Advancing Obstructive Sleep Apnea Therapy: a Miniaturized Wireless Implant for Battery-Free Optogenetic Neurostimulation in Mice

Obstructive sleep apnea is a chronic respiratory condition characterized by frequent episodes of upper airway collapse during sleep, often leading to cognitive and cardiovascular dysfunctionalities. While continuous positive airway pressure remains the standard treatment, its effectiveness is compromised by low adherence rates. Optogenetic neurostimulation of the hypoglossal neural nuclei represents a promising breakthrough in the field, offering a non-invasive alternative, which leverages light-sensitive receptors for precise neuronal activation. This work presents a novel wireless power transfer system to enable battery-free optogenetic stimulation for treating this pathological condition in laboratory mice. Operating at 13.56 MHz, the wireless power transfer system features a conformal transmitting array and a miniaturized implantable receiving device designed for enhanced misalignment tolerance and uniform power delivery. The system supplies a microscale light emitting diode targeting the hypoglossal nuclei, ensuring continuous light delivery regardless of the mouse’s positioning. Experimental results demonstrate reliable performance even under worst-case alignment scenarios, with a measured rectified power of 14.7 mW, which meets the µ-LED operational requirements for guaranteeing the radiant flux desired for successful neurostimulation.