PMID- 32365472
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20200928
IS  - 2072-666X (Print)
IS  - 2072-666X (Electronic)
IS  - 2072-666X (Linking)
VI  - 11
IP  - 5
DP  - 2020 Apr 29
TI  - Fabrication of Subretinal 3D Microelectrodes with Hexagonal Arrangement.
LID - 10.3390/mi11050467 [doi]
LID - 467
AB  - This study presents the fabrication of three-dimensional (3D) microelectrodes for 
      subretinal stimulation, to accommodate adjacent return electrodes surrounding a 
      stimulating electrode. For retinal prosthetic devices, the arrangement of return 
      electrodes, the electrode size and spacing should be considered together, to 
      reduce the undesired dissipation of electric currents. Here, we applied the 
      hexagonal arrangement to the microelectrode array for the localized activation of 
      retinal cells and better visual acuity. To provide stimuli more efficiently to 
      non-spiking neurons, a 3D structure was created through a customized pressing 
      process, utilizing the elastic property of the materials used in the fabrication 
      processes. The diameter and pitch of the Pt-coated electrodes were 150 mum and 350 
      mum, respectively, and the height of the protruded electrodes was around 20 mum. 
      The array consisted of 98 hexagonally arranged electrodes, supported by a 
      flexible and transparent polydimethylsiloxane (PDMS) base, with a thickness of 
      140 mum. Also, the array was coated with 2 mum-thick parylene-C, except the active 
      electrode sites, for more focused stimulation. Finally, the electrochemical 
      properties of the fabricated microelectrodes were characterized, resulting in the 
      mean impedance of 384.87 kOmega at 1 kHz and the charge storage capacity (CSC) of 
      2.83 mC.cm(-2). The fabricated microelectrodes are to be combined with an 
      integrated circuit (IC) for additional in vitro and in vivo experiments.
FAU - Seo, Hee Won
AU  - Seo HW
AUID- ORCID: 0000-0003-0646-9806
AD  - Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and 
      Technology (DGIST), Daegu 42988, Korea.
FAU - Kim, Namju
AU  - Kim N
AD  - Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and 
      Technology (DGIST), Daegu 42988, Korea.
FAU - Kim, Sohee
AU  - Kim S
AUID- ORCID: 0000-0002-4926-8978
AD  - Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and 
      Technology (DGIST), Daegu 42988, Korea.
LA  - eng
GR  - NRF-2017M3A9E2056463/National Research Foundation of Korea/
PT  - Journal Article
DEP - 20200429
PL  - Switzerland
TA  - Micromachines (Basel)
JT  - Micromachines
JID - 101640903
PMC - PMC7281732
OTO - NOTNLM
OT  - 3D electrodes
OT  - hexagonal electrodes
OT  - retinal implant
OT  - subretinal stimulation
OT  - transparent base
COIS- The authors declare no conflict of interest.
EDAT- 2020/05/06 06:00
MHDA- 2020/05/06 06:01
PMCR- 2020/04/29
CRDT- 2020/05/06 06:00
PHST- 2020/03/29 00:00 [received]
PHST- 2020/04/26 00:00 [revised]
PHST- 2020/04/27 00:00 [accepted]
PHST- 2020/05/06 06:00 [entrez]
PHST- 2020/05/06 06:00 [pubmed]
PHST- 2020/05/06 06:01 [medline]
PHST- 2020/04/29 00:00 [pmc-release]
AID - mi11050467 [pii]
AID - micromachines-11-00467 [pii]
AID - 10.3390/mi11050467 [doi]
PST - epublish
SO  - Micromachines (Basel). 2020 Apr 29;11(5):467. doi: 10.3390/mi11050467.