ABSTRACT
Based on the electrochemiluminescence and magnetic suspension immunoassay strategy, a new magnetic graphene and paper-based screen-printed electrode ( SPE ) electrochemiluminescence sandwich immunoassay was developed by combination of the unique physical and chemical properties of magnetic graphene and the advantages such as low cost and low-volume sample consumption of paper-based SPE. Taking human IgG as the model analyte, EDC/NHS method was used to couple capture antibody ( Ab1 ) and magnetic graphene, and direct labeling method was used to label signal antibody ( Ab2 ) with Ru NHS ester. Nonspecific adsorption was highly reduced by the magnetic suspension sandwich immunoassay strategy, and the concentration information of the analyte was obtained by paper-electrochemiluminescence detection. Experimental study of immobilization and labeling effect of Ab1 and Ab2 showed that the magnetic graphene not only improved the load of immune substances, but also promoted the electron transfer. The developed magnetic suspension and paper-based electrochemiluminescence immunoassay could realize the quantitative detection of IgG and had certain application prospect in low cost and rapid immune detection field.
ABSTRACT
Based on the electrochemiluminescence and magnetic suspension immunoassay strategy, a new magnetic graphene and paper-based screen-printed electrode ( SPE ) electrochemiluminescence sandwich immunoassay was developed by combination of the unique physical and chemical properties of magnetic graphene and the advantages such as low cost and low-volume sample consumption of paper-based SPE. Taking human IgG as the model analyte, EDC/NHS method was used to couple capture antibody ( Ab1 ) and magnetic graphene, and direct labeling method was used to label signal antibody ( Ab2 ) with Ru NHS ester. Nonspecific adsorption was highly reduced by the magnetic suspension sandwich immunoassay strategy, and the concentration information of the analyte was obtained by paper-electrochemiluminescence detection. Experimental study of immobilization and labeling effect of Ab1 and Ab2 showed that the magnetic graphene not only improved the load of immune substances, but also promoted the electron transfer. The developed magnetic suspension and paper-based electrochemiluminescence immunoassay could realize the quantitative detection of IgG and had certain application prospect in low cost and rapid immune detection field.
ABSTRACT
Objective:To improve the sensitivity and the linear range of electrochemical immunosensor to detect Schistosoma japonicum (S.japonicum) antibody.Methods:Carbon inks and silver/silver chloride inks were printed on a polyethylene terephthalate (PET) board to make a two-electrode test strip,where carbon was the working electrode and S.japonicum soluble egg antigen (SEA) was fixed at one end of working electrode by different methods; silver/silver chloride electrode was used as control.We tested the valency of the antibody by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in an electrochemistry workstation,and conducted comparison with the results of ELISA.Two new immunosensing electrodes have been developed,based on glutaraldehyde cross-linked (GA) or chitosan-glutaraldehyde cross-linked (Chit-GA) transducer fixing S.japonicum antigen.We tested the titer of the antibody by means of CV and DPV.Results:Our experimental S.japonicum antigen (50 μg/L) is the optimal test concentration for the GA sensor,and 10 μg/L for Chit-GA sensors.The immune reaction time of both electrodes is all essentially complete in 1 minute.The linear range for S.japonicura antibody in human positive serum sample detection by the glutaraldehyde cross-linked immunosensor is 1∶1000 to 1∶400,and by the chitosan-glutaraldehyde cross-linked immunosensor is 1∶1000 to 1∶500.As the concentration of dilution ratio of S.japonicum antibody in human positive serum sample increased,the test value of DPV increased proportionally.Conclusion:GA sensor and Chit-GA cross-linked S.japonicum sensors have high sensitivity and broad linear range response,and both exhibited a good linear relationship between the DPV signal and the test antibody titer.
ABSTRACT
Aim To establish the rapidly detecting method of glucose concentration in brain microdialysate.Method Using high-performance liquid chromatography (HPLC) with electrochemical detector (ED) and Nano-Copper screen-printed electrode (NCSE100)-Flow injection analysis the glucose concentration in brain microdialysate were detected.Result The related coefficient (r) of glucose standard curve was 0.9995. The variation coefficient (CV) within a day was 4%~7%. The striatum extracellular glucose concentration in rats was(2.4?0.8) mmol?L-1. These results indicated that our method was reliable.Conclusion Using HPLC with ED, NCSE100, and flow injection analysis the glucose concentration in brain microdialysate were detected, which has certain applied worth.