A method of forming a nanostructure comprises forming self-assembled nucleic acids on at least a portion of a substrate. The method further comprises contacting the self-assembled nucleic acids on the at least a portion of a substrate with a solution comprising at least one repair enzyme to repair defects in the self-assembled nucleic acids. The method may comprise repeating the repair of defects in the self-assembled nucleic acids on the at least a portion of a substrate until a desired, reduced threshold level of defect density is achieved. A semiconductor structure comprises a pattern of self-assembled nucleic acids defining a template having at least one aperture therethrough. At least one of the apertures has a dimension of less than about 50 nm.