Problems with bubbles in collagen gels - (Jun/09/2008 )

In my diploma work, I worked with thyroid follicle fragments cultured in a collagen sandwich which are supposed to reform to follicles.
But the method only work about once every third time since there are lots of cultures that can't be used in further experiments since the follicles quite often form monolayer sheet instead of keeping their 3D shape.

I've tried different seeding densities, collagen concentrations etc and the only thing that always occur and that seems to effect the shape in my cultures are BUBBLES and it seems to me that even if there is a tiny bubble in the edge of the gel, the whole culture may be ruined

I really try to be careful when neutralising the collagen solution and when mixing it with the cell suspension but I mean there have to be some mixing?
It is really frustration when making for example 24 gels in the wells of a 96-well plate and I'd be happy if I get 12 good cultures where there are none, or at least only a minority of fragments that form monolayer...

Anyone else with problems like this? Hopefully with some good advice?