A pulse-deposition method for scanning tunneling microscopy of deoxyribonucleic acid on graphite

Abstract
Images of three different synthetic DNAs have been obtained by scanning tunneling microscopy (STM) following their deposition on graphite using a voltaic pulse. DNA applied to the STM tip is desorbed during a 4 V/10-mu-s pulse and deposited intact onto the surface of highly oriented pyrolytic graphite. Images of 22, 47, and 100 base-pair molecules show that deposition occurs in close proximity to the tunneling tip and that the molecules appear to deposit singly or in highly oriented groups.