Wirelessly Operated, Implantable Flexible Optoelectrical Probes for Optogenetics Neural Stimulation

Optogenetic methods with high temporal and spatial specificity have rapidly become a powerful technique in neuroscience. However, implantable fibers coupled with external laser sources as the traditional stimulated approach, constrain the free movement of experimental animals. In this study, we introduced a wireless-operated miniaturized implantable system with superior biocompatibility. The injectable dual-channel flexible neural probe with blue and orange light-emitting diodes (LEDs) was controlled using a customized circuit module powered by a rechargeable lithium battery. For excitatory and inhibitory neurons, the optical power densities of the blue and orange LEDs transferred to the flexible substrate can reach 25 and 18 mW/mm2, respectively, under an injection current of 5 mA. Moreover, the 2.4 GHz Bluetooth wireless communication protocol integrated into the circuit module enables LEDs to be remotely operated using mobile devices at a distance as far as 22.5 m. The movement traces of behaving animals after stimulation with optical signals can be recorded using an accelerometer and feedback to the terminal through Bluetooth chips. The proposed system provides an effective route for evaluating the functions and analyzing the structures of complicated animals.