Implantable micro and nanophotonic devices: toward a new generation of neural interfaces

This review focuses on the role that micro and nanotechnologies are having in the development of a new generation of optical neural interfaces for deep brain regions. The advent of optical methods to control and monitor neural activity has indeed raised neuroscientists’ demand for small, soft and multifunctional devices to interface with sub-cortical structures. These are indeed widely inaccessible with microscopy-based approaches, and the scientific community has proposed complementary methods based on integrated photonics, implantable micro LEDs and engineered optical fibers. After discussing advantages and drawbacks of these methods, the manuscript closes with an overview on the emerging field of optical neural interfaces based on colloidal nanoparticles. [Display omitted] •Micro and nanotechnologies are a key for next generation of optical neural interfaces.•Integrated photonics is one of the main roads to realize fully integrated devices.•Implantable μLEDs allow for wireless optical stimulation of neural activity.•Engineered optical fibers reach sub-cortical structures with reduced invasiveness.•Nanoparticles bring quantum confinement and light-matter interactions in the brain.