Different analytes have been proposed as biomarkers of periodontitis, such as macrophage inflammatory protein (MIP-1α) and matrix metalloproteinase-8 (MMP-8). The aim of this proof-of-concept study is to test a novel highly sensitive point-of-care test (POCT), based on an optical biosensor exploiting the principles of surface plasmon resonance (SPR), for the analysis of salivary MIP-1α and MMP-8.
Antibody self-assembled monolayers (SAMs) for plasmonic detection of MIP-1α and MMP-8 were realized on suitably modified plastic optical fibers. Biomarker levels were quantified by analysing the shift of the resonance wavelength of a white light source determined by the specific antigen-antibody binding upon the SAM and detected by a spectrometer connected to the biosensor.
Dose-response curves were realized by serial dilutions of human recombinant MIP-1α and MMP-8 in both PBS (phosphate buffered saline) and real matrix (saliva), showing a very low limit of detection (LOD) and a high selectivity. It was also possible to discriminate, by measuring the biomarker salivary levels, between a periodontitis patient and a periodontally healthy subject.
The present SPR-based POCT demonstrated to be employable to detect and quantify MIP-1α and MMP-8 levels in both buffer solution and saliva with low LOD and high selectivity, opening interesting perspectives for future clinical applications in terms of on-site detection and real-time monitoring of periodontal health conditions, early diagnosis, as well as timely and targeted therapy of periodontitis.