Currently, the most advanced method for the programmed assembly of nanometer-sized objects with well-controlled shapes and surface features uses DNA hybridization. Techniques like the DNA origami method or DNA “bricks” use the simple rules of complementary base pairing and placement of branched “Holliday” junctions between three or more DNA strands to generate complex two- and three-dimensional shapes. This enables DNA to serve as a highly programmable structural building block while stepping outside of the role of being the blueprint for cellular structure. Computer-assisted tools such as caDNAno and newly developed techniques for lab desk automation facilitate the rapid and precise creation of objects of virtually any shape on the nanometer scale.
Atomic Force Microscopy (AFM) is a tool for gaining precise structural and mechanical information about materials on a molecular scale. By scanning materials with a sharp tip just a few atoms in width, structural features can be resolved down to nanometer resolution. Furthermore, AFM-based force spectroscopy also allows the measurement of forces down to single piconewtons, and the local elastic properties of biological materials such as gels, cells and many more.