Water-dispersible curcumin nanoparticles were prepared by bottom-up antisolvent precipitation approach. A new high-throughput screening technique was developed for selecting appropriate ligands stabilizing the nanopar...Water-dispersible curcumin nanoparticles were prepared by bottom-up antisolvent precipitation approach. A new high-throughput screening technique was developed for selecting appropriate ligands stabilizing the nanoparticles in aqueous medium and improving their performance. The initial set of twenty-eight potential stabilizing ligands was evaluated based on their capacity to improve curcumin dispersibility in aqueous medium. The performance of four promising ligands(amino acid proline, polyphenol tannic acid, polycation Polyquaternium 10, and neutral polymer polyvinylpyrrolidone) was tested in ultrasound-aided antisolvent precipitation trials. Using the selected stabilizing ligands diminished the average particle size from ca. 1,200 to 170–230 nm, reduced their dispersity, improved stability, and allowed reaching curcumin concentration of up to 1.4 m M in aqueous medium. Storage stability of the aqueous nanodispersions varied from 2 days to 2 weeks, depending on stabilizing ligand. Studying the effects of ionic strength and pH on size and f-potential of the particles suggested that electrostatic forces and hydrophobic interactions could be the major factors affecting their stability. The ligand-protected nanoparticles showed minimal inhibitory concentration of 400 or500 μM toward Escherichia coli. We suggest that the presented screening approach may be useful for preparing nanoparticles of various poorly water-soluble bioactive materials.展开更多
Ligand-stabilized metal nanoclusters with atomic precision have garnered significant attention for applications in catalysis,biomedicine,and nanoelectronics due to their tunable structures and unique physicochemical p...Ligand-stabilized metal nanoclusters with atomic precision have garnered significant attention for applications in catalysis,biomedicine,and nanoelectronics due to their tunable structures and unique physicochemical properties[1-3].While transition metals such as Au,Ag,Pt,and Pd dominate the core composition,surface ligands are predominantly limited to phosphines,thiols,alkynes,and carbenes.Among these,N-heterocyclic carbenes(NHCs)have emerged as a superior ligand class due to their dual capacity for strongσ-donation andπ-back bonding,which stabilizes diverse metal oxidation states and enhances metal-ligand interactions.Notably,NHC-protected clusters exhibit exceptional thermal stability attributed to CH-π/π-πinteractions and enlarged HOMO-LUMO gaps compared to thiol or phosphine analogues.Despite progress,synthetic limitations persist due to NHCs'sensitivity under harsh conditions.Current methods rely on direct reduction of metal-carbene precursors or ligand exchange reactions,with heterogeneous NHC-capped systems remaining unexplored.展开更多
基金supported by the US-Israel Binational Agricultural Research and Development (BARD) Grant US-4680-13C
文摘Water-dispersible curcumin nanoparticles were prepared by bottom-up antisolvent precipitation approach. A new high-throughput screening technique was developed for selecting appropriate ligands stabilizing the nanoparticles in aqueous medium and improving their performance. The initial set of twenty-eight potential stabilizing ligands was evaluated based on their capacity to improve curcumin dispersibility in aqueous medium. The performance of four promising ligands(amino acid proline, polyphenol tannic acid, polycation Polyquaternium 10, and neutral polymer polyvinylpyrrolidone) was tested in ultrasound-aided antisolvent precipitation trials. Using the selected stabilizing ligands diminished the average particle size from ca. 1,200 to 170–230 nm, reduced their dispersity, improved stability, and allowed reaching curcumin concentration of up to 1.4 m M in aqueous medium. Storage stability of the aqueous nanodispersions varied from 2 days to 2 weeks, depending on stabilizing ligand. Studying the effects of ionic strength and pH on size and f-potential of the particles suggested that electrostatic forces and hydrophobic interactions could be the major factors affecting their stability. The ligand-protected nanoparticles showed minimal inhibitory concentration of 400 or500 μM toward Escherichia coli. We suggest that the presented screening approach may be useful for preparing nanoparticles of various poorly water-soluble bioactive materials.
文摘Ligand-stabilized metal nanoclusters with atomic precision have garnered significant attention for applications in catalysis,biomedicine,and nanoelectronics due to their tunable structures and unique physicochemical properties[1-3].While transition metals such as Au,Ag,Pt,and Pd dominate the core composition,surface ligands are predominantly limited to phosphines,thiols,alkynes,and carbenes.Among these,N-heterocyclic carbenes(NHCs)have emerged as a superior ligand class due to their dual capacity for strongσ-donation andπ-back bonding,which stabilizes diverse metal oxidation states and enhances metal-ligand interactions.Notably,NHC-protected clusters exhibit exceptional thermal stability attributed to CH-π/π-πinteractions and enlarged HOMO-LUMO gaps compared to thiol or phosphine analogues.Despite progress,synthetic limitations persist due to NHCs'sensitivity under harsh conditions.Current methods rely on direct reduction of metal-carbene precursors or ligand exchange reactions,with heterogeneous NHC-capped systems remaining unexplored.
