A small molecular machine based on a rotaxane molecule autonomously added three amino acids in a programmed order to a seed tripeptide to form a hexapeptide

Electrons from a scanning tunneling microscope tip turn a five-arm rotor connected via a single ruthenium atom bearing to a tripod anchoring the molecular motor to a gold surface.

A theoretical proposal for optical tweezers and an experimental optical focusing device both depend upon electromagnetic waves trapped and guided along metal-insulator interfaces. Will these advances provide tools for manipulating molecular building blocks?