Protein-assisted stretching and immobilization of DNA molecules in a microchannel.

We demonstrate a novel technique we call "protein-assisted DNA immobilization" (PADI), to immobilize and stretch, but not overstretch, DNA molecules inside a micro/nanochannel with limited surface interactions while maintaining continuous hydration at physiological pH. The biological activity of the immobilized DNA molecules is confirmed by digesting the DNA with restriction enzymes in the microchannel. Single-molecule transcription, which has stringent requirements on the immobilized DNA with respect to surface interactions and stretched lengths, is also successfully demonstrated on DNA molecules immobilized by PADI. In addition to arraying DNA molecules for study of DNA-protein interactions, the immobilization method could be used to construct DNA-templated nanoelectronic devices.