Prof. Long-Sheng Fan
National Tsing Hua University/UC Berkeley
April 5, 2011 | 12:00 to 01:00 | 540 Cory Hall, DOP Center Conference Room
Host: John Huggins
To achieve localized retinal neural stimulation with high granularity over reasonable field of view within power constraints, we integrated a flexible 4,096-element retina chip 30 um in total thickness including passivation layers using a flexible 180nm CMOS Image Sensor (CIS) technology. The retina chip is 3x3 mm in size (including multiplexing electronics for pixel characterizations) with an array of 10um electrodes and photo sensors 30um in pitch. The flexible format allows better proximity between electrodes and retina neurons for localized stimulation, and the integrated local electronics allows supplying individual electrode the adequate and appropriate stimulation waveforms right next to each individual electrodes. The chip senses local light intensity and generates corresponding biphasic current at each pixel. Images are projected onto the chip and corresponding biphasic currents for stimulating retina tissue from each pixel are mapped through DAQ hardware & software. Loose patch and whole-cell patch clamp techniques in vitro are used to characterize the NZ white rabbit and mouse retinal ganglion cells responses on these arrays with bipolar cells side facing toward the electrode array. With local active devices and signal processing capability, it could also potentially be an enabling tool to interface retinal neurons to the individual cell level for studying retinal neural network.
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