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{1406}
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ref: -0 tags: insertion speed needle neural electrodes force damage injury cassanova date: 06-01-2018 23:51 gmt revision:0 [head]

Effect of Needle Insertion Speed on Tissue Injury, Stress, and Backflow Distribution for Convection-Enhanced Delivery in the Rat Brain

  • Tissue damage, evaluated as the size of the hole left by the needle after retraction, bleeding, and tissue fracturing, was found to increase for increasing insertion speeds and was higher within white matter regions.
    • A statistically significant difference in hole areas with respect to insertion speed was found.
  • While there are no previous needle insertion speed studies with which to directly compare, previous electrode insertion studies have noted greater brain surface dimpling and insertion forces with increasing insertion speed [43–45]. These higher deformation and force measures may indicate greater brain tissue damage which is in agreement with the present study.
  • There are also studies which have found that fast insertion of sharp tip electrodes produced less blood vessel rupture and bleeding [28,29].
    • These differences in rate dependent damage may be due to differences in tip geometry (diameter and tip) or tissue region, since these electrode studies focus mainly on the cortex [28,29].
    • In the present study, hole measurements were small in the cortex, and no substantial bleeding was observed in the cortex except when it was produced during dura mater removal.
    • Any hemorrhage was observed primarily in white matter regions of the external capsule and the CPu.

{1286}
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ref: -0 tags: ovipositor wasp fig needle insertion SEM date: 05-29-2014 19:58 gmt revision:0 [head]

Biomechanics of substrate boring by fig wasps

  • Lakshminath Kundanati and Namrata Gundiah 2014

{1162}
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ref: -0 tags: polymide flexible electrode Rousche incision needle assist date: 01-30-2013 06:38 gmt revision:3 [2] [1] [0] [head]

PMID-11327505 Flexible Polyimide-Based Intracortical Electrode Arrays with Bioactive Capability

  • Use gold / polymide fabrication; electrode is 20um thick, 160um wide.
  • Still quite flexible -- buckles at 0.003 N.
  • Successfully recorded by inserting it in an incision in rat barrel cortex -- needle assist.
    • Well, not too successfully.
  • Suggest that bioactive components can be applied to the permeable polymide surface.

____References____

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{1178}
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ref: -0 tags: parylene flexible neural recording drug delivery microfluidics 2012 inserter needle release date: 01-02-2013 22:41 gmt revision:1 [0] [head]

PMID-23160191 Novel flexible Parylene neural probe with 3D sheath structure for enhancing tissue integration

  • They seem to think that drugs are critical for success: "These features will enhance tissue integration and improve recording quality towards realizing reliable chronic neural interfaces."
  • Similar to Kennedy: "The sheath structure allows for ingrowth of neural processes leading to improved tissue/probe integration post implantation." 8 electrodes, 4 on the cone interior, 4 on the exterior.
    • opening is 50um at tip, 300 um at base.
  • Used a PEEK-stiffened parylene ZIF connection.
  • Only tested in agarose, but it did properly release from the inserter needle.
  • I wonder if we could use a similar technique..
  • "Lab on a chip" journal (Royal society of Chemistry). nice.