Supramolecular Diversity through Click Chemistry: Switching from Nanomicelles to 1D-Nanotubes and Tridimensional Hydrogels
journal contributionposted on 12.11.2013, 00:00 by Mohyeddin Assali, Juan-José Cid, Inmaculada Fernández, Noureddine Khiar
The size and shape of nanoparticles are of prominent importance for their biological activities and for their application as smart drug delivery systems. Thus, synthetic designs allowing divergent synthesis of nanoscale materials with controlled size, morphology, and surface chemistry are currently highly desirable, but they remain a major challenge. Herein, we report a simple method for the creation of supramolecular diversity from structurally related diacetylenic-based glycolipids. We have found that neoglycolipids with an amide function between the hydrophilic and hydrophobic part of the amphiphile afford tridimensional micelles, while those having a triazole self-organize into 1D-nanotubes. Additionally, at higher concentrations, the clicked amphiphiles form hydrogels through three-dimensional networks of bundled nanotubes. Photopolymerization of the obtained nanomaterials leads to the formation of conjugated polydiacetylene backbone of alternating enyne groups, which rigidify glyconanomaterial structures enhancing their physical stability. The obtained nanostructures were extensively characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques, enabling the confirmation of the formation of tubular structures in water for all triazolo-substituted neoglycolipids and micellar structures for the glycolipid containing an amide group. This fact refutes the so-called isosteric character of 1,2,3-triazole and amide groups, at least, at the supramolecular level and point out to the possibility of using the CuAAC between azides and alkynes to create supramolecular diversity at the nanoscale. The functionality of the gel was, moreover, evaluated as a nanocontainer for the incarceration and controlled release of the antitumoral topotecan.