Labs I've known doing working with similar thermoresponsive hydrogels have used a couple approaches to storage, both of which seem valid to me:

1) You can simply store the microspheres at -20 C, like this group did: Article Synthesis and Characterization of Thermoresponsive Hydrogels...

2) For better long-term storage, you can freeze-dry them, like this group did:

https://www.nature.com/articles/am201583 . Though I don't have personal experience with this myself (I have a background working with nanoparticles and polymer-drug conjugates), I believe you're supposed to recover them by re-swelling.

Shwan Javdan

Thank you so much sir for these helpful information.

It will helps me a lot.

Regards

Rana