Question

What are the different methods by which cell can be made competent?

Answer 1

Choosing the ideal competent cells for your cloning applications and workflows is a critical component of success. Aspects to consider when selecting your competent E. coli strain include:

Transfection method – chemical versus electroporation

Transformation efficiency – bacterial strain and genotype

Downstream application – protein expression, library production, general cloning

Answer 2

There are two primary methods for transforming bacterial cells: heat shock and electroporation. In both cases, the bacterial cells have to be made competent or permeable to plasmids that you would like the cell to propagate. To create competent cells for either transformation method used, bacterial cells are grown to logarithmic phase and harvested. Cells growing exponentially can be rendered competent more easily than cells at other stages of growth. After harvesting, the cells are treated differently. Chemically competent cells are created using a series of cold salt washes to disrupt the cell membranes, preparing the cells to accept plasmid DNA . For electrocompetent cells, the cells are chilled and washed with cold deionized water and 10% glycerol . A low-salt environment is important when electrical currents are involved.