What are the characteristics of gels used in capillary gel electrophoresis?

In capillary electrophoresis, two types of gels are commonly used: permanently coated gels and dynamically coated gels. Permanently coated gels are polymerized inside the capillary and bonded to the capillary wall. The porosity of these gels can be adjusted by changing the concentration of acrylamide and crosslinker, affecting solute mobility. Only electrokinetic injection is feasible with these rigid gels.

Dynamically coated gels can be dissolved in separation buffers and act as molecular sieves. They are easier to prepare than cross-linked polymers and offer improved separation reproducibility when replaced before each injection. Porosity can be adjusted by altering polymer concentration or molecular mass. Both hydrodynamic and electrokinetic injection techniques can be used with dynamically coated gels due to their low viscosity in buffer solutions.