# What would it take to build a molecular machine to separate isotopes? # What would it take to build a molecular machine to separate isotopes Normally, isotopes are separated stochastically - What would it take to build molecular machines that only let elements with a specific mass across a semi permeable barrier? I’m imagining it would be something like a protein ion transport channel except it discriminates based on mass instead of charge? ### Related * [[Concrete goals for an APM system]]