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{1382}
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ref: -0 tags: iridium oxide nanotube intracellular recording electroplate MEA date: 02-22-2017 22:41 gmt revision:0 [head]

PMID-24487777 Iridium oxide nanotube electrodes for sensitive and prolonged intracellular measurement of action potentials.

  • Electrodeposition of IrOx "magically" forms 500nm tubes.
  • Holes in Si3N4 / SiO2 were formed via e-beam lithography; underlying Pt wires via liftoff.
  • Showed long (minutes) intracellular access, though it tended to dip with time.

{1374}
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ref: -0 tags: nanoprobe transmembrane intracellular thiol gold AFM juxtacellular date: 02-06-2017 23:45 gmt revision:3 [2] [1] [0] [head]

PMID-20212151 Fusion of biomimetic stealth probes into lipid bilayer cores

  • Used e-beam evaporation of Cr/Au/Cr 10/10/10 or 10/5/10 onto a Si AFM tip.
    • Approx 200nm diameter; 1800 lipid interaction at the circumference.
  • Exposed the Au in the sandwich via FIB
  • Functionalized the Au with butanethiol or dodecanthiol; former is mobile on the surface, latter is polycrystaline.
    • Butanethiol showed higher adhesion to the synthetic membranes
  • Measured the penetration force & displacement through synthetic multi-layer lipid bilayers.
    • These were made via a custom protocol with 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) and cholesterol

PMID-21469728 '''Molecular Structure Influences the Stability of Membrane Penetrating Biointerfaces.

  • Surprisingly, hydrophobicity is found to be a secondary factor with monolayer crystallinity the major determinate of interface strength
  • Previous studies using ellipsometry and IR spectroscopy have shown that alkanethiol self-assembled monolayers display an abrupt transition from a fluid to a crystalline phase between hexanethiol and octanethiol.
    • This suggests the weakening of the membrane stealth probe interface is due to the crystallinity of the molecular surface with fluid, disordered monolayers promoting a high strength interface regime and rigid, crystalline SAMs forming weak interfaces.

{1377}
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ref: -0 tags: nanopore membrane nanostraws melosh surface adhesion intracellular date: 02-06-2017 23:34 gmt revision:0 [head]

PMID-22166016 Nanostraws for Direct Fluidic Intracellular Access

  1. Used track-etched polycarbonate membranes, which have controlled pore density & ID.
  2. Deposited alumina on the pores & external surfaces using ALD
  3. Then etched away the top alumina
  4. and finally used O2 RIE to etch away the polycarbonate.
  • Show that these nanopores have cytosolic access (via Fluor 488 - hydrazide membrane impermeant dye
  • Also used nanostraws to deliver Co+2 to quench GFP fluorescence.

PMID-24710350, Quantification of nanowire penetration into living cells.

  • We discover that penetration is a rare event: 7.1±2.7% of the nanostraws penetrate the cell to provide cytosolic access for an extended period for an average of 10.7±5.8 penetrations per cell.
  • Using time-resolved delivery, the kinetics of the first penetration event are shown to be adhesion dependent and coincident with recruitment of focal adhesion-associated proteins.
    • Hours for unmodified, 5 minutes for adhesion-promoting surface.
  • Chinese hamster oviary cells expressing GFP, Co+2 quenching, EDTA chelation.
  • To modulate cell adhesion, nanostraw substrates were incubated in 10 μg ml−1 fibronectin, a well-characterized cell adhesion molecule, in addition to the standard polyornithine coating.

{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...

{1368}
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ref: -0 tags: Leiber nanoFET review silicon neural recording intracellular date: 02-01-2017 03:32 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-23451719 Synthetic Nanoelectronic Probes for Biological Cells and Tissue

  • Review of nanowireFETS for biological sensing
  • Silicon nanowires can be grown via vapor-liquid-solid or vapor-solid-solid, 1D catalyzed growth, usually with a Au nanoparticle.
  • Interestingly, kinks can be introduced via "iterative control over nucleation and growth", 'allowing the synthesis of complex 2D and 3D structures akin to organic chemistry"
    • Doping can similarly be introduced in highly localized areas.
    • This bottom-up synthesis is adaptable to flexible and organic substrates.
  • Initial tests used polylysine patterning to encourage axonal and dendritic growth across a nanoFET.
    • Positively charged amino group interacts with negative surface charge phospholipid
    • Lieber's group coats their SU-8 electrodes in poly-d-lysine as well {1352}
  • Have tested multiple configurations of the nanowire FET, including kinked, one with a SiO2 nanopipette channel for integration with the cell membrane, and one where the cell-attached fluid membrane functions as the semiconductor; see figure 4.
    • Were able to show recordings as one of the electrodes was endovascularized.
  • It's not entirely clear how stable and scalable these are; Si and SiO2 gradually dissolve in physiological fluid, and no mention was made of longevity.

{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)