Development of a smart sensing system for early detection of osteoporosis

Early detection of any disease is essential for an efficient treatment. Bone loss can be detected and monitored by regular measurement of serum or urine C-terminal telopeptide of type 1 collagen (CTx-I). Therefore, rapid, sensitive, accurate, portable and low-cost point-of-care devices are highly desirable. In this research, we have proposed a selective, sensitive, quick and inexpensive Internet of Things (IoT)-based device for the quantification of CTx-I levels in serum. A capacitive interdigital sensor with multi-sensing electrode configuration was employed to perform the experiments. Initially, natural antibodies were used to introduce selectivity for the target molecule. In spite of the high selectivity and sensitivity of the proposed system, there were some limitations in using natural antibodies. Natural antibodies are very expensive, sensitive to harsh environmental conditions and have limited stability. In order to overcome these limitations, the interdigital sensor was coated with artificial antibodies, prepared by molecular imprinting technology. Electrochemical impedance spectroscopy was used to evaluate the resistive and capacitive properties of the sample solutions. A microcontroller-based system was developed for the measurement of the level of CTx-I in serum and for data transmission to an IoT-based cloud server. The data can be provided to the medical practitioner and a detailed investigation can start for early detection and treatment. The developed sensing system responded linearly in a range of 0.1 ppb to 2.5 ppb, which covers the normal reference range of CTx-I in serum, with a limit of detection (LOD) of 0.09 ppb. The results demonstrated that the proposed portable biosensing system could provide a rapid, simple and selective approach for CTxI measurement in serum. Sheep serum samples were tested using the proposed system and the validation of the results was done using an enzyme-linked immunosorbent assay (ELISA) kit.