Nanoelectromechanical systems: Tuning in to a graphene oscillator.

interactions occurring within the specific phase of the polymer–nanotube complex. This approach could be relevant for the development of smart devices for in situ functional healing actions activated by a signal transmitted from a sensing element on selective responses to a metabolite. Despite recent advances7, however, to become fully operational, smart devices based on carbon nanotube materials still need to overcome some limitations. Considering that the optoelectronic properties of the graphitic tubular framework are chirality-dependent, the main bottleneck for their use remains the unavailability of structurally and chirally homogeneous carbon nanotubes. Furthermore, strategies for wiring the sensing element to an operative unit also need to be developed. For example, functional groups introduced in several locations along the carbon nanotube (possibly including the inner cavity) could be used to confine pharmacologically active molecules to be released in situ when the recognition event occurs. Carbon nanotube–polymer complexes such as those developed by Strano and co-workers are particularly amenable for achieving this level of structural complexity, because they allow integration of the polymeric unit with dynamic covalent8 and non-covalent9 linkages that are responsive to a stimulus10. Such developments take the field a step closer to the construction of multifunctional smart devices, such as those for in situ drug delivery. ❐ Davide Bonifazi is at the Namur Research College (NARC) and Department of Chemistry, University of Namur, 5000 Namur, Belgium, and at the Department of Pharmaceutical and Chemical Sciences, University of Trieste, 34127 Trieste, Italy. e-mail: [email protected]