Modified DNA immobilized on bioreactive self-assembled monolayer on gold for dynamic force microscopy imaging in aqueous buffer solution

Recent advances in DNA specimen preparation techniques for dynamic scanning force microscopy based on terminal anchoring of the DNA segments on bioreactive self-assembled monolayers on ultraflat gold surfaces or on the gold surfaces themselves are presented DNAs of well-defined lengths and sequences carrying amino- or thiol-modified nucleotides at each end have been prepared, DNA imaging in the ac mode has been reproducibly achieved in buffer solution. Since the DNA segments are anchored at their ends only, their backbones are lying free on the self-assembled monolayer and are accessible to DNA-protein interaction. These procedures are suitable to follow in real time biological processes involving DNA. (C) 1996 American Vacuum Society.