Recently, there has been a growing interest in artificial skin on hydrogels as a potential alternative for animal testing to evaluate the efficacy and safety of new drugs or cosmetics. Synthetic polymers have been wid...
Recently, there has been a growing interest in artificial skin on hydrogels as a potential alternative for animal testing to evaluate the efficacy and safety of new drugs or cosmetics. Synthetic polymers have been widely used due to their superior physicochemical properties. However, synthetic polymers such as polyvinyl alcohol (PVA) are limited by their poor biocompatibility and cell adhesion. Combining synthetic and natural polymers can improve these properties. Therefore, in this study, we aimed to investigate the effect of alginate and chitosan addition to PVA-based hydrogels on protein adsorption, cell viability and cell attachment. The addition of chitosan decreased protein adsorption, which was caused by the changes in electrostatic charge by PVA-chitosan interaction and changes in surface roughness. Primary human fibroblast cells cultured on PVA, PVA-alginate and PVA-chitosan had >80% viability which indicates the cytocompatibility of the hydrogels. More importantly, alginate and chitosan also improved the cell attachment on the PVA-based hydrogels. Taken together, the addition of both alginate and chitosan has the potential to improve PVA-based hydrogels for artificial skin application.
Circularly polarized luminescence (CPL) with tunable chirality is currently a challenging issue in the development of supramolecular nanomaterials. We herein report the formation of helical nanoribbons which grow into...
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Circularly polarized luminescence (CPL) with tunable chirality is currently a challenging issue in the development of supramolecular nanomaterials. We herein report the formation of helical nanoribbons which grow into helical tubes through dynamic helicity inversion. For this, chiral Pt II complexes of terpyridine derivatives, namely S - trans - 1 and R - trans - 1 , with respective S - and R -alanine subunits and incorporating trans -double bonds in the alkyl chain were prepared. In DMSO/H 2 O (5 : 1 v / v ), S - trans - 1 initially forms a fibrous self-assembled product, which then undergoes dynamic transformation into helical tubes (left-handed or M -type) through helical ribbons (right-handed or P -type). Interestingly, both helical supramolecular architectures are capable of emitting CPL signals. The metastable helical ribbons show CPL signals ( g lum =±4.7×10 −2 ) at 570 nm. Meanwhile, the nanotubes, which are the thermodynamic products, show intense CPL signals ( g lum =±5.6×10 −2 ) at 610 nm accompanied by helicity inversion. This study provides an efficient way to develop highly dissymmetric CPL nanomaterials by regulating the morphology of metallosupramolecular architectures.
We fabricated a full-dielectric three-dimensional photonic-crystal cavity containing an ultrahigh-mobility two-dimensional electron gas. By applying a strong perpendicular magnetic field, we created Landau polaritons ...
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ISBN:
(数字)9781957171050
ISBN:
(纸本)9781665466660
We fabricated a full-dielectric three-dimensional photonic-crystal cavity containing an ultrahigh-mobility two-dimensional electron gas. By applying a strong perpendicular magnetic field, we created Landau polaritons originating from the ultrastrong coupling of electrons with cavity modes.
We demonstrate tunable, giant, and structure-induced deep-ultraviolet circular dichroism in macroscopically chiral assemblies of racemic carbon nanotubes prepared using two approaches: mechanical-rotation-assisted vac...
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ISBN:
(纸本)9781957171258
We demonstrate tunable, giant, and structure-induced deep-ultraviolet circular dichroism in macroscopically chiral assemblies of racemic carbon nanotubes prepared using two approaches: mechanical-rotation-assisted vacuum filtration and chiral stacking of aligned carbon nanotubes.
LiOsO3 synthesized under high pressure in recent years is a rare metal since it undergoes a nonpolar to polar phase transition at Ts=140K. Forming a polar axis through a phase transition in a metal seems against commo...
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LiOsO3 synthesized under high pressure in recent years is a rare metal since it undergoes a nonpolar to polar phase transition at Ts=140K. Forming a polar axis through a phase transition in a metal seems against common sense. It is also not clear whether the transition to a polar phase in the oxide fits the mechanism predicted by Anderson and Blount in 1965. As monitored by an anomaly of resistivity in LiOsO3 at Ts reported recently, Ts increases under pressure. The structural study under high pressure could give us a useful clue for understanding how dipoles form in this metallic oxide. Here, we report the identification of a polar phase of LiOsO3 at room temperature under high pressure by using in situ probes of Raman and synchrotron x-ray diffraction. In the Raman study, the pressure-induced modes and their responses to polarized light, the linewidth change, the peak profile change, and mode softening have been directly compared with the corresponding changes of LiOsO3 on cooling through Ts at ambient pressure. Whereas a complete set of Raman modes from the R3c phase can be found at P≥15.5GPa, a Raman mode of the R3c phase appears in the R3¯c phase at 4.11 GPa. A significant drop in the linewidth occurs at 12.6 GPa that coincides with the critical pressure for the phase transition to the polar phase detected by x-ray diffraction. Fitting the peak profile of a Raman mode to the Fano formula also indicates a clear change of electron-phonon coupling at 16 GPa. In contrast to a sharp structural transition to the polar phase at Ts under ambient pressure, our results reveal all the structural ingredients to facilitate the polar phase over a broad range of pressure. A bond valence sum analysis has been introduced to reveal the local structural instability under pressure. The transition to the polar phase in metallic LiOsO3 is solely caused by optimizing the local structure in order to make the bond valence sum close to the formal valence of the Li ion.
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