No abstract

Iron-based nanoscale coordination polymers as novel drug delivery systems for efficient HIV/AIDS therapy.

No abstract

The synthesis and structuration of a novel low-molecular-weight amphiphilic catechol compound is reported. The combination of a hydrophilic tail containing a catechol unit and a pyrene-based hydrophobic head favors solvent-tuned supramolecular assembly. Formation of hollow nanocapsules/vesicles occurs in concentrated solutions of polar protic and nonprotic organic solvents, whereas a fibril-like aggregation process is favored in water, even at low concentrations. The emission properties of the pyrene moiety allow monitoring of the self-assembly process, which could be confirmed by optical and electronic microscopy. In organic solvents and at low concentrations, this compound remains in its nonassembled monomeric form. As the concentration increases, the aggregation containing preassociated pyrene moieties becomes more evident up to a critical micellar concentration, at which vesicle-like structures are formed. In contrast, nanosized twist beltlike fibers are observed in water, even at low concentrations, whereas microplate structures appear at high concentrations. The interactions between molecules in different solvents were studied by using molecular dynamics simulations, which have confirmed different solvent-driven supramolecular interactions.

Two rationally-designed strategies for covalent bonding of fluorescent dyes in coordination polymer nanoparticles to achieve bifunctional fluorescent nanostructures have been developed. The first strategy was based on the synthesis of the coordination polymers structured as nanoparticles by coordination of Co II ions to two different catechol ligands containing free functional chemical groups (dopamine and 3,4dihydroxybenzaldehyde), and a bis-imidazol ligand (1,4bis(imidazole-1-ylmethyl)benzene, bix). Subsequently, different dyes namely fluorescein isothiocyanate (FITC), 1-pyrenebutanoic acid hydrazide (PBH) or Alexa Fluor ® 568 (A568) could be sequentially attached to the nanoparticles surface. The second strategy was focused on the pre-functionalization of catechol ligands with the corresponding dyes and afterward the coordination with the metal ions in presence of bix. In vitro studies demonstrated the internalization of the bifunctional nanoparticles and the persistence of the fluorescent properties after cell uptake without dye leaching.[a]

Miniaturization of coordination polymers to the nanoscale represents a unique opportunity to assemble a novel class of highly customizable functional materials that marry the rich diversity, chemistry and properties of coordination complexes to the advantages of nanomaterials. The new structures, which exhibit well-defined and dispersed morphologies, can allow for a proper correlation with their functionality, and therefore, enable the rational design of new generations of these nanostructures targeting specific desired properties. In this Chapter we will give a brief introduction to the rational fabrication of such functional nanostructures following different coordination polymerization mechanisms. The novel "smart" nanoscale coordination polymer particles (NCPs) exhibit interesting properties of relevance for different fields and applications, worth to mention Nanomedicine and Sensors. Herein we make a summary of the main results obtained in both areas that evidence the significance of this novel family of materials. For this, the review has been divided into two main sections. In the first part we revise general methodologies for cargo loading and delivery, including the design of stimuli-responsive systems. In the second section we will review the latest advances in the use of NCPs as chemical sensing platforms. These results open new avenues for all the possible applications that can be derived from the implications of CPPs on surfaces. Finally, a brief introduction to the new research line on 2D-coordination polymers will be outlined.