The potential of nano-enabled oral ecosystem surveillance for respiratory disease management

The association between oral disorders and respiratory diseases has been revealed for decades. Emerging oral biomarkers, including microbiome, metabolites, proteins, and nucleic acids, have been gradually discovered and proposed to contribute to the development and progression of both oral and respiratory diseases. While promising, oral ecosystem surveillance remains confined due to the constant changes in the oral ecosystem and the lack of sophisticated assessment technologies. With the advent of nanotechnology, efficient diagnostics and real-time monitoring of disease are implemented via platforms such as biomarker-capturing nanoparticles, nanobiosensors, nano-microfluidics, and wearable devices. In this review, the association between the oral ecosystem and respiratory system, especially the clinical relevance and cross-regulatory mechanisms, will be first discussed. Saliva, serving as a readily available biofluid for non-invasive diagnostics, will be overviewed for the emerging biomarkers in respiratory disease diagnosis. The latest nanotechnology-enabled approaches will be highlighted in terms of oral biomarker enrichment, multiplexing analysis, sensitive and selective diagnosis, and nanodentistry. Finally, the incorporation of nano-enabled approaches into routine clinical practice will be prospected for future translation.