Electrochemical Immunoassay for Tumor Marker CA19-9 Detection Based on Self-Assembled Monolayer

Abstract

A CA19-9 electrochemical immunosensor was constructed using a hybrid self-assembled membrane modified with a gold electrode and applied to detect real samples. Hybrid self-assembled membranes were selected for electrode modification and used to detect antigens. First, the pretreated working electrodes were placed in a 3-mercaptopropionic acid (MPA)/β-mercaptoethanol (ME) mixture for 24 h for self-assembly. The electrodes were then placed in an EDC/NHS mixture for 1 h. Layer modification was performed by stepwise dropwise addition of CA19-9 antibody, BSA, and antigen. Differential pulse voltammetry was used to characterize this immunosensor preparation process. The assembled electrochemical immunosensor enables linear detection in the concentration range of 0.05–500 U/mL of CA19-9, and the detection limit was calculated as 0.01 U/mL. The results of the specificity measurement test showed that the signal change of the interfering substance was much lower than the response value of the detected antigen, indicating that the sensor has good specificity and strong anti-interference ability. The repeatability test results showed that the relative standard deviations were less than 5%, showing good accuracy and precision. The CA19-9 electrochemical immunosensor was used for the actual sample detection, and the experimental results of the standard serum addition method showed that the RSD values of the test concentrations were all less than 10%. The recoveries were 102.4–115.0%, indicating that the assay has high precision, good accuracy, and high potential application value.

Emerging Biosensing Methods to Monitor Lung Cancer Biomarkers in Biological Samples: A Comprehensive Review

“…Wei et al developed an electrochemical immunosensor for the sensitive detection of CA19-9 using a hybrid self-assembled membrane modified with a gold electrode. The immunosensor responded to CA19-9 in a linear range of 0.05–500 U/mL with a lower detection limit of 0.01 U/mL [ 139 ]. This sensor was used for a real-sample analysis with a standard deviation of less than 5%.…”

Electrochemical and Photoelectrochemical Immunosensors for the Detection of Ovarian Cancer Biomarkers

“…Then, CA 19-9 antibodies were immobilized onto the modified electrode using EDC/NHS chemistry which activated the carboxylic acid groups on the surface of MWCNTs for CA 19-9 antigen detection. Recently, Wei et al [60] described another label-free EC immunosensing method for the detection of CA 199 using piranha pretreated gold electrode. The pretreated electrode was coated with a self-assembled layer of 3-mercaptopropionic acid (MPA) and β-mercaptoethanol (ME) hybrid (MPA/ME/Au).…”