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{1375}
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ref: -0 tags: intracellular juxtacellular recording tungsten nanowire whole cell patch date: 02-06-2017 22:39 gmt revision:2 [1] [0] [head]

PMID-22905231 Neuronal recordings with solid-conductor intracellular nanoelectrodes (SCINEs).

  • <300 nm diameter W fibers, several um long, fabricated via FIB.
  • Functionalized with a hydrophobic silane on the oxide.
    • Quite complete & custom methods here.
  • Not quite whole cell recording, but excellent SNR; 4mv APs.
    • Slice, rat hippocampus organotypic.
    • Expected much larger recorded APs; suspect partial membrane penetration.
    • Only lasted a few seconds to minutes.
  • Needed custom recording setup for interfacing with 100Gohm electrodes; stray capacitance < 4 pf.
  • Intracellular electrodes must be designed to not shunt the membrane open upon insertion.
    • In a study where whole-cell recordings were established prior sharp microelectrode penetration, all neurons showed significant depolarization following impalement.
    • Here there was no change in membrane voltage in 10% of insertions of the silane-functionalized SCINEs. only in the functionalized electrodes).
    • Minor distortion of the AP was observed.
  • In whole-cell patch clamping, diffusion from the pipette to the cytosol interrupts biochemical processes necessary for normal cellular function (e.g. respiration!).
  • The hardness of the tungsten ensures that SCINEs can be repeatedly inserted millimeter-deep into brain tissue without noticeable damage to the tip.
    • E.g. 300 nm tungsten will not easily navigate vasculature...

{1369}
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ref: -0 tags: vertical nanowire juxtacellular recording date: 02-01-2017 00:50 gmt revision:2 [1] [0] [head]

PMID-22231664 Vertical nanowire electrode arrays as a scalable platform for intracellular interfacing to neuronal circuits.

  • Note actual coupling is low, 0.002, compared to patch-clamp (400uV vs 200mV). Signal is rather noisy.
  • Dissociated cultures of rat cortical neurons
  • Stimulation current 200 pa enough to change membrane potential, but not initiate a spike.
    • This is 200e-12 / 20e-6 = 5 orders of magnitude lower current than typical ICMS.

{1327}
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ref: -0 tags: ice charles lieber silicon nanowire probes su-8 microwire extracellular date: 10-14-2016 23:28 gmt revision:2 [1] [0] [head]

PMID-26436341 Three-dimensional macroporous nanoelectronic networks as minimally invasive brain probes.

  • Xie C1, Liu J1, Fu TM1, Dai X1, Zhou W1, Lieber CM1,2.
  • Again, use silicon nanowire transistors as sensing elements. These seem rather good; can increase the signal, and do not suffer from shunt resistance / capacitance like wires.
    • They're getting a lot of mileage out of the technology; initial pub back in 2006.
  • Su-8, Cr/Pd/Cr (stress elements) and Cr/Au/Cr (conductor) spontaneously rolled into a ball, then the froze in LN2. Devices seemed robust to freezing in LN2.
  • 300-500nm Su-8 passivation layers, as with the syringe injectable electrodes.
  • 3um trace / 7um insulation (better than us!)
  • Used 100nm Ni release layer; thin / stiff enough Su-8 with rigid Si support chip permitted wirebonding a connector (!!)
    • Might want to use this as well for our electrodes -- of course, then we'd have to use the dicing saw, and free-etch away a Ni (or Al?) polyimide adhesion layer -- or use Su-8 like them. See figure S-4
  • See also {1352}

{1243}
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ref: -0 tags: polyimide platinum nanowire recording electrode plating date: 06-28-2013 00:46 gmt revision:2 [1] [0] [head]

IEEE-5734597 (pdf) A novel platinum nanowire-coated neural electrode and its electrochemical and biological characterization

  • Young-Hyun Jin ; IMTEK, Univ. of Freiburg, Freiburg, Germany ; Daubinger, P. ; Fiebich, B.L. ; Stieglitz, T.
  • 10um thick RIE etched polyimide and platinum electrodes.
  • polyimide was spin coated onto wafers.
  • Used relatively simple wet chemistry to plate platinum onto electrodes:
    • 0.14 M-% chloroplatin acid hexahydrate (H2PtCl6ยท6H2O, Sigma-Aldrich) and 7.4 M-% formic acid (HCOOH, Sigma-Aldrich) were mixed in de-ionized (DI) water. The fabricated device was floated upside down on the solution.
  • Let this plate for 7 days & effective site was enlarged by 617 times!

{841}
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ref: Tian-2010.08 tags: nanowire nanoprobe silicon FET doping cis trans extracellular intracellular recording neuro MEA date: 01-03-2012 16:35 gmt revision:4 [3] [2] [1] [0] [head]

PMID-20705858[0] Three-Dimensional, Flexible Nanoscale Field-Effect Transistors as Localized Bioprobes

  • Made a silicon nanowire with 60 deg. kinks via trans/cis manipulation.
  • Doped one part of the N nanowire P to make a 200nm long FET whose gate is simply the surface of the nanowire (I think, have to check the refs)
  • Attached the nanoprobe / nanowire to flexible PMMA / SM-8 support which, due to interfacial stress, rose off the substrate (clever!)
  • Coated tip with phospholipid layers -> better cell attachment / penetration.
    • Possible to have the cell pull the nanoprobe in via endocytic pathways.
  • Were able to record intracellular and extracellular AP from rabbit cardiocytes. (!!!)

____References____

[0] Tian B, Cohen-Karni T, Qing Q, Duan X, Xie P, Lieber CM, Three-dimensional, flexible nanoscale field-effect transistors as localized bioprobes.Science 329:5993, 830-4 (2010 Aug 13)