Multivalent and Multifunctional Calixarenes in Bionanotechnology

The key features of calixarene derivatives as multivalent ligands for biomacromolecules and as multifunctional catalysts are reviewed herein. The ease of functionalization and the possibility to control the regio- and stereochemical disposition of multiple ligating units around a central core allow to obtain ligands with high affinity and selectivity especially for proteins and nucleic acids. The hydrophilic/lipophilic character can also be finely tuned, allowing to obtain monomeric hybrid derivatives or amphiphiles able to self-assemble alone or in co-formulation with lipids to give nanoparticles and liposomes that incorporate calixarenes. The knowledge acquired up to now sheds light on the future applications of calixarenes in bionanotechnology and nanomedicine

Provocation Through Narratives: New Speculative Design Tools for Human-Non-Human Collaborations

In a complex and changing world, design is called to act to nurture and provoke critical reflections regarding wicked, complex, and interconnected issues, becoming a sensemaking agent that, exploiting its speculative methods, uses narratives as an inquiry tool, as a co-design tool, and as a provocative tool. Through the presentation and analysis of a provotype designed by the authors, the research aims to define new speculative tools for human-non-human collaborations and highlight how design narratives may be involved within more-than-human discourses

correction moulding calixarenes for biomacromolecule targeting

Correction for 'Moulding calixarenes for biomacromolecule targeting' by Marta Giuliani et al., Chem. Commun., 2015, 51, 14140–14159

Halogen bonds direct the solid state architectures of a multivalent iodopropargylcalix[4]arene

The iodoalkynyl group is a ditopic synthon, able to act as a halogen bond (XB) donor through the iodine atom and as an XB acceptor on the C≡C triple bond. With the aim of exploring the self-assembly properties via XB of calix[4]arene macrocycles containing this synthon, we synthesized and characterized a tetra(iodopropargyl)calix[4]arene (3). In the solid state, all the iodoalkynyl units of 3 are involved in intermolecular XB interactions as both donors and acceptors, resulting in a two-dimensional network of calixarene double layers. On the contrary, in the cocrystal of 3 with 4,4′-bipyridine, a bidentate XB acceptor, the iodine atoms are halogen bonded to the pyridine nitrogen atoms forming a one-dimensional ribbon of calixarenes alternated by two 4,4′-bipyridine units. These supramolecular architectures are the first example of solid-state networks of calixarene derivatives where the self-assembly is mostly driven by XBs

Calixarene-decorated liposomes for intracellular cargo delivery

Liposomes equipped at the outer membrane with positively charged calixarenes show improved efficiency in cargo delivery. This is facilitated by the interaction between the macrocycle units and heparan sulfate proteoglycans surrounding the cell

Calixarenes Incorporating Sulfonamide Moieties: Versatile Ligands for Carbonic Anhydrases Inhibition

Carbonic anhydrases (CAs) continue to represent a relevant pharmaceutical target. The need of selective inhibitors and the involvement of these metalloenzymes in many multifaceted diseases boost the search for new ligands able to distinguish among the different CA isoforms, and for multifunctional systems simultaneously able to inhibit CAs and to interfere with other pathological events by interacting with additional targets. In this work, we successfully explored the possibility of preparing new CAs ligands by combining calixarenes with benzensulfonamide units. Inhibition tests towards three human CA isoforms evidenced, for some of the ligands, Ki values in the nanomolar range and promising selectivity. X-ray and molecular modeling studies provided information on the mode of binding of these calixarene derivatives. Thanks to the encouraging results and the structural features typical of the calixarene scaffold, it is then possible to plan for the future the design of multifunctional inhibitors for this class of widely spread enzymes

Upper-rim acidic peptidocalixarenes as crystal growth modifiers

Calix[4]arenes functionalised at the upper rim with acidic amino acid residues are found to have a significant impact on the crystal growth of model mineral systems, calcium carbonate and barium sulphate. The aspartic acid derivative is found to be most efficacious, matching or exceeding the impact of commercial phosphonate-based scale inhibitors. In some cases, the modified morphologies are found to be similar to those induced by proteins isolated from biomineralised systems

Docetaxel-Loaded Nanoparticles Assembled from β-Cyclodextrin/Calixarene Giant Surfactants: Physicochemical Properties and Cytotoxic Effect in Prostate Cancer and Glioblastoma Cells

Giant amphiphiles encompassing a hydrophilic β-cyclodextrin (βCD) component and a hydrophobic calix[4]arene (CA4) module undergo self-assembly in aqueous media to afford core-shell nanospheres or nanocapsules, depending on the nanoprecipitation protocol, with high docetaxel (DTX) loading capacity. The blank and loaded nanoparticles have been fully characterized by dynamic light scattering (DLS), ζ-potential measurements and cryo-transmission electron microscopy (cryo-TEM). The data are compatible with the distribution of the drug between the nanoparticle core and the shell, where it is probably anchored by inclusion of the DTX aromatic moieties in βCD cavities. Indeed, the release kinetics profiles evidenced an initial fast release of the drug, which likely accounts for the fraction hosted on the surface, followed by a slow and sustained release rate, corresponding to diffusion of DTX in the core, which can be finely tuned by modification of the giant amphiphile chemical structure. The ability of the docetaxel-loaded nanoparticles to induce cellular death in different prostate (human LnCap and PC3) and glioblastoma (human U87 and rat C6) cells was also explored. Giant amphiphile-based DTX formulations surpassing or matching the antitumoral activity of the free DTX formulation were identified in all cases with no need to employ any organic co-solvent, thus overcoming the DTX water solubility problems. Moreover, the presence of the βCD shell at the surface of the assemblies is intended to impart stealth properties against serum proteins while permitting nanoparticle surface decoration by supramolecular approaches, paving the way for a new generation of molecularly well-defined antitumoral drug delivery systems with improved specificity and efficiency. Altogether, the results provide a proof of concept of the suitability of the approach based on βCD-CA4 giant amphiphiles to access DTX carriers with tunable properties