A wireless, implantable optoelectrochemical probe for optogenetic stimulation and dopamine detection

Abstract

Physical and chemical technologies have been continuously progressing advances of neuroscience research. The development of research tools for closed-loop control and monitoring neural activities in behaving animals is highly desirable. In this paper, we introduce a wirelessly operated, miniaturized microprobe system for optical interrogation and neurochemical sensing in the deep brain. Via epitaxial liftoff and transfer printing, microscale light emitting diodes (micro-LEDs) as light sources, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) coated diamond films as electrochemical sensors are vertically assembled to form implantable optoelectrochemical probes, for real-time optogenetic stimulation and dopamine detection capabilities. A customized, lightweight circuit module is employed for untethered, remote signal control and data acquisition. Injected into the ventral tegmental area (VTA) of freely behaving mice, in vivo experiments clearly demonstrate the utilities of the multifunctional optoelectrochemical microprobe system for optogenetic interference of place preferences and detection of dopamine release. The presented options for material and device integrations provide a practical route to simultaneous optical control and electrochemical sensing of complex nervous systems.

A wireless optoelectronic probe to monitor oxygenation in deep brain tissue

“…Meanwhile, the combination of electrophysiological activities, PbtO2 and blood oxygenations will foster a more profound understanding of the neurovascular and neurometabolic coupling 64,65 . In the future, the PbtO2 probe can integrate with other microscale devices for detecting electrophysiological signals 66 , calcium fluorescence 67,68 , neurotransmitters 69,70 and temperature 71,72 , to realize multi-modal neural sensing. Additionally, the PbtO2 sensing technique can collaborate with optogenetic and non-genetic stimulations 73,74 , to achieve closed-loop interrogation.…”

Flexible optoelectric neural interfaces

“…To address the size and density limitations, smaller LED chips have been custom-designed and fabricated. In this method, first, an array of micro-LEDs are fabricated on a sapphire substrate and the flexible probe shanks are fabricated on a separate substrate and then the micro-LEDs with dimensions as small as 50 μm × 50 μm × 6.45 μm are transferred to the polymer substrate using a laser liftoff (LLO) process, where an excimer laser is used to detach GaN from sapphire [ 67 , 68 , 69 •• ]. The flip-chip bonding process requires precise alignment and is usually serial, which would limit the scalability and throughput of the packaging process.…”