Supramolecular self-assembly of conjugated diacetylenic amphiphile-tethered ligands photopolymerize to afford polydiacetylene (PDA) functional liposomes. Upon specific interaction with a variety of biological analytes in aqueous solution, PDA exhibits rapid colorimetric transitions. The PDA nanoassemblies, which are excellent membrane mimics, include an ene–yne polymeric reporter responsible for the chromatic transitions and the molecular recognition elements that are responsible for selective and specific binding to the biological target. A bottleneck in the fabrication of these colorimetric biosensors is the preparation of the diacetylenic monomer embedded with the recognition element of choice. In the present work, we make use of copper-catalyzed azide–alkyne cycloaddition (CuAAC) as key step in the preparation of sugar-coated liposome biosensors. The regioselective click ligation of the triacetylenic N-(2-propynyl)pentacosa-10,12-diynamide (NPPCDAM) with a variety of mannose- and lactose-tethered azides afforded chemo- and regioselectively the corresponding 1,2,3-triazole. The obtained diacetylenic monomers were incorporated efficiently into vesicles to afford functional mannose- and lactose-coated glycoliposomes. The obtained PDA-based click glycoliposomes have been characterized by using transmission electronic microscopy (TEM), dynamic light scattering (DLS), and UV/Vis spectroscopy. The efficiency of the reported approach was demonstrated by the rapid optimization of the hydrophilic spacer between the lipidic matrix and the mannose head group for the colorimetric detection of Concavalin A.
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.