Steve,
	We have done some similar work in the past and found that using
methacrylate or LR white resin to embed the discs solved the problem and
enhanced resolution of the cultured cells. You can also still cut sections
from the resin blocks using steel knives although I would accept that it is
easier with glass knives.
	Regards,
	          Tony Savage

	

> -----Original Message-----
> From:	Steve Machin UK [SMTP:stevemachinuk@yahoo.co.uk]
> Sent:	Sunday, May 12, 2002 7:38 PM
> To:	Histonet Histonet Histonet
> Subject:	silicone membrane sections
> 
> I have had a request to cut sections from a novel porous silicone
> discs onto which is grown ciliated epithelium.
> The silicone membrane is made buy mixing a silicone plastic with fine
> salt grains and extruding the mixture through a circular dye to form
> cylinders.
> These cylinders are cut into circular discs.
> The discs are washed in water to remove the salt which leaves an open
> mesh network of the plastic.
> Fibroblasts are grown on the discs and then ciliated epithelium is
> grown on the fibroblasts.
> The object is to cut sections to see the penetration of cells into
> the open structure of the disc.
> I have tried processing into wax but the plastic is too soft and it
> pulls away from the wax.
> Soaking the disc in gelatine and fixing before processing does not
> help either because the plastic remains flexible.
> I have tried frozen sections but again the plastic remains flexible
> at -20C and will not section.When looking at the sections down the
> microscope is is clear that the plastic is pulling away from the wax.
> Freezing in liquid nitrogen makes the discs stiff but we don't have a
> cryostat which will get down to those temperatures.
> Does anyone know of a way to harden the plastic without artifactually
> damaging the cells grown upon it?
> I would love to here from workers who have solved this problem.
> 
> Best Wishes
> 
> Steve Machin
> Sheffield Children's Hospital UK
> 
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