Hi Marcela. We're installing the light microscope in our 120cm hood after thoroughly spraying and wiping with 70% ethanol (avoid spraying on the electric ports at all costs) and close the window just enough to get an uninterrupted flow. Do the same for the power adapter and its cord, as some of its parts will probably need to be put inside the hood.

Then we spot the colonies and cut it into ~50micron pieces using either p10 or p100 pipette tip or a sterile needle. Stabilizing hands as much as you can is the most important trick here. Also, if a needle is preferred for cutting, you need to be careful not to scrape the plastic from the plate as it will probably stick to colony pieces and come along to the fresh plate and may prevent the colony pieces to properly attach, being gentle when using the needle is essential.

It is quite easy to work with a 6 and 12-well plate. But smaller wells like 24 or 48 are terribly hard to perform an ideal colony dissection.

To begin with, I strongly recommend focusing on colonies from the edges of the well as they are much easier to access and dissect, colonies in the middle part are a bit trickier depending on the shape of your microscope. We've never had a hard time by solely sticking to the ultimate hPSC colony morphology when selecting clones of primary hiPSCs, though some labs prefer pre-staining with alkaline phosphatase just to be safe.