N,N,N',N'-Tetramethylethylenediamine is used to catalyze the formation of free radicals from ammonium persulfate or riboflavin. The free radicals will cause acrylamide and bis-acrylamide to polymerize to form a gel matrix which can be used for sieving macromolecules such as nucleic acids and proteins. TEMED has been used in the coating for soft polymers, such as polyacrylamide, in capillaries for investigation by atom force microscopy. Microchips containing oligonucleotides and proteins immobilized within gel pads have been prepared using TEMED. It is also used used in the HPLC of small organic molecules.