DNA nanotubes are promising materials with potential applications in medicine, nanotechnology and biotechnology fields. Their unique versatility is the result of their high aspect ratio and encapsulation potential, rigidity, relative ease of preparation and biocompatibility.[1] Our goal is to couple the DNA nanotubes-assembly with a controllable surface patterning in order to generate robust, programmable and functional scaffolds for the assembly of other species such as proteins, cells, etc. These materials would play an increasingly important role in a diverse range of applications, such as drug delivery, diagnostics, tissue engineering, ‘smart’ optical systems and biosensing. In order to obtain higher quality materials, control on their formation is highly desirable. We have envisioned that single molecule spectroscopy provides the right tool set to tackle the formation kinetics, structural and dynamic studies of these novel nanostructures. We are currently involved in investigating, via single molecule spectroscopy methodologies, the assembly dynamics of DNA nanotubes. Here, we have demonstrated a step by step bottom-up assembly of DNA nanotubes by following their growth on the surface after adding sequentially Cy3-labbeled DNA-rungs and linkers: This was confirmed by single-molecule photobleaching analysis. I will describe in this presentation the details of our studies and the structural and dynamic information gained on the new DNA-structures. Our studies constitute a step towards achieving a higher-order control of the assembly of the nanostructures.1. (a) Aldaye, F. A.; Lo, P. K.; McLaughlin, C. K.; Karam, P.; Cosa, G.; Sleiman, H. F.; Nature Nanotech. 2009, 4, 349-352. (b) Lo, P.K.; Karam, P.; Aldaye, F.A.; McLaughlin, C.K.; Hamblin, G.D.; Cosa, G.; Sleiman, H.F. Nature Chemistry, 2010, 2, 319-328. (c) Lo, P.K.; Altvater, F.; Sleiman, H.F. J. Am. Chem. Soc., 2010, 132, 10212-10214.