Life processes function by the activity of complex interacting molecular systems. Advances in nanostructure science and technology are providing powerful tools for investigating those systems. Developments such as atomic force microscopy, luminescent quantum dots, and nanofabricated probes have provided new capabilities for molecular and cell biology. The function of biomolecules, cellular components, and organelles and the interaction of living cells with their environment can now be explored in exquisite detail with nanoscale probes and devices. Materials and devices engineered at the nanometer scale are being developed and employed in biochemical analysis, medical diagnostics, and therapeutic devices. With the ability to understand, manipulate, and harness enzymes, receptors, and other biomolecules, new types of biosensors are emerging and new research approaches to biological systems are becoming possible.