Bone tumor diagnosis: A FRET-based fluorescent osteocalcin sensor using palladium nanoparticles

Abstract

This study was conducted on a design of a fluorescence resonance energy transfer (FRET)-based fluorescent osteocalcin sensor using palladium nanoparticles (PdNPs) and application for determining osteocalcin (OC) level as a bone turnover marker in human serum samples for bone tumor diagnosis. The PdNPs were synthesized via a seed-mediated growth method. The UV-Vis absorption spectrum of PdNPs and the fluorescence-emission spectrum of 5-carboxyfluorescein (FAM)-OC aptamer showed remarkable spectral overlap. FRET experiments were performed using a fixed concentration of 90 nM of FAM-labeled OC aptamer, and results indicated an OC concentration-dependent manner within the range of 5–1200 ng/mL with the limit of detection 0.31 ng/mL. The results showed the high recovery rates ranged from 97.70 % to 99.50 % with relative standard deviations between 3.37 % and 4.31 %, indicating the accuracy and reliability of the nanoprobe. The FRET-based aptamer nanoprobe showed excellent specificity towards OC, with minimal interference from other proteins. Additionally, it exhibited excellent long-term stability and repeatability, maintaining approximately 93.89 % of the initial FRET response after 25 days. These results suggested that the FRET-based aptamer nanoprobe is highly effective, reliable, and suitable for practical applications in clinical diagnostics.