Leyang Zhang

Preparation and drug release behaviors of nimodipine-loaded poly(caprolactone) poly(ethylene oxide) polylactide amphiphilic copolymer nanoparticles

Amphiphilic block copolymers, poly(caprolactone)-poly(ethylene glycol)-poly(lactide) (PCELA), were synthesized by ring opening polymerization of caprolactone and lactide initiated with the hydroxyl groups of poly(ethylene glycol) (PEG). These copolymers could form micelle-like nanoparticles due to their amphiphilic characteristic. From the observation of transmission electron microscopy (TEM), the nanoparticles exhibited a regular spherical shape with core-shell structure. The critical micelle concentrations (CMC) of these nanoparticles in water were decreased as molecular weight of PEG decreased. The particle sizes obtained by dynamic light scattering of these nanoparticles were in the range of 100-200 nm, and increased as the hydrophobic property of the nanoparticles increased. Nimodipine as a model drug was loaded in these nanoparticles to investigate the drug release behavior. It was found that the chemical composition of the nanoparticles was a key factor in controlling nanoparticle size, nanoparticle yields, drug-entrapment efficiency, and drug release behavior. When the PEG content is about 2% (wt), the release profile of PCELA nanoparticles appeared to follow zero-order kinetics.

Dual‐Functional Alginic Acid Hybrid Nanospheres for Cell Imaging and Drug Delivery

An effective and facile approach to prepare gold-nanoparticle-encapsulated alginic acid-poly[2-(diethylamino)ethyl methacrylate] monodisperse hybrid nanospheres (ALG-PDEA-Au) is developed by using monodisperse ALG-PDEA nanospheres as a precursor nanoparticulate reaction system. This approach utilizes particle-interior chemistry, which avoids additional reductant or laborious separation process and, moreover, elegantly ensures that all the gold nanoparticles are located inside the hybrid nanospheres and every nanosphere is loaded with gold nanoparticles. These obtained ALG-PDEA-Au hybrid nanospheres have not only uniform size, similar surface properties, and good biocompatibility but also unique optical properties provided by the embedded gold nanoparticles. It is demonstrated that negatively charged ALG-PDEA-Au hybrid nanospheres can be internalized by human colorectal LoVo cancer cells and hence act as novel optical-contrast reagents in tumor-cell imaging by optical microscopy. Moreover, these hybrid nanospheres can also serve as biocompatible carriers for the loading and delivery of an anti-cancer drug doxorubicin. In vitro cell viability tests reveal that drug-loaded ALG-PDEA-Au hybrid nanospheres exhibit similar tumor cell inhibition to the free drug doxorubicin. Therefore, the obtained hybrid nanospheres successfully combine two functions, that is, cell imaging and drug delivery, into one single system, and may be of great application potential in other biomedical-related areas.

Synthesis and antitumoral activity of gelatin/polyoxometalate hybrid nanoparticles.

Surfactant-free gelatin/heptamolybdate (HM) hybrid nanoparticles are prepared by a simple and environmentally friendly approach utilizing the electrostatic interaction between anionic HM and the zwitterionic gelatin. The obtained nanoparticles have a tunable size and very high HM loading content up to about 70%. In vitro and in vivo experiments prove that the gelatin/HM hybrid nanoparticles exhibit significantly better antitumor activity than plain ammonium heptamolybdate solution. Therefore, the gelatin/HM hybrid nanoparticles reported here may serve as a prototype platform for polymer/polyoxometalate (POM) hybrid nanoparticles as cancer treatment agents and hence open up more opportunities to maximize the potential of POM-based pharmaceutical agents.