Transformative Self-Assembly of Hybrid Nanocomposite Rings

Abstract

Active assembly processes facilitated by biological molecular motors (e.g., kinesin) are a promising candidates for producing complex, non-equilibrium nanostructures currently unattainable through conventional self-assembly methods. Such systems involve surface-adhered kinesin motors that propel biotinylated microtubules (MTs) across a surface, which in turn assemble into spools and ring nanocomposites upon introduction of streptavidin-coated quantum dots. In the present work, we describe the effects of structural and compositional heterogeneity of the MT building blocks on the behavior and morphology of the resulting ring nanocomposites. Heterostructured, segmented MTs with varying molar ratios of biotinylated and non-biotinylated segments were generated through the head-to-tail self-assembly of different MT populations, and subsequently used to assemble ring composites. Here, ring structures evolve from open loops to tightly packed rings upon increasing concentration of biotinylated segments. Moreover, preferential release of non-biotinylated segments from ring structures accompanied by reduction in length of the liberated MTs was observed for all ratios. Interestingly, the released MTs retained functionality and therefore were able to transiently or permanently incorporate into the composite structures. Overall, this work provides crucial insights for future development of dynamic and adaptive self-regulating multifunctional nanostructures. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.