| The research background and purposeCarcinoma of the lungs,one of the most common malignant tumors worldwide,is the major cause of cancer-related deaths.Most patients(more than 75%)are in middle-advanced stage when diagnosed,therefore,optimal therapeutic opportunities are unavailable.Furthermore,the 5-year survival rate of patients with lung carcinoma is particularly low(about 15%).Small cell lung cancer(SCLC),the most malignant subtype of lung cancer,develops very fast and metastasizes in the early stage,resulting in very poor prognosis.In addition,SCLC is sensitive to radiation treatment and chemotherapy and if diagnosed at an early stage.At present,the detection of serum tumor markers has been used for Screening,diagnosis and evaluation of prognosis of lung cancer.Neuron specific enolase(NSE)is a sensitive and specific marker associated with SCLC.Carcinoembryonic antigen(CEA)has been used as a tumor marker in a variety of tumors,and plays an important role in the diagnosis and prognosis of lung cancer.30%to 70%of patients with lung cancer have abnormally high levels of CEA.The simultaneous detection of NSE and CEA may improve the accuracy of lung cancer diagnosis.The traditional methods to detect NSE and CEA are enzyme-linked immunosorbent assay and electrochemical immunoassay chemiluminescence analysis.These two methods have high sensitivity,but these techniques require large and expensive instruments,complex operations,long analysis time and professional expertise,which results in poor application in primary or community hospital,early screening.especially in selecting patients with lung cancer out of the general populations.The immunochromatographic assay(ICA)is a popular immunoassay technology that can rapidly provide in vitro diagnostic results.The immunochromatographic assay usually utilizes colloidal gold,fluorescent material or nano silver particles as its label.In the process of the assay,the label and the analyte reaction to form an immune-complexes,and the complexes were captured by corresponding ligand and enriched in the detection zone of nitrocellulose membrane.The assay was qualitative or quantitative analysis by the color depth and reflecting light intensity of detection area.Due to the absence of a magnetic background and photo-bleaching in analyte samples,the LFTS based on magnetic nanoparticles exhibit a high "signal-to-noise"ratio and maintain a stable signal compared to the color-based or optical-based LFTS.The LFIA provides quantitative results by measuring the magnetic signal of the test zone using a magnetic assay reader,which improves the sensitivity and provides a better means of quantification.The research methodsTo obtain the immunomagnetic probes,immobilization of antibodies were carried out by the classical EDC/NHS method.Optimize the preparation of corresponding immune chromatography test strip to testing different concentrations of antigen and clinical serum samples.The matching magnetic assay reader was used for quantitative analysis and then the sensitivity,specificity and accuracy of this assay were evaluated.The research resultThe test strip can be used for rapid,quantitative detection of NSE and CEA,and it shows the advantages of good specificity and high sensitivity(the detection limit is 0.094ng/mL for NSE and 0.045ng/mL for CEA).One hundred thirty clinical samples were detected by the test strip,which had a high degree of consistency with the electrochemiluminescence immunoassay kit(n= 30,R2>0.990,P<0.001).The conclusion of the researchThis immunomagnetic nanobeads-based immunochromatography test strip which show high sensitivity and good specificity,had been fabricated successfully,and it could be used for the quantification of NSE and CEA.In addition,this test strip,as an effective supplementary means to realized rapid screening of lung cancer,could be used in community clinics and family physicians. |
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