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ref: -0 tags: NET probes SU-8 microfabrication sewing machine carbon fiber electrode insertion mice histology 2p date: 12-29-2017 04:38 gmt revision:1 [0] [head]

PMID-28246640 Ultraflexible nanoelectronic probes form reliable, glial scar–free neural integration

  • SU-8 asymptotic H2O absorption is 3.3% in PBS -- quite a bit higher than I expected, and higher than PI.
  • Faced yield problems with contact litho at 2-3um trace/space.
  • Good recordings out to 4 months!
  • 3 minutes / probe insertion.
  • Fab:
    • Ni release layer, Su-8 2000.5. "excellent tensile strength" --
      • Tensile strength 60 MPa
      • Youngs modulus 2.0 GPa
      • Elongation at break 6.5%
      • Water absorption, per spec sheet, 0.65% (but not PBS)
    • 500nm dielectric; < 1% crosstalk; see figure S12.
    • Pt or Au rec sites, 10um x 20um or 30 x 30um.
    • FFC connector, with Si substrate remaining.
  • Used transgenic mice, YFP expressed in neurons.
  • CA glue used before metabond, followed by Kwik-sil silicone.
  • Neuron yield not so great -- they need to plate the electrodes down to acceptable impedance. (figure S5)
    • Measured impedance ~ 1M at 1khz.
  • Unclear if 50um x 1um is really that much worse than 10um x 1.5um.
  • Histology looks realyl great, (figure S10).
  • Manuscript did not mention (though the did at the poster) problems with electrode pull-out; they deal with it in the same way, application of ACSF.

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ref: -0 tags: Peter Ledochowitsch ECoG parylene fabrication MEMS date: 09-25-2014 16:54 gmt revision:0 [head]

IEEE-5734604 (pdf) Fabrication and testing of a large area, high density, parylene MEMS µECoG array

  • Details 5-layer platinum parylene process for high density ECoG arrays.

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ref: -0 tags: intracortical utah array fabrication MEMS Normann date: 08-14-2014 01:35 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-1937509 A silicon-based, three-dimensional neural interface: manufacturing processes for an intracortical electrode array.

  • Campbell PK1, Jones KE, Huber RJ, Horch KW, Normann RA. (1991)
  • One of (but not the) first papers describing their methods / idea (I think).
  • First conf paper: {1294} (1988)
  • later adopted glass frit insulator --

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ref: -0 tags: Seymour thesis electrode lithography fabrication date: 02-05-2012 17:35 gmt revision:4 [3] [2] [1] [0] [head]

Advanced polymer-based microfabricated neural probes using biologically driven designs.

  • References {1109}
  • Thermal noise from 280 um^2 or 170 um^2 gold recording sites much higher than PEDOT coated sites.
  • Used an interdigitated contact-free probe for measuring insulation impedance change. Very smart!
    • Water molecules will diffuse 15 um / minute in parylene (Yasuda, Yu et. al 2010).
    • In the frequency range critical for neural recording and stimulation, 500-5k, impedance moculus decline was small.
    • 1 hr soak at 60C.
  • Chapter 3 details 60-day soak of Parylene-C + reactive parylene insulation performance testing.
    • Regular parylene seems to work perfectly fine, no better than the PPX heat-treated devices.
    • Heat treatment does improve quality -- 200C in a vacuum oven for 2 days. (Li, Rodger et al 2005)
      • However -- this increases the brittleness.

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ref: Kennedy-1989.09 tags: Kennedy neurotrophic electrode recording fabrication 1989 electrophysiology date: 01-03-2012 03:21 gmt revision:2 [1] [0] [head]

PMID-2796391[0] The cone electrode: a long-term electrode that records from neurites grown onto its recording surface.

  • A piece of the sciatic nerve is placed in the glass cone before implantation in the cortex of a rat.
  • A neurite can be an axon or dendrite.

____References____

[0] Kennedy PR, The cone electrode: a long-term electrode that records from neurites grown onto its recording surface.J Neurosci Methods 29:3, 181-93 (1989 Sep)