Use of osteocalcin-specific Gpr158 protein in biosensor technology for osteocalcin detection

Abstract

Osteoporosis (OP) constitutes a notable disorder within bone metabolism, characterized by the creation or desorption of porous bone. Osteocalcin (OC), a marker expressed by osteoblasts at various developmental stages, serves as a pivotal biomarker for diagnosing and monitoring osteoporosis. Current methodologies for quantifying OC, such as enzyme-linked immunosorbent assay (ELISA) and analogous antibody-based techniques, suffer from drawbacks including suboptimal thermostability, diminished sensitivity, and elevated manufacturing costs. In this study, a biosensor was engineered for the precise determination of OC, by using the osteocalcin-specific biorecognition receptor Gpr158 for the first time in the literature. A gold nanoparticle-modified gold screen-printed electrode was used as a working electrode, and electrochemical impedance spectroscopy (EIS) was employed as the primary measurement technique as a label-free method. To enhance system sensitivity, the working electrode was modified with fullerene, a carbon-based spherical nanomaterial. Subsequently, the electrode was immersed in sulfuric acid, activating the carbonyl structures on the fullerene, and through EDC/NHS the biorecognition receptor was immobilized with an amide bond. The efficacy of each modification step was evaluated using EIS and scanning electron microscopy (SEM). EIS was also utilized as an indicator method to analyze OC, revealing a linear determination range spanning from 0.5 to 100 ng/mL. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.51 ng/mL and 1.53 ng/mL, respectively. The biosensor, characterized by exceptional reproducibility, consistently yielded accurate results in the measurement of osteocalcin. This innovative approach holds promise as a robust and efficient means for diagnosing and monitoring osteoporosis, showcasing its potential as a valuable tool in clinical applications.