Photocontrolled self-assembly of silica nanoparticles at two scales

Evaporation-Induced Self-Assembly of Small Peptide-Conjugated Silica Nanoparticles

Self-assembly processes guide disordered molecules or particles into long-range organized structures due to specific supramolecular interactions among the building entities. Herein, we report a unique evaporation-induced self-assembly (EISA) strategy for four different silica nanoparticle systems obtained through peptide functionalization of the particle surface. First, covalent peptide-silica coupling was investigated in detail, starting with the grafting of a single amino acid (L-serine) and expanded to specific small peptides (up to four amino acids) and transferred to different particle types (MCM-48-type MSNs, solid nanoparticles, and newly developed virus-like nanoparticles). These materials were investigated regarding their ability to undergo EISA, which was shown to be independent of particle type and amount of peptide anchored to their surface. This EISA-based approach provides new possibilities for the design of future advanced drug delivery systems, engineered hierarchical sorbents, and nanocatalyst assemblies.

The Many Ways to Assemble Nanoparticles Using Light

The ability to reversibly assemble nanoparticles using light is both fundamentally interesting and important for applications ranging from reversible data storage to controlled drug delivery. Here, the diverse approaches that have so far been developed to control the self-assembly of nanoparticles using light are reviewed and compared. These approaches include functionalizing nanoparticles with monolayers of photoresponsive molecules, placing them in photoresponsive media capable of reversibly protonating the particles under light, and decorating plasmonic nanoparticles with thermoresponsive polymers, to name just a few. The applicability of these methods to larger, micrometer-sized particles is also discussed. Finally, several perspectives on further developments in the field are offered.

A novel long-alkyl-chained acylhydrazone-based supramolecular polymer gel for the ultrasensitive detection and separation of multianalytes

By rationally introducing multi-self-assembly driving forces and coordination binding sites into the same molecule, a designed functional gelator, G, was synthesized. Next, a novel supramolecular polymer material, OGV (1% DMSO), was constructed and used for the ultrasensitive detection and separation of multianalytes in gel states. Interestingly, OGV showed a fluorescent ultrasensitive response for the Hg2+ and Fe3+ ions in water. Moreover, by introducing these metal ions into the OGV, stable metal ion-coordinated supramolecular metallogels (HgG and FeG) were formed, which could sense CN- and H2PO4- in water with high selectivity and sensitivity.