Abstract: Serum C-terminal telopeptide of type I collagen (CTx-I) assays quantify the fragment of CTx-I released throughout the procedure of bone remodeling. CTx-I is a key bone turnover biomarker where any variation in the level of CTx-I can be an indication of increased bone resorption. This study focuses on a new strategy for the prognosis of bone loss by monitoring the concentration of CTx-I in serum. An interdigital capacitive sensor together with Electrochemical Impedance Spectroscopy (EIS) was employed to assess the dielectric properties of the test solution. Artificial antibodies have been prepared for CTx-I molecules using the molecular imprinting technique. The sensor was functionalized using the synthesized Molecular Imprinted Polymer (MIP) in order to introduce the selectivity of CTx-I biomarker to the sensor. Calibration experiments were performed using different known concentration of sample solutions. The proposed biosensor showed a good linear response between 0.1 and 2.5 ng/ml. The detection limit of 0.09 ng/ml was found, encompassing the normal reference ranges required for recognition of bone turnover. Unknown real serum samples obtained from sheep blood were analysed using the proposed biosensor. The validation of the suggested technique was done using enzyme-linked immunosorbent assay (ELISA). The developed biosensor exhibited a good correlation with ELISA
Author keywords: C-terminal telopeptide, Electrochemical impedance spectroscopy, Interdigital sensors, Molecular imprinted polymer, Osteoporosis