| Research BackgroundAcute myocardial infarction(AMI)is the onset of pathological myocardial ischemic necrosis and it is a life—threatening emergency due to its rapid onset,high fatality rate,and poor prognosis.Clinically,the elevation of myocardial markers in serum(cardiac troponin I,creatine kinase isoenzyme MB and myoglobin)are of great significance for the diagnosis of AMI.Although some traditional detection methods,such as enzyme-linked immunosorbent assay or electrochemiluminescence assay(ECLA),have high sensitivity in detection,those were restricted by their auxiliary equipment and time consuming.The method of immunochromatography(ICT)based on point-of-care(POCT)technology is widely used in the primary and emergency departments due to its advantages of portability,speed,accuracy,and ease of operation.The most mature commercialization of this method is fluorescence immunochromatography test(FICT).Nowadays,this technology has limited its further application due to the high background,light interference and fluorescence quenching.Recently,ICT technology based on magnetic nanobeads(MNBs,magnetic nanobeads)has been interested by many researchers because of its high signal—to—noise ratio,large surface area of large antibody coupling,and stable magnetic signal.It has broad application prospects.Method and purposeIn this study,MNBs were coupled with capture monoclonal antibodies to construct immunomagnetic probes for cTnl,CKMB and Myo.An immunochromatographic test strip of the corresponding marker was prepared by immobilizing a monoclonal antibody on a nitrocellulose membrane.In addition,by screening and combining the diluent components and their concentrations,a standard antigen dilution solution for magnetic immunochromatography was finally developed.Using the standard magnetic detection equipment,the standard curve method was used to obtain the standard curve of the three markers required for this study,and used for quantitative detection of clinical samples.Finally,the purpose of rapid,accurate and quantitative detection of the three markers of myocardial infarction in clinical specimens is achieved.Result1.The detection time of the magnetic immunochromatographic test strip prepared in this study was 25 minutes,and the lower limit of quantification was finally obtained:0.03 ng/mL for cTnI,0.21 ng/mL for CKMB,and 0.17 ng/mL for Myo,with 5 orders magnitude of dynamic linear detection range.2.The standard antigen dilution buffer developed in this study was confirmed to be used to shorten the detection time,stabilize the antigen activity,and enhance the stability of the beads.3.The clinical test of 110 serum samples showed that the magnetic immunochromatography test(MICT)have similar sensitivity and specificity to the ECLA method(Pearson correlation coefficient:0.994 for cTnI,0.981 for CKMB,0.990 for Myo,P<0.01).Compared with the commercial FICT,the positive detection rate showed no significant difference and the consistency was good CMcnemar test,P<0.01,Kappa was more than 0.75).4.The recovery rates of cTnl,CKMB and Myo were 95.40%—101.36%,97.8%—105.4%and 95.9—103.9%(n= 5),respectively.The relative standard deviation of the recovery rates was all lower than 10%.ConclusionIn this study,a magnetic probe-based immunochromatographic test strip was successfully constructed to realize the combined and rapid detection of three myocardial infarctions,with high sensitivity,specificity and wide dynamic detection range.As a complementary method for in vitro diagnosis,magnetic immunochromatography has great potential in immunochromatography. |
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