Biotinylated aptamer-based SPR biosensor for detection of CA125 antigen

Carbohydrate antigen 125 (CA125) is used for the prediction of the risk of ovarian malignancy algorithm value as an early diagnosis algorithm of ovarian cancer (OC). Hence, the detection of OC in the early stage requires techniques with high sensitivity and specificity. This work presents the development of a highly sensitive and specific aptamer-based SPR biosensor for the detection of CA125 antigen. A biotinylated CA125 aptamer (Ap) was immobilized onto a streptavidin-coated gold chip by affinity capture. Parameters affecting the response such as temperature, flow rate, and pH of flow buffer were optimized, and bioanalytical method validation elements were calculated. The linear range of the system response was 10-100 U mL-1, and the limit of detection (LOD) was found to be 0.01 U mL-1. The results affirmed that both precision and accuracy were lower than 15% for each concentration of CA125, and its recoveries were in the range of 97.5-105%. Therefore, the precision, accuracy, and recovery were acceptable for the determination of CA125 using the developed aptabiosensor. The developed Ap-based SPR technique was highly efficient for the clinical measurement of CA125 in human serum samples. In conclusion, the developed aptasensor can be an alternative for the screening and early detection of OC.