Reinforcement with clay nanosheets, [12] biominerals, [13] cellulose, [14,15] or polymeric fibers [16] enhances tensile stiffness of the hydrogels. Noncovalent interactions, i.e., ionic, [17][18][19] hydrophobic interactions, [20] and hydrogen bonding, [20,21] increase the compression stiffness or viscoelasticity of the materials. Nevertheless, imparting multiple and mutually contradictory properties, as exemplified by high stiffness, toughness, and water content, results in materials that compromise one essential property at the expense of another. Replicating the combination of physical metrics of natural soft tissues remains challenging. For instance, hydrogels with covalently crosslinked nanoreinforcement have a high tensile modulus of ≈2 MPa at low strains, [12] but they experience fracture or catastrophic softening under tensile strains above a few percent due to the limited deformability of the nanofillers. Hydrogels with multiple polymer networks can be stretched by ≈17 times even with a notch in the sample, [10] but the softness of the constituent polymers result in a tensile modulus of only ≈30 kPa, which is two to four orders of magnitude lower than those of cartilage, ligaments, or tendons. Increasing the stiffness of these hydrogels would otherwise be associated with the sacrifice of water content that is essential for cellular viability in biomedical applications. [11,13] Dense nacre-like composites based on stiff inorganic and soft organic components can exhibit high stiffness and toughness, [22,23] but similar mechanics are difficult to achieve in water-rich (e.g., >70 wt%) embodiments due to the chemical and physical limitations of the mineral constituents. Replicating the physical behaviors of load-bearing soft tissues would require a new class of stiff nanoscale components that are capable of forming porous and reconfigurable networks.We recently reported that para-aramid, commonly known as Kevlar, can form a nanofibrous dispersion in dimethyl sulfoxide (DMSO). [24] Solution-processable nanoscale versions of Kevlar, i.e., aramid nanofibers (ANFs), retain the high mechanical properties of their macroscale parent, and these materials have served as the building blocks for high-strength flexible conductors and battery separators. [24,25] In the context of this study, a key fact is that ANFs with diameters of 5-30 nm and lengths of 3-10 µm form networked structures when DMSO is exchanged with water. [25] Their structural similarity to biological nanofibers, such as those from collagen and those that display extensive branching, [26] inspired us to explore ANFs as the stiff Load-bearing soft tissues, e.g., cartilage, ligaments, and blood vessels, are made predominantly from water (65-90%) which is essential for nutrient transport to cells. Yet, they display amazing stiffness, toughness, strength, and deformability attributed to the reconfigurable 3D network from stiff collagen nanofibers and flexible proteoglycans. Existing hydrogels and composites partially achieve some of the mechanical propertie...

Highlights d Periostin deficiency inhibits colorectal tumor formation in mice d Periostin is mainly secreted by fibroblasts to promote tumor cell proliferation d Periostin promotes YAP/TAZ nuclear localization and IL-6 expression in tumor cells d IL-6 promotes fibroblast activation and periostin expression during tumorigenesis

In the present paper, we have developed for the first time the electrochemically shape-controlled synthesis in deep eutectic solvents (DESs) for the preparation of Pt nanocrystals enclosed by high-index facets. Monodispersed concave tetrahexahedral Pt nanocrystals (THH Pt NCs) have been prepared through this new route. The concave THH Pt NCs were characterized by SEM, TEM, and AFM. The as-prepared concave Pt NCs are bounded with {910} and vicinal high-index facets, which exhibit superior catalytic activity and stability to those of the commercial Pt black catalyst for ethanol electrooxidation. We have demonstrated also that the electrochemically shape-controlled synthesis in DESs proves advantageous in controlling the size and shape of Pt NCs without the addition of seeds, surfactants, or other chemicals and could be applied in the synthesis of other noble metal NCs with high surface energy and high catalytic activity.

Designing chiral materials to manipulate the biological activities of cells has been an important area not only in chemistry and material science, but also in cell biology and biomedicine. Here, we introduce monolayer plasmonic chiral Au nanoparticle (NP) films modified with l- or d-penicillamine (Pen) to be developed for cell growth, differentiation, and retrieval. The monolayer films display high chiroptical activity, with circular dichroism values of 3.5 mdeg at 550 nm and 26.8 mdeg at 775 nm. The l-Pen-NP films accelerate cell proliferation, whereas the d -Pen-NP films have the opposite effect. Remote irradiation with light is chosen to noninvasively collect the cells. The results demonstrate that left circularly polarized light improves the efficiency of cell detachment up to 91.2% for l-Pen-NP films. These findings will facilitate the development of cell culture in biomedical application and help to understand natural homochirality.