A hydrogel based on 1,3:2,4-dibenzylidenesorbitol (DBS), modified with acyl hydrazides which extracts gold/silver salts from model waste is reported, with preferential uptake of precious heavy metals over other common metals. Reduction of gold/silver salts occurs spontaneously in the gel to yield metal nanoparticles located on the gel nanofibers. High nanoparticle loadings can be achieved, endowing the gel with electrochemical activity. These hybrid gels exhibit higher conductances than gels doped with carbon nanotubes, and can be used to modify electrode surfaces, enhancing electrocatalysis. We reason this simple, industrially and environmentally relevant approach to conducting materials is of considerable significance.

A hydrogel based on 1,3:2,4-dibenzylidenesorbitol (DBS), modified with acyl hydrazides which extracts gold/silver salts from model waste is reported, with preferential uptake of precious heavy metals over other common metals. Reduction of gold/silver salts occurs spontaneously in the gel to yield metal nanoparticles located on the gel nanofibers. High nanoparticle loadings can be achieved, endowing the gel with electrochemical activity. These hybrid gels exhibit higher conductances than gels doped with carbon nanotubes, and can be used to modify electrode surfaces, enhancing electrocatalysis. We reason this simple, industrially and environmentally relevant approach to conducting materials is of considerable significance.

A simple approach to a patterned multidomain gel is reported, combining a pH-responsive low-molecular-weight gelator (LMWG) and a photoinducible polymer gelator (PG). Using SEM (scanning electron microscopy), NMR spectroscopy, and CD, we demonstrate that self-assembly of the LMWG network occurs in the presence of the PG network, but that the PG has an influence on LMWG assembly kinetics and morphology. The application of a mask during photoirradiation allows patterning of the PG network; we define the resulting system as a “multidomain gel”—one domain consists of a LMWG, whereas the patterned region contains both LMWG and PG networks. The different domains have different properties with regard to diffusion of small molecules, and both gelator networks can control diffusion rates to give systems capable of controlled release. Such materials may have future applications in multikinetic control of drug release, or as patterned scaffolds for directed tissue engineering.

This study investigates transgeden (TGD) dendrimers (polyamidoamine (PAMAM)-type dendrimers modified with rigid polyphenylenevinylene (PPV) cores) and compares their heparin-binding ability with commercially available PAMAM dendrimers. Although the peripheral ligands are near-identical between the two dendrimer families, their heparin binding is very different. At low generation (G1), TGD outperforms PAMAM, but at higher generation (G2 and G3), the PAMAMs are better. Heparin binding also depends strongly on the dendrimer/heparin ratio. We explain these effects using multiscale modelling. TGD dendrimers exhibit “shape-persistent multivalency”; the rigidity means that small clusters of surface amines are locally well optimised for target binding, but it prevents the overall nanoscale structure from rearranging to maximise its contacts with a single heparin chain. Conversely, PAMAM dendrimers exhibit “adaptive multivalency”; the flexibility means individual surface ligands are not so well optimised locally to bind heparin chains, but the nanostructure can adapt more easily and maximise its binding contacts. As such, this study exemplifies important new paradigms in multivalent biomolecular recognition.

A simple approach to a patterned multidomain gel is reported, combining a pH-responsive low-molecular-weight gelator (LMWG) and a photoinducible polymer gelator (PG). Using SEM (scanning electron microscopy), NMR spectroscopy, and CD, we demonstrate that self-assembly of the LMWG network occurs in the presence of the PG network, but that the PG has an influence on LMWG assembly kinetics and morphology. The application of a mask during photoirradiation allows patterning of the PG network; we define the resulting system as a “multidomain gel”—one domain consists of a LMWG, whereas the patterned region contains both LMWG and PG networks. The different domains have different properties with regard to diffusion of small molecules, and both gelator networks can control diffusion rates to give systems capable of controlled release. Such materials may have future applications in multikinetic control of drug release, or as patterned scaffolds for directed tissue engineering.

Die Anwendung multivalenter Wechselwirkungen ist eine leistungsfähige Strategie biologischer Systeme, um eine hochaffine molekulare Erkennung zu erzielen. Seit kurzem richtet die Aufmerksamkeit der Synthesechemie vermehrt auf die selbstorganisierte anstelle einer kovalenten Synthese zur Anordnung von Liganden. Dieser Ansatz bietet mehrere Vorteile, z. B. eine einfache Synthese/Assemblierung, gezielt einstellbare Morphologien und Liganden, die Möglichkeit zum Einbau mehrerer aktiver Einheiten und die responsive Natur der Selbstorganisation. Wir zeigen, dass selbstorganisierte Multivalenz eine Strategie mit fundamentaler Bedeutung für den Entwurf synthetischer Nanosysteme ist, die in biologische Reaktionswege eingreifen können und potenzielle Anwendungen in der Nanomedizin finden.

Multivalency is a powerful strategy for achieving high-affinity molecular recognition in biological systems. Recently, attention has begun to focus on using self-assembly rather than covalent scaffold synthesis to organize multiple ligands. This approach has a number of advantages, including ease of synthesis/assembly, tunability of nanostructure morphology and ligands, potential to incorporate multiple active units, and the responsive nature of self-assembly. We suggest that self-assembled multivalency is a strategy of fundamental importance in the design of synthetic nanosystems to intervene in biological pathways and has potential applications in nanomedicine.