RESUMO
Understanding drug-release kinetics is critical for the development of drug-loaded nanoparticles. We developed a J-aggregate-based Förster-resonance energy-transfer (FRET) method to investigate the release of novel high-drug-loading (50â wt %) nanoparticles in comparison with low-drug-loading (0.5â wt %) nanoparticles. Single-dye-loaded nanoparticles form J-aggregates because of the high dye-loading (50â wt %), resulting in a large red-shift (≈110â nm) in the fluorescence spectrum. Dual-dye-loaded nanoparticles with high dye-loading using FRET pairs exhibited not only FRET but also a J-aggregate red-shift (116â nm). Using this J-aggregate-based FRET method, dye-core-polymer-shell nanoparticles showed two release processes intracellularly: the dissolution of the dye aggregates into dye molecules and the release of the dye molecules from the polymer shell. Also, the high-dye-loading nanoparticles (50â wt %) exhibited a slow release kinetics in serum and relatively quick release in cells, demonstrating their great potential in drug delivery.
Assuntos
Portadores de Fármacos/química , Transferência Ressonante de Energia de Fluorescência/métodos , Nanopartículas/química , Polímeros/química , Liberação Controlada de Fármacos , Microscopia Eletrônica de TransmissãoRESUMO
Nitrogen-doped titania nanosheets with visible light response were synthesized by exfoliating a layered titanate with homogeneous nitrogen doping.
Assuntos
Amônia/química , Materiais Biocompatíveis/química , Luz , Nanoestruturas/química , Nitrogênio/química , Titânio/química , Microscopia de Força Atômica , TemperaturaRESUMO
A new type of nanocomposite ion-exchange membranes containing sulfonated polyethersulfone (sPES) polymer matrix and sulfonated surface-functionalized mesoporous silica (SS) inorganic fillers was prepared. Various characterizations revealed that the addition of inorganic fillers with different shapes had a significant influence on the membrane structure. The mesoporous inorganic fillers not only created extra pore and water channels, assisting the ionic migration and improving conductivity of the composites, but also provided additional fixed charge groups upon surface modification. This allows the Donnan exclusion to work effectively and thus improve the selectivity of membranes. It was proved that the incorporation of appropriate amount of SS additive could significantly improve the conductivity (up to 20 folds) and permselectivity (about 14%) of the sPES membranes. The performance of these newly developed membranes in desalination by electrodialysis was comparable with that of a commercial membrane (FKE).