Detection of Osteocalcin in Serum Based on Electrochemical Sensing Technology

Osteocalcin is a very useful potential biomarker to be used in the evaluation of multiple myeloma. This work constructs a competitive electrochemical immunosensor that enables the optimization and reapplication of osteocalcin direct competition ELISA at the electrode interface. Glutaraldehyde is commonly used as a bifunctional reagent. The two aldehyde groups within its structure can form Schiff bonds with the amino groups on the protein surface, which can enhance the interfacial adsorption and improve the interfacial binding of immobilized encapsulants. The present work was carried out by electrochemical methods. In this work, bovine serum albumin-osteocalcin immobilized antigen was used as the recognition element at the glassy carbon electrode interface, while osteocalcin antibody was added with the osteocalcin to be measured, and finally the antibody capture at the modified interface was determined by electrochemical methods. The signal sensitivity of this sensor is higher than that of ELISA, because of it eliminating the recombination process of the enzyme-labeled secondary antibody and theoretically reducing the possibility of introducing errors. The sensor provides linear detection of osteocalcin in the range of 2.0 ng/mL similar to 1250 ng/mL with a detection limit of 2.0 ng/mL. The sensitivity and stability of this sensor are excellent, and the established method can detect osteocalcin in real samples.