Bitesize Bio takes you through a protocol to make your very own competent E. coli cells, which can be pretty expensive to buy. "One morning's work (with a bit of work ahead of time) is all it takes to make great electrocompetent E. coli prep," Nick writes, adding that you'd be able to get competencies of 1x1010, with a little practice. Some tips include: keeping everything fresh and chilled at all times, washing the cells in glycerol, starting with a lot of cells, and washing the glassware by hand before autoclaving to make sure that there is no detergent.
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