Pure and Applied Chemistry

Abstract: Self-replicating nanorobots were foreseen in technological dreams and visions whose scientific ground found solid criticism from chemical and physical reasoning. If one, however, views such constructs as three-dimensionally defined noncovalent nanoscaffolding of a multitude of modular functions whose array is replicatable in a nonautonomous way, many pieces of technology needed for their implementation became recently available. Gold cluster-labeled molecules were remotely controlled by GHz radio frequency causing local and selective inductive heating, and monoconjugable thermostable gold clusters will become commercially available soon. Charged molecules were electrophoretically steered and manipulated on the surface of microelectrode array chips. Surface-promoted replication and exponential amplification of DNA analogs (SPREAD) may find particular applications for the cloning and copying of informational nanostructures on the surface of such chips. Synthetic trisoligonucleotidyl junctions were reported as covalent building blocks for noncovalent DNA nanostructures, and it was shown that kinetic control during noncovalent synthesis favors small and defined nanostructures instead of polymeric networks. Very recently, it was demonstrated that functionalized DNA nanoscaffolds with stiff tensegrity such as tetrahedra self-assemble from maximally instructed sets of 3- or [3+1]-arm junctions, and that the connectivity information in such nanoscaffolds can be copied. The implications of these developments are discussed with respect to a possible implementation scheme for the issue of the title.