We have encapsulated free-standing planar lipid membranes in a polymer hydrogel via in situ photopolymerization. These encapsulated membranes were measured to last at least 5 days and provided a stable environment for single-molecule measurements of incorporated alpha-hemolysin channel proteins. The translocation of single-stranded DNA through alpha-hemolysin incorporated into these encapsulated membranes is slowed over 100 times relative to that of the gel-free state. These stabilized membranes, therefore, have application to the single-molecule analysis of DNA as well as broader application to biomolecular sensors, membrane protein biophysical studies, and drug discovery.