I had previously made my own plasma cleaner using a pump and an old microwave. While my homemade version technically worked, it was complicated to use, unwieldily, and inconsistent in performance. In fact, at least one test made my glass coverslips dirtier.
So we purchased a Harrick plasma cleaner. I’ve used these in the past for preparing coverslips for single-molecule imaging as well treating coverslips before forming supported lipid bilayers on the glass. I’ve always found plasma treatment to be simpler and more consistent that chemical methods such as piranha.
You can see a lot of single-molecule level fluorescent impurities on the glass surface before cleaning (these are a few frames stitched together):
And after 4 minutes of plasma treatment (with air as the process gas) it was so clean that I had trouble finding the correct focal plane:
People are also using this plasma cleaner to treat material for PDMS bonding to glass. They say it’s been working very consistently.
So I highly recommend plasma cleaning. It takes literally a few minutes and there’s no hazardous waste to dispose of. The only real drawback is the price: a new cleaner plus pump costs several thousand dollars. In the long run, if we can get consistent science and no haz waste disposal costs, that price will be worth it. (We also split the cost with several other labs on our floor.)
I’ve also heard good things about ozone treatment. Anyone have any comments about ozone vs plasma?
- Very easy to use
- Fast (<5 min) cleaning
- Updated models of Harrick cleaners have a nice hinged door
- Using process gases other than simply air (such as argon) is slightly more complicated, because you’ll need a tank and tubing; oxygen plasma cleaning requires a more expensive pump