Unraveling olfactory mucus mysteries with microfluidics and humanized yeast biosensors

Olfactory sensory neurons are vital for detecting odorants, present within the intricate matrix of olfactory mucus. Composed mostly of water (90%), with mucin, proteins, salts, carbohydrates, and lipids, olfactory mucus acts as both a protective barrier and a conduit for aroma compounds. Despite its crucial role, the influence of olfactory mucus on sensory receptors and aroma compound diffusion remains poorly understood. Lab-on-chip technology offers a promising platform for this investigation. We aim to use a microfluidic model with a single-cell yeast layer and simulated mucus environment to investigate this influence. We are engineering yeast to express several human sensory olfactory receptors, including OR17-40, well-known for helional detection (floral scent). Utilizing the yeast MAPK biosensor chassis, our engineered yeast biosensor will emit fluorescence signals upon activation. These humanized olfactory yeast cells will then be integrated into an advanced two-phase microfluidic model, creating an "artificial nose" for odorant detection. We are exploring different polymers for the fabrication of the microfluidic device and optimizing the channel design. Currently, we are conducting yeast biocompatibility assays with the selected polymers, while simultaneously optimizing methodologies to immobilize yeast cells onto the surface of the microchannels. Additionally, we are optimizing the composition of the simulated mucus and determining the optimal flow rates necessary within the microfluidic chamber to promote optimal aroma compound diffusion rates. This model will facilitate exploring the impact of genetic variations in sensory receptors and mucus composition on the diffusion and binding of aroma compounds to the receptors, advancing our understanding of olfactory mechanisms.