An optogenetic system with high spatiotemporal resolution for brain-on-chips

Simultaneous optogenetic stimulation and electrophysiological recording of brain organoids required the development of a specialized optical system. This innovative system integrates a digital micromirror device (DMD) with a microelectrode array (MEA) to enhance interaction with the neural tissue. An ultra-high-power light-emitting diode (LED) with a central wavelength of 470 nm serves as the primary light source. Through a series of optical collimation and calibration steps, we successfully created high-resolution patterned projections on the surface of the brain organoid samples. The area of the projected image is 2.5×2.5 mm² . With a spatial resolution of 80 μm, the optical power intensity can reach 1.219 mW/mm² . Brain organoids were cultured on the MEA to facilitate the study of their responses. We investigated how different light stimulation modes influenced the neural network by detecting and recording extracellular field potentials at multiple sites within the network. This research provides valuable insights into the dynamics of brain organoids under optogenetic control.