Salivary extracellular vesicles and Raman spectroscopy in precision diagnostics of type 2 diabetes

Type 2 Diabetes (T2D) remains a major global health issue, driven by sedentary lifestyles and aging populations, emphasizing the urgent need for precise diagnostics that allow early detection and personalized monitoring. Traditional blood tests, including glucose and HbA1c measurements, offer limited temporal and molecular information. In contrast, saliva provides a non-invasive, easily accessible biofluid that reflects systemic metabolic changes. Its molecular components, especially extracellular vesicles (EVs), such as exosomes and microvesicles, contain proteins, lipids, and microRNAs directly associated with insulin resistance, β-cell dysfunction, and inflammation in T2D. Advances in Raman spectroscopy and surface-enhanced Raman scattering (SERS) now enable high-sensitivity, label-free molecular fingerprinting of salivary EVs, supporting multiplex detection of disease-related biomarkers. Combining Raman-based sensing with EV profiling introduces an innovative approach for non-invasive, precision diabetes diagnostics. This review explores the diagnostic importance of salivary EVs, recent developments in Raman/SERS-based biomolecular detection, and the clinical potential of integrating these technologies for early screening and therapy monitoring. Moreover, incorporating artificial intelligence (AI) for spectral analysis and developing portable Raman devices could facilitate real-time, saliva-based metabolic monitoring, advancing personalized, preventive, and patient-focused diabetes care.