I am making hydrogel beads with microfluidic droplet. The aqueous phase is a mixture of acrylamide, AA/bis-acrylamide, APS, and water.
The oil phase is fluoroOil and fluoroSufactant with 0.4% TEMED. I having be working fine with this formulation over a long time. What I did is to make droplet (water in oil), leave the droplets over night at 65C and release the polymerized gel beads. But the beads start to cluster since last week. They are chemically linked with each other (I flush the beads with all kinds of buffers, water, even HFE 7500 oil, they still clump together in the form of big cluster). In the very beginning, I thought it was because insufficient polymerization time (the whether got very cold recently), so I extended the incubation at 65C to 3 days. But still, the beads clustered after they are released from the droplets chemically. Can anyone please tell me any possible reasons why it happens? Or any other possible chemicals can lead to the clustering of the beads?
Much of gratitude for any help!
For reference only: It could be the result that you didn't add the right surfactant.
This is just my guess for I have no experience with it.
Kind regards,
Shuai
Has the supplier of chemicals changed? e.g. AA from different companies. Have you checked the pH of solution, is it same as before or has changed?
I found the reason. I though DEPC remnant in the water might be the cause of beads cross-linking since I made new buffers with MilliQ, beads stop crosslinking.
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