Progress in sequencing deoxyribonucleic acid with an atomic force microscope

Atomic force microscope (AFM) images of single-stranded deoxyribonucleic acid (DNA) showing nucleotide resolution have been obtained using two sample preparation methods: DNA covalently attached to a polymerized lipid monolayer and then imaged under water and DNA on mica rinsed with a Ba(NO3)2 solution and then imaged under ethanol. Some of the bases were identified in the AFM image of DNA on polymerized lipid. Current problems in sequencing DNA with the AFM include movement of the DNA during imaging and the difficulty of reproducing experiments.