clipped from: www.vivo.colostate.edu A commonly-used means of recovering DNA from polyacrylamide gels is by the so-called "crush and soak" method. The slice of polyacrylamide containing DNA is crushed in a microcentrifuge using a plastic pipet tip, and incubated with constant shaking in elution buffer (high salt) at 37C for several hours. The polyacrylamide pieces are then eliminated by centrifugation or by passing the mixture through a plug of siliconized glass wool. Finally, DNA is recovered by ethanol precipitation.
DNA can also be recovered from polyacrylamide by use of certain types of silica gel particles, as described above for recovery from agarose. However, small (< 100 bp) fragments of DNA are very difficult to elute from standard glass particles.