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This video shows how to fill one well of a 4-well ibidi with Glox and then seal the top with a coverslip so there are no air bubbles (and hence no oxygen ingress). It is also possible to seal the chamber by inverting the lid of the ibidi chamber and sliding that over the wells. In that way all the wells can be sealed.
In the image below I have sealed the middle two wells by sliding the inverted lid across them.
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