An injectable and self-healing collagen-gold hybrid hydrogel is spontaneously formed by electrostatic self-assembly and subsequent biomineralization. It is demonstrated that such collagen-based hydrogels may be used as an injectable material for local delivery of therapeutic agents, showing enhanced antitumor efficacy.

In recent years, emulsions stabilized by micro- or nanoparticles (known as Pickering emulsions) have attracted much attention. Micro- or nanoparticles, as the main components of the emulsion, play a key role in the preparation and application of Pickering emulsions. The existence of particles at the interface between the oil and aqueous phases affects not only the preparation, but also the properties of Pickering emulsions, affording superior stability, low toxicity, and stimuli-responsiveness compared to classical emulsions stabilized by surfactants. These advantages of Pickering emulsions make them attractive, especially in biomedicine. In this review, the effects of the characteristics of micro- and nanoparticles on the preparation and properties of Pickering emulsions are introduced. In particular, the preparation methods of Pickering emulsions, especially uniform-sized emulsions, are listed. Uniform Pickering emulsions are convenient for both mechanistic research and applications. Furthermore, some biomedical applications of Pickering emulsions are discussed and the problems hindering their clinical application are identified.

Chitosan-based nanoparticles (NPs) are widely used in drug delivery, device-based therapy, tissue engineering, and medical imaging. In this aspect, a clear understanding of how physicochemical properties of these NPs affect the cytological response is in high demand. The objective of this study is to evaluate the effect of surface charge on cellular uptake profiles (rate and amount) and intracellular trafficking. We fabricate three kinds of NPs (∼ 215 nm) with different surface charge via SPG membrane emulsification technique and deposition method. They possess uniform size as well as identical other physicochemical properties, minimizing any differences between the NPs except for surface charge. Moreover, we extend our research to eight cell lines, which could help to obtain a representative conclusion. Results show that the cellular uptake rate and amount are both positively correlated with the surface charge in all cell line. Subsequent intracellular trafficking indicates that some of positively charged NPs could escape from lysosome after being internalized and exhibit perinuclear localization, whereas the negatively and neutrally charged NPs prefer to colocalize with lysosome. These results are critical in building the knowledge base required to design chitosan-based NPs to be used efficiently and specifically.

Great progress has been made in the preparation and application of multi-shelled hollow micro-/nanostructures during the past decade. However, the synthetic methodologies and potential applications of these novel and interesting materials have not been reviewed comprehensively in the literature. In the current review we first describe different synthetic methodologies for multi-shelled hollow micro-/nanostructures as well as their compositional and geometric manipulation and then review their applications in energy conversion and storage, sensors, photocatalysis, and drug delivery. The correlation between the geometric properties of multi-shelled hollow micro-/nanostructures and their specific performance in relevant applications are highlighted. These results demonstrate that the geometry has a direct impact on the properties and potential applications of such materials. Finally, the emerging challenges and future development of multi-shelled hollow micro-/nanostructures are further discussed.