SINGLE MOLECULES SOLVATED IN PORES OF POLYACRYLAMIDE GELS

Individual fluorescent molecules and individual singly-labeled protein s have been observed in the water-filled pores of poly(acrylamide) gel s with far-field microscopy. The molecular range of motion is dramatic ally reduced by the gel framework, thus allowing single molecules to b e studied in an aqueous environment for long periods of time. For the small fluorophores, the gel restricts Brownian motion by approximately two orders of magnitude in each direction, thus greatly enhancing the molecule's detectability. In contrast to dry polymeric hosts, the gel is composed primarily of water and the majority of molecules remain i n solution, thus making these gels an ideal medium in which to utilize single molecule detection methods for the study of biological systems in vitro.