Recent advances in click chemistry applied to dendrimer synthesis.

Dendrimers are monodisperse polymers grown in a fractal manner from a central point. They are poised to become the cornerstone of nanoscale devices in several fields, ranging from biomedicine to light-harvesting. Technical difficulties in obtaining these molecules has slowed their transfer from academia to industry. In 2001, the arrival of the "click chemistry" concept gave the field a major boost. The flagship reaction, a modified Hüisgen cycloaddition, allowed researchers greater freedom in designing and building dendrimers. In the last five years, advances in click chemistry saw a wider use of other click reactions and a notable increase in the complexity of the reported structures. This review covers key developments in the click chemistry field applied to dendrimer synthesis from 2010 to 2015. Even though this is an expert review, basic notions and references have been included to help newcomers to the field.

Nanoscale tools to selectively destroy cancer cells.

We present experimental data that demonstrate the potential of synthetic crown ether modified peptide nanostructures to act as selective and efficient chemotherapeutic agents that operate by attacking and destroying cell membranes.

The Dawn of Thiol-Yne Triazine Triones Thermosets as a New Material Platform Suited for Hard Tissue Repair.

The identification of a unique set of advanced materials that can bear extraordinary loads for use in bone and tooth repair will inevitably unlock unlimited opportunities for clinical use. Herein, the design of high-performance thermosets is reported based on triazine-trione (TATO) monomers using light-initiated thiol-yne coupling (TYC) chemistry as a polymerization strategy. In comparison to traditional thiol-ene coupling (TEC) systems, TYC chemistry has yielded highly dense networks with unprecedented mechanical properties. The most promising system notes 4.6 GPa in flexural modulus and 160 MPa in flexural strength, an increase of 84% in modulus and 191% in strength when compared to the corresponding TATO system based on TEC chemistry. Remarkably, the mechanical properties exceed those of polylactide (PLA) and challenge poly(ether ether ketone) PEEK and today's methacrylate-based dental resin composites. All the materials display excellent biocompatibility, in vitro, and are successfully: i) molded into medical devices for fracture repair, and ii) used as bone adhesive for fracture fixation and as tooth fillers with the outstanding bond strength that outperform methacrylate systems used today in dental restoration application. Collectively, a new era of advanced TYC materials is unfolded that can fulfill the preconditions as bone fixating implants and for tooth restorations.

Effect of AIE substituents on the fluorescence of tetraphenylethene-containing BODIPY derivatives.

A series of BODIPY derivatives with tetraphenylethene (TPE) moieties were designed and synthesized. The effect of positions and numbers of substitution groups on the fluorescence of the BODIPYs was investigated. Theoretical calculation and single crystal structures proved that the TPE substitution groups on the 8-position of BODIPY contributed little to the conjugation, but benefited the aggregated state emission. On the other hand, the substitutions on the 3- or 5-position of BODIPY through vinyl bridges increased the conjugation length, and generated big coplanar π-conjugated structures with poor aggregated state emission. The compound with bright aggregated state emission has been further fabricated into biocompatible fluorescent nanoparticles and used as effective fluorescent contrast agents for intracellular imaging.

Characterization of channel-forming peptide nanostructures.

We have prepared fluorescent analogs of known ion-channel-forming synthetic peptide nanostructures. These analogs were designed as probes to gain insight about the mechanism by which self-assembling amphiphilic peptides interact with lipid membranes. Conformational studies demonstrated that the labeled analogs retain their propensity to adopt a strong helical conformation in 2,2,2-trifluoroethanol and lipid bilayers. Attenuated total reflectance results indicated that the fluorescent peptide nanostructures are under an incorporation equilibrium between two forms, adsorbed at the surface or incorporated within the bilayer, similar to their unlabeled counterparts. However, when using a HeLa mimicking membrane, the proportion of peptide nanostructures in the transmembrane orientation decreases significantly. Finally, we were able to show by confocal microscopy studies that fluorescent analogs internalized into HeLa cells and localized into both the membranes of inner organelles and the cell membrane.