Narrow-width surface acoustic wave device-driven olfactory epithelium-targeted intranasal atomization.

Intranasal administration offers a minimally invasive route for drug delivery to the brain by bypassing the blood-brain barrier compared to conventional intravenous and intrathecal administration. However, conventional intranasal delivery devices have difficulty accessing the entire olfactory epithelium region. This is because the olfactory epithelium is located deep in the upper nasal cavity. Therefore, the development of an atomization device capable of delivering aerosols across the whole olfactory epithelium is required to achieve direct access to the brain. Here, we propose an olfactory epithelium-targeted intranasal atomization system based on a narrow-width surface acoustic wave (NWSAW) device with directional atomization to the olfactory epithelium region. The NWSAW device with a width of 5 mm was fabricated for insertion through the external nostril. Compared with a nasal spray, the NWSAW device produced narrower atomization angles and smaller particles. Also, the NWSAW device with the longest busbar and the narrowest aperture width (LBNA) achieved atomization at lower input power. Moreover, an extended LBNA (Ex-LBNA) enabled deeper nasal insertion. Therefore, Ex-LBNA achieved atomization across the entire olfactory epithelium region, unlike the nasal spray and the LBNA. Notably, the immunoreactivity of insulin, a biopharmaceutical, was largely retained after the atomization process with the NWSAW device. These results indicate the potential of directional atomization using the NWSAW device for drug delivery to the brain.