Ratiometric Fluorescent Sensing of MMP-3 via FRET for Postoperative Rehabilitation Assessment and Prognostic Monitoring Following Joint Surgery.

Matrix metalloproteinase-3 (MMP-3) is a critical biomarker for inflammatory responses and tissue remodeling following joint surgery. Here, we developed a ratiometric fluorescence probe based on fluorescence resonance energy transfer (FRET) for sensitive and selective detection of MMP-3 activity. The probe comprises CdTe quantum dots (R-QDs) as the energy donor and BHQ as the acceptor, linked by an MMP-3-cleavable peptide. Upon MMP-3 cleavage, the FRET process is disrupted, resulting in fluorescence recovery at 540 nm, while the reference signal at 690 nm remains constant, enabling ratiometric quantification. The probe exhibits a linear response from 20 to 100 nM with a detection limit of 7.8 nM and excellent selectivity against other MMPs and interfering proteins. Clinical validation using serum samples from 11 subjects (5 healthy controls and 6 post-surgery patients) successfully distinguished patients from controls. Moreover, real-time monitoring of 6 patients over 18 days post-surgery revealed a clear correlation between MMP-3 levels and rehabilitation progress. These results demonstrate that our ratiometric FRET probe holds promise for postoperative rehabilitation assessment and prognostic monitoring following joint surgery.