The current study has focused on electrochemical immunosensing of carcinoembryonic antigen (CEA) employing an immobilized antibody on a thionine, chitosan, or graphene oxide nanocomposite modified glassy carbon electrode (anti-CEA/THi-CS-GO/GCE) as an indicator of cancer monitoring. THi-CS-GO nanocomposites were made using ultrasonication, and analyses of their morphology and crystal structure using SEM, FTIR, and XRD showed that thionine and chitosan molecules were intercalated with stacking interactions with both the top and bottom of GO nanosheets. Electrochemical experiments revealed anti-CEA, THi-CS-GO/GCE to have exceptional sensitivity and selectivity towards CEA compounds. The detection limit value was established to be 0.8 pg/mL when it was discovered that variations in the decrease peak current were directly proportional to the logarithm concentration of CEA over a wide range from 10-3 to 104 ng/mL. Results of testing the immunosensor's application capability for detecting CEA in a sample of human serum show that ELISA and DPV results are very congruent. The produced immunosensor demonstrated adequate immunosensor precision in determining CEA in prepared genuine samples of human serum and clinical applications.
Pleural effusion is a common diagnostic problem. The analysis of serum and pleural fluid for tumour markers is widely used as a diagnostic aid in clinical practice. The aim of the present study was to determine the usefulness of simultaneous quantification of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA-125) in distinction of malignant from benign effusion. Data from a total of 78 patients including 53 patients with benign and 25 patients with malignant effusion was evaluated. The cut-off values for differentiating benign from malignant effusions were determined using results obtained from patients with known benign effusions (mean + 2 SD, 95% confidence interval). The cut-off for CEA and CA-125 were 5.1 ng/ml and 1707 IU/ml respectively. CEA assay in pleural fluid had an acceptable sensitivity and good specificity of 64% and 98% respectively. CA-125 had a sensitivity of 36% and specificity of 94%. The combination of the two tumour markers gave a sensitivity of 72% and specificity of 92.4%. We suggest a good clinical strategy may be to begin with CEA measurement (assay specificity 98%); if CEA is below the cut-off value (negative), CA-125 could then be measured to improve the sensitivity of detection of malignant effusions. However, measurement of these tumour markers is not cost effective from the point of view that it does not give information on the type of malignancy present. The latter has to be determined either by histological or cytological study.
In this study, a disposable and simple electrochemical immunosensor was fabricated for the detection of carcinoembryonic antigen. In this method, silver nanoparticles (AgNPs) were mixed with reduced graphene oxide (rGO) to modify the surface of screen-printed carbon electrode (SPE). Initially, AgNPs-rGO modified-SPEs were fabricated by using simple electrochemical deposition method. Then the carcinoembryonic antigen (CEA) was immobilized between the primary antibody and horseradish peroxidase (HRP)-conjugated secondary antibody onto AgNPs-rGO modified-SPEs to fabricate a sandwich-type electrochemical immunosensor. The proposed method could detect the CEA with a linear range of 0.05-0.50µgmL-1 and a detection limit down to 0.035µgmL-1 as compared to its non-sandwich counterpart, which yielded a linear range of 0.05-0.40µgmL-1, with a detection limit of 0.042µgmL-1. The immunosensor showed good performance in the detection of carcinoembryonic antigen, exhibiting a simple, rapid and low-cost. The immunosensor showed a higher sensitivity than an enzymeless sensor.