title: Thermal and optical characterization of micro-LED probes for in vivo optogenetic neural stimulation.
abstract: Within optogenetics there is a need for compact light sources that are capable of delivering light with excellent spatial, temporal, and spectral resolution to deep brain structures. Here, we demonstrate a custom GaN-based LED probe for such applications and the electrical, optical, and thermal properties are analyzed. The output power density and emission spectrum were found to be suitable for stimulating channelrhodopsin-2, one of the most common light-sensitive proteins currently used in optogenetics. The LED device produced high light intensities, far in excess of those required to stimulate the light-sensitive proteins within the neurons. Thermal performance was also investigated, illustrating that a broad range of operating regimes in pulsed mode are accessible while keeping a minimum increase in temperature for the brain (0.5°C). This type of custom device represents a significant step forward for the optogenetics community, allowing multiple bright excitation sites along the length of a minimally invasive neural probe.
authors.affiliation: Institute of Photonics, SUPA, University of Strathclyde, Glasgow, UK. niall.mcalinden@strath.ac.uk
authors.forename: Niall
authors.initials: N
authors.lastname: McAlinden
authors.forename: David
authors.initials: D
authors.lastname: Massoubre
authors.forename: Elliot
authors.initials: E
authors.lastname: Richardson
authors.forename: Erdan
authors.initials: E
authors.lastname: Gu
authors.forename: Shuzo
authors.initials: S
authors.lastname: Sakata
authors.forename: Martin D
authors.initials: MD
authors.lastname: Dawson
authors.forename: Keith
authors.initials: K
authors.lastname: Mathieson
mesh_terms: D001921:Brain / Q000166:cytology; D004560:Electricity; D005708:Gallium; D055616:Microtechnology / Q000295:instrumentation*; D009474:Neurons / Q000166:cytology*; D055096:Optical Devices; D062308:Optogenetics / Q000295:instrumentation*; D013696:Temperature
chemical_list: C473348:gallium nitride; D005708:Gallium