Nanophotonics: A Nascent Tool in Early Detection of Oral Cancer Using Saliva-Based Diagnostics

Abstract

Oral squamous cell carcinoma (OSCC) stands as the sixth most prevalent malignancy globally among both sexes, with a concerning survival rate of approximately 5% over five years. The persistently high mortality rate is primarily due to the delayed diagnosis, often at advanced and less treatable stages. Early detection remains a cornerstone for improving patient prognosis and survival outcomes. In this context, there is a growing need for highly specific, sensitive, and non-invasive diagnostic tools. Nanophotonics has recently emerged as a promising imaging and diagnostic modality with the potential to revolutionize early cancer detection. Saliva, as a diagnostic biofluid, offers several advantages over traditional invasive techniques. It is readily accessible, non-invasive, and capable of reflecting systemic physiological and pathological conditions. A wide array of cancer biomarkers, including proteins, nucleic acids, and metabolites, can be reliably measured in saliva. Among these, the epidermal growth factor receptor (EGFR) has been recognized as a significant biomarker in OSCC due to its overexpression in malignant oral tissues. Nanophotonics leverages the interaction between light and nanomaterials to enhance the sensitivity of diagnostics. In the case of oral cancer detection, nanophotonic platforms utilize antibody-conjugated gold nanoparticles specifically designed to bind to EGFR present in saliva. When combined with surface-enhanced Raman scattering (SERS) — a powerful optical technique that amplifies molecular vibrational signals — these nanoparticles provide a highly sensitive and specific method for biomarker detection. Raman spectroscopy, facilitated by nanophotonic enhancement, enables the detection of even trace amounts of EGFR, facilitating the identification of malignancy at its inception. This paper explores the cutting-edge applications of nanophotonic in salivary diagnostics, particularly focusing on the synergy of gold nanoparticle-based biosensing and SERS in identifying EGFR. The integration of nanotechnology with optical science paves the way for a transformative approach in the early detection of oral cancer, offering a non-invasive, rapid, and accurate diagnostic alternative. As the “war with cancer” continues, such nascent technologies hold immense potential in shifting the clinical paradigm toward earlier intervention and improved survival rates.