3D-printed Optogenetic Stimulator Integrated with a Recording Channel

This paper presents the design, fabrication, and validation of an optogenetic stimulator with a neural signal recording electrode. While most optogenetic devices have been mainly fabricated using microfabrication techniques, we utilized 3D printing technologies that have the unique capability of two-photon polymerization (2PP). This allows us to print micrometer-sized complex 3D features with a high level of precision and accuracy. The device incorporates a micro-sized light-emitting diode $(\mu$ LED) and $50-\mu\mathrm{m}$-diameter wires with solder balls for electrical connections. It also includes a neural recording channel using an additional wire embedded on the device, enabling neural signal monitoring during the neural modulation process. The results of electrical and optical property tests for validation of device functionality are also presented. Additionally, the measured impedance results of the recording channel verify the device’s feasibility for recording biosignals. Overall, our results demonstrate the successful development of an optogenetic device with a neural signal recording electrode, which has the potential to advance the field of neural modulation.