Salivary exosomes: emerging diagnostic modalities for cancer, brain and immunological disorders

INTRODUCTION: Cancer, brain and immunological disorders are among the main causes of illness and death all over the world, involving complex changes at the molecular and cellular level. Conventional methods of diagnosis may have limited sensitivity when it comes to detecting molecular changes, thus there is a need for strategies that are noninvasive and have better analytical accuracy. Salivary exosomes are nanosized extracellular vesicles that contain a variety of bioactive molecules, with their lipid bilayer protecting cargo from enzymatic degradation. AREAS COVERED: The review covers the biogenesis, secretion, systemic dynamics, molecular cargo, and diagnostic potential of salivary exosomes in cancer, brain, and immunological disorders. Multi-omics approaches and database-driven resources for molecular characterization and biomarker discovery are discussed. Nanotechnology-based platforms for exosome isolation, enrichment, characterization are also covered, emphasizing their role in sensitive molecular analysis and noninvasive diagnosis. EXPERT OPINION: Salivary exosomes contain diverse molecular information that has diagnostic potential. Saliva is easily accessible to perform minimally invasive molecular analysis but isolation, characterization and analytical procedures vary, so reproducibility can be impaired. Standardized methodologies and validation are needed to establish diagnostic relevance and evidence for salivary exosome-based diagnostics.