I've recently seen a paper that utilises a thermo-reversible hydrogel mountant technology (CyGEL(tm)) to permit time-lapse imaging of live imaging of developing embryos over 5-day periods!
The hydrogel sets stiff enough to hold the embryo without inhibiting development. The Singapore lab of Dr Martin Wasser (A*STAR) created a humidified chamber for the hydrogel using a moistened tissue, which was simple yet sufficient for their purposes, allowing them to follow muscle development / remodelling in real-time.
This is not their first publication citing CyGEL but is the first to refer to its use over such long timeframes.
The citation is:
Kuleesha, Yadav, Wee Choo Puah, and Martin Wasser. "A model of muscle atrophy based on live microscopy of muscle remodelling in Drosophila metamorphosis." Royal Society Open Science 3.2 (2016): 150517.
Available as open access, here:
By way of background, CyGEL was originally developed some years back for non-adherent cells but has seen most use in immobilisation of live embryos (incl Danio), C. elegans and fragile objects like micro-tissues, tumor spheroids and excised mosquito gut - many of which I've had a go at myself. That's also included some work with live Drosophila embryos to image NMJs and boutons - imaging as long as possible between muscle spasms that are like explosions!
I've also made more "sophisticated" humidified chambers using coverglass-bottomed petri-dishes. The "well" for the hydrogel mountant is created with a silicone grease-smeared o-ring, then surrounded with LMP Agarose as the humidification medium and organisms and CyGEL placed in the central well.
Usefully, because CyGEL is thermo-reversible, it can be "melted" or liquefied by cooling below room temperature to permit repositioning or ultimately for non-destructive recovery of intact live objects/organisms for orthogonal analysis or onward growth.
You can read a couple of independent product reviews here:
A brief review article was published back in 2010 which gives an overview:
Full technical data, key references, etc. can be found here: