Development of rapid microwave-mediated and low-temperature bacterial transformations

The introduction of exogenous DNA into Escherichia coli is a cornerstone of molecular biology. Herein, we investigate two new mechanisms for bacterial transformation involving either the use of microwave irradiation or a freeze–thaw protocol in liquid nitrogen. Ultimately, both methods afforded successful transfer of plasmid DNA into bacterial cells, with the freeze–thaw technique yielding efficiencies of ~105. More importantly, both techniques effectively eliminated the need for the preparation of competent cells.