Multichannel Plasmonic Point-of-Care Device for Salivary Detection of Periodontal MIP-1α: Analytical Comparison with ELISA

Introduction: Salivary biomarkers are increasingly gaining trust as promising candidates for the non-invasive diagnosis of periodontal diseases and the monitoring of periodontal tissue health. This study investigated the analytical capabilities of a multichannel, plasmonic point-of-care (POC) test based on optical fiber technology for detecting and quantifying salivary macrophage inflammatory protein-1 alpha (MIP-1α), using enzyme-linked immunosorbent assay (ELISA) as a comparison.
Methods: Three plastic optical fibers (POFs) were functionalized with a self-assembled monolayer (SAM) containing MIP-1α antibodies. The POFs were placed between a spectrometer and a light source to monitor refractive index shifts at the POF-SAM interface, corresponding to the occurrence of surface plasmon resonance (SPR) during antigen–antibody interaction. A dose–response curve was generated using a range of MIP-1α concentrations. Salivary samples were collected from a cohort of fifty participants and analyzed using both the SPR-based biosensor and ELISA. Spearman’s Rank test assessed the correlation between the two techniques. Differences in MIP-1α expression were further analyzed in relation to clinical variables, including periodontal status, age, and gender (Mann–Whitney U-test).
Results: A significant correlation was observed between the measurements obtained from the biosensor and those from ELISA. The sensitivity of the SPR-POF device allowed for the detection of MIP-1α at lower concentrations than ELISA. Patients with periodontal disease exhibited significantly higher levels of MIP-1α compared to those without the disease, supporting its potential as a diagnostic biomarker.
Conclusions: The developed three-channel plasmonic POCT exhibited comparable accuracy and superior sensitivity to ELISA for detecting salivary MIP-1α. Moreover, the multichannel plasmonic configuration enhanced both measurement efficiency and the reliability of the results.