Polymeric Bowl-Shaped Nanoparticles: Hollow Structures with a Large Opening on the Surface

Polymeric bowl-shaped nanoparticles (BNPs) are anisotropic hollow structures with large openings on the surface, which have shown advantages such as high specific area and efficient encapsulation, delivery and release of large-sized cargoes on demand compared to solid nanoparticles or closed hollow structures. Several strategies have been developed to prepare BNPs based on either template or template-free methods. For instance, despite the widely used self-assembly strategy, alternative methods including emulsion polymerization, swelling and freeze-drying of polymeric spheres, and template-assisted approaches have also been developed. It is attractive but still challenging to fabricate BNPs due to their unique structural features. However, there is still no comprehensive summary of BNPs up to now, which significantly hinders the further development of this field. In this review, the recent progress of BNPs will be highlighted from the perspectives of design strategies, preparation methods, formation mechanisms, and emerging applications. Moreover, the future perspectives of BNPs will also be proposed.

Spontaneous formation of giant vesicles with tunable sizes based on jellyfish-like graft copolymers

For self-assembly studies, a series of “jellyfish-like” graft copolymers with short hydrophilic backbones and long hydrophobic branch chains was adopted. It was found that these special graft copolymers in 1,4-dioxane–water mixtures could self-assemble into giant vesicles with diameter in the range of 0.5–54 μm.

Galactosylated chitosan-polycaprolactone nanoparticles for hepatocyte-targeted delivery of curcumin

Galactosylated chitosan-polycaprolactone (Gal-CH-PCL) copolymers with a galactosylation degree of around 10% and varied PCL percentages less than 40 wt% were synthesized and used to produce nanoparticles for delivering curcumin. Some nanoparticles with encapsulation efficiency of 70% or higher and sizes changing from 100 to 250 nm were able to deliver curcumin in a controlled manner. PCL content in Gal-CH-PCLs was found to be a key factor for governing the release behavior of nanoparticles. Hepatocyte-targeted characteristic of nanoparticles was confirmed using human hepatocellular carcinoma (HepG2) cells. In comparison to free curcumin, curcumin-loaded Gal-CH-PCL nanoparticles well retained its anticancer activity. At an equivalent curcumin-dose of around 20 μg/mL that was found to be relatively safe to human normal liver cells, the results obtained from flow-cytometry revealed that some optimized Gal-CH-PCL nanoparticles showed more than 6-fold increasing abilities to induce the apoptosis and necrosis of HepG2 cells during 72 h treatment compared to free curcumin.