On Nanomaterial-based Electrochemiluminescence Biosensor For Detecting Glucose And Concanavalin A

Electrochemiluminescence?ECL?is chemiluminescence triggered by electrochemical processes,which combines the advantages of chemiluminescent analysis with electrochemical analysis,and exhibits wide detection range,controlled reaction system,short time consumption,and high sensitivity and signal-to-noise ratio.ECL has been used extensively as a detection method in biosensing.In recent years,nanomaterials have been received considerable attention and widely applied in fixing biological materials and electrocatalysis,because of their outstanding electrochemical activities,high catalytic activity,large specific surface area and excellent biocompatibility.Combining the advantages of ECL biosensor and nanomaterials,several ECL biosensors were constructed for detecting glucose and concanavalin A in this study.The detailed researches are listed as follows.1.A novel non-enzymatic electrochemiluminescence sensor for the detection of glucose based on the competitive reaction between glucose and phenoxy dextran for concanavalin A binding sitesA non-enzymatic electrochemiluminescence?ECL?sensor based on the competitive reaction between glucose and phenoxy dextran?Dex P?for concanavalin A?Con A?binding sites was constructed for detecting glucose.The hybrid of graphitic carbon nitride nanosheet and 3,4,9,10-perylenetetracarboxylic acid?g-C₃N₄-PTCA?as signal probe was modified onto the glass carbon electrode?GCE?for immobilizing Dex P through ?-? interaction.Then,Con A was incubated onto the electrode via the specific binding between Con A and Dex P.When the modified electrode was immersed into glucose solution,glucose would compete with Dex P for Con A.With the increase in the concentration of glucose,the more Con A was taken away from the electrode, resulting in a gradual increase in ECL intensity,thus,achieving the determination of glucose.The linear range was 1.0×10^-10⁵.2×10-5 mol·L^-1 and the detection limit was4.0×10^-11 mol·L^-1?S/N = 3?.Moreover,this sensor possessed high sensitivity,good stability and reproducibility,indicating a promising development of non-enzymatic ECL glucose sensor.2.A novel “on-off” electrochemiluminescence sensor for the detection of concanavalin A based on Ag-doped g-C₃N₄In this work,a novel “on-off” electrochemiluminescence?ECL?biosensor was successfully constructed for ultrasensitive detection of concanavalin A?Con A?.The“signal-on” state with strong initial ECL signal was obtained by Ag-doped graphitic carbon nitride nanosheet?Ag-g-C₃N₄?,which was modified onto the glassy carbon electrode?GCE?for immobilizing phenoxy dextran?Dex P?through ?-? interaction.Then,the target Con A was anchored onto the Dex P/Ag-g-C₃N₄ modified film via the specific carbohydrate-Con A interaction.Successively,polyaniline-3,4,9,10-perylenetetracarboxylic acid-Dex P conjugate?denoted as PANI-PTCA-Dex P?,as the ECL signal quenching probe,was incubated onto the electrode through the carbohydrate-Con A interaction to achieve the “signal-off” state.Here,PTCA was used as a matrix for the high loading of PANI and Dex P,PANI served as the quencher towards Ag-g-C₃N₄ system,and Dex P as the recognition element for bounding Con A.With the formation of the sandwiched structure of Dex P,Con A and PANI-PTCA-Dex P,a desirable quenching ECL signal was measured with S2O82-as the co-reactant of Ag-g-C₃N₄.The quenching effect of PANI towards Ag-g-C₃N₄ is positively correlated with the concentration of Con A.With such an “on-off” system,the detection of Con A was achieved with a wide linear range from 0.0010 ng·m L^-1 to 50 ng·m L^-1 as well as a low detection limit down to 0.00030 ng·m L^-1.3.An ultrasensitive electrochemiluminescence biosensor for the detection of concanavalin A based on Au nanoparticles-thiosemicarbazide functionalized Pt Ni nanocubes as signal enhancerA sandwich-configuration electrochemiluminescence?ECL?biosensor was constructed for detecting concanavalin A?Con A?based on peroxydisulfate/oxygen?S2O82-/O2?system.In this work,the gold nanoflower modified Zn-doped Sn O2 was used as a substrate to adsorb recognition element horseradish peroxidase?HRP?for binding Con A.Then,Au nanoparticles-thiosemicarbazide functionalized Pt Ni nanocubes?Au NPs-TSC-Pt Ni NCs?,as a novel ECL signal tracer,were incubated onto the electrode through a specific carbohydrate-Con A interaction,thus achieving a sandwiched structure.The integration of amplifying effect of both TSC and Pt Ni NCs on the ECL of S2O82-/O2 system endowed the biosensor a high sensitivity.The linear range for Con A detection was from 0.0010 ng·m L^-1 to 10 ng·m L^-1 with a detection limit of 0.00020 ng·m L^-1?S/N = 3?.