An Electrochemical Biosensor Based on AuNP-Modified Gold Electrodes for Selective Determination of Serum Levels of Osteocalcin

This paper reports a step-wise protocol to immobilize corresponding antibody on gold electrodes for electrochemical measurement of Osteocalcin (Oc), a bone turnover marker, levels in human serum. To our knowledge this is the first such sensor developed for Oc measurement. The magnitude of electrochemical response current was linearly dependent on Oc concentration with an R square of 0.99. The detection limit was calculated to be 0.65 ng/mL. The sensor was capable to assess antigen levels of 2.5-90 ng/mL. The correlation between our sensor results and that of electrochemiluminescence (ECLIA), the current state-of-art, was also investigated and the results showed a high correlation (slope of 0.97 and R
²
of 0.98) between the two systems. This is while the total assay time for the Oc sensor is about 5 min and ECLIA needs several hours to be performed.