Wireless deep-brain neuromodulation using photovoltaics in the second near-infrared spectrum

Conventional electrical neuromodulation techniques are constrained by the need for invasive implants in neural tissues, whereas methods using optogenetics are subjected to genetic alterations and hampered by the poor tissue penetration of visible light. Photovoltaic neuromodulation using light from the second near-infrared (NIR-II) spectrum, which minimizes scattering and enhances tissue penetration, shows promise as an alternative to existing neuromodulation technologies. NIR-II light has been used in deep-tissue imaging and in deep-brain photothermal neuromodulation via nanotransducers. This perspective provides an overview for the underpinning mechanisms of photovoltaic neuromodulation and identifies avenues for future research in materials science and bioengineering that can further advance NIR-II photovoltaic neuromodulation methods.