The Artificial Synapse Chip: a flexible retinal interface based on directed retinal cell growth and neurotransmitter stimulation.
The Artificial Synapse Chip is an evolving design for a flexible retinal interface that aims to improve visual resolution of an electronic retinal prosthesis by addressing cells individually and mimicking the physiological stimulation achieved in synaptic transmission. We describe three novel approaches employed in the development of the Artificial Synapse Chip: (i) micropatterned substrates to direct retinal cell neurite growth to individual stimulation sites; (ii) a prototype retinal interface based on localized neurotransmitter delivery; and (iii) the use of soft materials to fabricate these devices. By patterning the growth of cells to individual stimulation sites, we can improve the selectivity of stimulation and decrease the associated power requirements. Moreover, we have microfabricated a neurotransmitter delivery system based on a 5- micro m aperture in a 500-nm-thick silicon nitride membrane overlying a microfluidic channel. This device can release neurotransmitter volumes as small as 2 pL, demonstrating the possibility of chemical-based prostheses. Finally, we have fabricated and implanted an equivalent device using soft flexible materials that conform to the retinal tissue more effectively. As many of the current retinal prosthesis devices use hard materials and electrical excitation at a lower resolution, our approach may provide more physiologic retinal stimulation.
Peterman
Mark C
MC
Department of Applied Physics, Stanford University, Stanford University, Stanford, CA, USA.
Mehenti
Neville Z
NZ
Bilbao
Kalayaan V
KV
Lee
Christina J
CJ
Leng
Theodore
T
Noolandi
Jaan
J
Bent
Stacey F
SF
Blumenkranz
Mark S
MS
Fishman
Harvey A
HA
D000818:Animals; D001920:Bradykinin / Q000008:administration & dosage*; D004129:Dimethylpolysiloxanes; D016503:Drug Delivery Systems; D004558:Electric Stimulation / Q000295:instrumentation; D009757:Nylons; D016716:PC12 Cells; D019736:Prostheses and Implants; D011474:Prosthesis Design; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D012165:Retinal Ganglion Cells
D004129:Dimethylpolysiloxanes; D009757:Nylons; C085707:poly(dimethylsiloxane)-polyamide copolymer; D001920:Bradykinin