Preparation,Characterization And Evaluation Of Latex Enhanced Immunoturbidimetric Reagent For Determining Carcinoembryonic Antigen

As a broad-spectrum tumor marker,CEA has important clinical significance in pre-tum screening,tumor staging,invasion and metastasis,and postoperative recovery.At present,the determination of carcinoembryonic antigen is mostly chemiluminescence method and enzyme-linked immunoassay.The former has higher cost and higher requirements for instruments,while the latter is cumbersome and labor-intensive,and the results are not conducive to repetition.By contrast,latex enhanced immunotobidimetry method has many advantages such as low cost and good repetition.Therefore,we intends to develop a reagent for carcinoembryonic antigen determination by latex enhanced immunoturbidimetry which based on the existing technology.Firstly,the immune latex was prepared by covalent coupling of JSR 300 nm carboxylated latex microspheres with Hytest monoclonal antibody,and the coupling process was systematically studied.The optimum conditions of latex reagent reaction system were screened by further detection on Hitachi 7180 automatic biochemical analyzer.The results showed that when the two antibodies were coupled with latex microspheres,the concentration of EDC was 4%,the reaction buffer system was pH 7.4 PBS buffer,the coupling time was 2 h,2mg JSR 300 nm microspheres and the amount of antibody protein was 0.4 mg.The prepared latex reagent had the best sensitivity and linearity;the optimal conditions of the reagent reaction system were as follows:detection wavelength is 570 nm,50 ?L 0.25%latex reagent,200 ?Ll R1,10?L sample,wherein 2%NaCl,0.1%Surfactant and 4%PEG6000 were added to R1.Secondly,in this paper,the morphology,particle size,distribution and potential of immune latex were studied by transmission electron microscopy(TEM),dynamic light scattering(DLS)and Zeta-potential analysis.The results of electron microscopy showed that the latex microspheres could maintain a uniform distribution after covalent coupling with the antibody protein,and there was no agglomeration.The dynamic light scattering results showed that the antibody protein was stably coupled to the surface of the microspheres.Zeta-potential measurement showed that the latex microspheres still have good stability after covalent coupling with the antibody protein.Finally,a part of the performance of the latex reagent was evaluated,including the calibration curve of the reagent,blank absorbance,linear range,precision,analytical sensitivity and correlation with chemiluminescent reagents.The results all met the clinical testing requirements.