polyacrylamidgel

Polyacrylamide gel is a solid polymeric matrix formed from polyacrylamide that is produced by free-radical polymerization of acrylamide monomers crosslinked with a bifunctional agent, typically N,N'-methylenebisacrylamide. The resulting gel is a transparent, mechanically stable network used as a medium for electrophoretic separation of macromolecules.

The pore size and mechanical properties of the gel are controlled by the total acrylamide concentration and the level of crosslinking. Higher acrylamide content yields smaller pores, improving resolution for smaller molecules. Gradient gels, which vary acrylamide concentration across the gel, allow simultaneous separation over a broad range of sizes.

Applications include protein analysis by polyacrylamide gel electrophoresis (PAGE). Denaturing PAGE uses SDS to unfold proteins, separating them by molecular weight, while native PAGE preserves conformations to separate by size and charge. Polyacrylamide gels are also used for high-resolution separation of nucleic acids in DNA sequencing and mutation analysis, as well as for certain types of microsatellite and fragment analyses. The gel matrix is compatible with many staining and blotting techniques and can be used in combination with various buffers and additives to tailor separation conditions.

Preparation and safety notes: gels are cast from solutions of acrylamide, bisacrylamide, buffer, and polymerization initiators such as ammonium persulfate and TEMED. Acrylamide monomer is neurotoxic and a potential carcinogen; residual monomer in gels should be handled with appropriate safety precautions, including gloves and proper waste disposal. Polymerized gels are generally considered less hazardous but should still be handled with care.