Patent ID: 8518226

Claim:
A method for isolation of supercoiled nucleic acid of interest contained within a fluid sample containing at least one other contaminating supercoiled nucleic acid of size greater than the supercoiled nucleic acid of interest comprising introducing said fluid sample into a microfluidic capillary containing a trapping matrix at a first position, applying an electric field to the fluid sample such that supercoiled nucleic acid is encouraged to move within said microfluidic capillary containing a trapping matrix to a second position, distal to said first position; wherein the electric field applied is chosen so as to be greater than the critical electric field for said at least one contaminating nucleic acid, and less than the critical electric field for said supercoiled nucleic acid of interest; wherein the critical electric field is the minimum electric field required to trap a supercoiled nucleic acid of given size; and wherein the electric field is applied for a period of time sufficient to isolate the supercoiled nucleic acid of interest.