Dear all,
our lab routinely performs in vivo recordings in awake behaving head-fixde mice using silicon multichannel micro-electrode arrays. These silicon probes are repeatedly inserted into and withdrawn from the brain during multiple sessions. Between sessions, craniotomy windows are covered using Kwik-cast silicon sealant applied into a well of dental cement, and electrodes as cleaned using Tergazyme and repeated washes of ethanol and distilled water. There have been discussions in the lab on how to maintain the dura in as healthy a state as possible and I would be glad to hear your opinion on some of the points raised:
Long exposure of the dura to air may cause it to become dry and hard, which is also problematic for the insertion of fragile silicon probes. So it seems natural to apply saline, even just to the craniotomy rather than the entire dental cement well. However, some colleagues think that saline may carry bacteria from other parts of the dental cement well into the craniotomy and increase the risk of an infection. Moreover, they think that keeping the dura wet and soft may make it more susceptible to being penetrated by bacteria. On the other hand, it does not seem sensible to keep dura in an unnatural dried-up state, so ideally, one would want to keep it wet while minimising the risk of an infection. I have heard that some researchers apply the antibiotic Baytril directly onto the dura for that purpose. However, one quick google search has shown that fluoroquinolones (like Baytril) are competitive GABA-antagonists (see link), which would be a concern.
I would be happy to hear your suggestions!
Many thanks,
Yannik
http://buybaytril.com/baytrilfaq.html
I have no personal experience with this chemical, but I was told that 5-fluorouracil can do wonderful things for chronic recording preps.
Spinks et al. (2003) Problem of dural scarring in recording from awake, behaving monkeys: a solution using 5-fluorouracil. J Neurophysiol 90(2) 1324-1332. DOI: 10.1152/jn.00169.2003
I do agree with Jun, fluorouracil works nicely for chronic implants. I have tried it on monkeys and works perfectly fine, however you need to flush quite often.
Other people have used special silicon to cover the entri points. However, it all depends about the size of your trepanation and the size of your durotomy!
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