Liquid saliva analysis using optofluidic photonic crystal fiber for detection of oral potentially malignant disorders

Oral potentially malignant disorders (OPMD) serve as early indicators of oral cancer. These conditions require reliable, non-invasive and real-time diagnostic methods for effective detection and screening. Saliva, as an easily accessible and non-invasive biofluid, has emerged as a promising tool to detect OPMD-associated biomarkers. This proof-of-concept study investigated the application of suspended-core optofluidic photonic crystal fibers (PCF) for Raman spectroscopy to distinguish between saliva from healthy controls and OPMD patients. This novel approach provides enhanced Raman signals through prolonged interactions between the excitation light and the saliva sample along the length of the PCF. Raman spectra of liquid saliva samples were collected from eleven participants, including six OPMD patients and five healthy controls. Notable spectral differences were identified at 1123 cm⁻¹, 1251 cm⁻¹, and 1454 cm⁻¹, which correspond to carbohydrates, proteins, and lipids, respectively. In vivo tissue measurements were recorded as a reference for comparative analysis from the same patients. Our findings suggest that PCF-based Raman spectroscopy holds promise as a non-invasive diagnostic platform for oral cancer screening by enabling the monitoring of subtle molecular changes in liquid saliva.