Label-free saliva screening platform using M13 bacteriophage-based 3D plasmonic structures for MRONJ diagnosis

Medication-related osteonecrosis of the jaw (MRONJ) is a severe complication associated with antiresorptive or antiangiogenic agents, often leading to pain, infection, and reduced quality of life. Current imaging-based diagnostics have limitations in detecting lesions smaller than 10 mm. In this study, we propose a label-free saliva screening approach for MRONJ diagnosis using a three-dimensional plasmonic structure based on M13 bacteriophage. Raman spectroscopy was employed to detect metabolite alterations in saliva, which are known to be associated with MRONJ. The M13 bacteriophage facilitates controlled interparticle gap of gold nanoparticles, thereby increasing hotspot density and enhancing Raman signal intensity. Data preprocessing was conducted on saliva Raman spectra collected from MRONJ patients and controls. To filter outliers, we computed Pearson correlation coefficients between each spectra and the group mean and excluded those with coefficients lower than 0.9. A total of 90 spectra were classified using an optimized multi-layer perceptron model, yielding a specificity of 84.6%, sensitivity of 100.0%, and an AUC of 0.92. This study demonstrates the potential of a saliva-based, non-invasive MRONJ screening strategy. Subsequent research should expand clinical datasets and investigate broader diagnostic applications.