Pickering emulsions with stimuli responsive properties have attracted mounting research attention owing to their potential for on-demand destabilisation of emulsions. However, a combination of biocompatibility and long-term stability are essential...

Graphene oxide (GO) and other 2D-nanosheet materials exhibit a range of useful physical, chemical, electrical, and optical properties that may usher in the next generation of biomedical, bioimaging, or sensing technologies. One limitation of GO is its poor stability in concentrated electrolytes and other complex fluids that requires steric stabilizers, including surface grafted polymers, to overcome attractive van der Waals interactions. Here, we describe a simple, rapid, and highly effective method of modifying GO and other 2D-nanosheets with thick, grafted (bio)polymer brushes via the solution self-assembly of lubricin (LUB; a.k.a. PRG4), an antiadhesive glycoprotein. Atomic force microscopy (AFM) imaging and force measurements were used to characterize the morphology and nanomechanical response of these LUB−GO, 2D-nanosheet complexes (2D-NSC). These characterization studies reveal a strong correlation between the GO surface area and the thickness (i.e., molecular extension) of the grafted LUB brush caused by edge free volume effects. Likewise, this edge free volume influences the extension of the LUB brush structure more than 300 nm away from the edge, resulting in a transition region of increasing brush extension before reaching a fully extended state within the central regions of the 2D-NSC. Fitting AFM normal force measurements using an adapted Alexander−de Gennes polymer brush model also indicate that the edge free volume leads to a mechanical softening of the LUB brush due to the lateral spreading and/or deflection of LUB molecules under compression. Finally, the stability studies of 2D-NSCs dispersed in concentrated electrolyte solutions demonstrate the effectiveness of the grafted LUB brushes at inhibiting aggregation even in the harshest environments. 2D-NSCs thus represent a simple solution to modifying nanosheets with thick, multifunctional brushes with promising application in biosensing, bioimaging, catalysis, and biolubrication, where nanosheets must perform in concentrated electrolytes or complex fluids.

In drug delivery applications, particle‐based systems have been used widely due to their physicochemical properties such as size, shape, and surface charge to achieve desirable properties in intracellular environments. The way in which nanoparticles enter a biological cell is an important factor in determining their efficacy as drug carriers, their biodistribution, and toxicity. Most research thus far has focused on the comparison of spherical and rod‐like particles on cellular internalization and transport. Here, the synthesis of bowl‐shaped polydopamine (PDA) mesoporous nanoparticles with an average diameter of 200 nm and well‐controlled radially oriented mesochannels are reported. By incubating bowl‐shaped PDA nanoparticles and spherical nanoparticles with HeLa cells, their internalization behaviors are investigated using a suite of characterization techniques. Extensive experimental results demonstrate that bowl‐shaped PDA nanoparticles adhere to the cell more efficiently and a faster rate of cellular uptake of bowl‐shaped nanoparticles compared to their spherical counterparts. Overall, the cellular internalization behavior of particles is shape‐dependent, and such information is crucial in designing nanoparticles for biomedical applications.

The study showed that the antioxidant, anti-inflammatory, antiangiogenic and GST-inducing activities of betalains from red dragon fruit peels were enhanced through carbohydrate encapsulation. © 2016 Society of Chemical Industry.

A comprehensive study of cellular internalization mechanisms of nanoparticles is crucial to optimize their drug delivery efficacy, as endocytosis pathways will likely determine their biological fate. Particularly for polydopamine bowl-shaped mesoporous nanoparticles (PDA bowls), their anisotropic morphology provides enhanced cellular internalization efficiency with respect to their spherical counterparts, though the mechanism of this is not yet fully understood. Herein, we report a size-controlled synthesis of PDA bowls by changing different reaction parameters and investigated their size-dependent endocytosis pathways in the HeLa cell line. The cellular internalization behavior of PDA bowls was investigated by using a suite of characterization techniques including flow cytometry, confocal microscopy, and transmission electron microscopy. Obtained results demonstrated that the uptake efficiency of PDA bowls is significantly dependent on their size. Moreover, the size of bowls also plays an important role in the endocytosis pathways followed to internalize them into cells, which was investigated by blocking certain endocytosis pathways with biological inhibitors. Taken together, this work provides fundamental understanding of the impact of reaction parameters on sizecontrolled synthesis of PDA bowls and reveals the role of their size in regulating the cellular internalization pathways, providing key structure−function information for these unique particles, which pave the way to the optimization of engineering drug nanocarriers in cancer treatment with higher efficacy.