Endothelial dysfunction contributes to diabetic macrovascular complications. Sirtuin 1 (SIRT1) protects against diabetic vasculopathy. SRT2104 is a novel SIRT1 activator and was not previously studied for its effects on diabetes-induced aortic endothelial dysfunction. Additionally, whether or to what extent deacetylation of P53, a substrate of SIRT1, is required for the effects of SIRT1 activation was unclear, given the fact that SIRT1 has multiple targets. Moreover, little was known about the pathogenic role of P53 in diabetes-induced aortic injury. To these ends, diabetes was induced by streptozotocin in C57BL/6 mice. The diabetic mice developed enhanced aortic contractility, oxidative stress, inflammation, P53 hyperacetylation and a remarkable decrease in SIRT1 protein, the effects of which were rescued by SRT2104. In HG-treated endothelial cells (ECs), siRNA and SRT2104 produced similar effects on the induction of SIRT1 and the inhibition of P53 acetylation, oxidative stress and inflammation. Interestingly, SRT2104 failed to further enhance these effects in the presence of siRNA. Moreover, P53 activation by nutlin3a completely abolished SRT2104's protection against HG-induced oxidative stress and inflammation. Further, forced activation of P53 by nutlin3a increased aortic contractility in the healthy mice and generated endothelial oxidative stress and inflammation in both the normal glucose-cultured ECs and the aortas of the healthy mice. Collectively, the present study demonstrates that P53 deacetylation predominantly mediates SRT2104's protection against diabetes-induced aortic endothelial dysfunction and highlights the pathogenic role of P53 in aortic endothelial dysfunction.

Activation of nuclear factor erythroid 2-related factor 2 (NRF2) has been found to ameliorate diabetic testicular damage (DTD) in rodents. However, it was unclear whether NRF2 is required for these approaches in DTD. Epigallocatechin gallate (EGCG) is a potent activator of NRF2 and has shown beneficial effects on multiple diabetic complications. However, the effect of EGCG has not been studied in DTD. The present study aims to explore the role of NRF2 in both self and EGCG protection against DTD. Therefore, streptozotocin-induced diabetic C57BL/6 wild type (WT) and Nrf2 knockout (KO) mice were treated in the presence or absence of EGCG, for 24 weeks. The Nrf2 KO mice exhibited more significant diabetes-induced loss in testicular weight and spermatozoa count, and increase in testicular apoptotic cell death, as compared with the WT mice. EGCG activated NRF2 expression and function, preserved testicular weight and spermatozoa count, and attenuated testicular apoptotic cell death, endoplasmic reticulum stress, inflammation, and oxidative damage in the WT diabetic mice, but not the Nrf2 KO diabetic mice. The present study demonstrated for the first time that NRF2 plays a critical role in both self and EGCG protection against DTD.

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As one of the most promising intelligent materials, polymeric hydrogel actuators could produce reversible shape change upon external stimuli. Although complex shape deformation from 2D to 3D have been achieved, the realization of actuating behavior from 3D to 3D is still a significant challenge. Herein, an effective strategy to develop a novel bilayer hollow spherical hydrogel actuator is proposed. Through immersing a Ca2+ incorporated gelatin core into alginate solution, an ionic‐strength‐responsive alginate layer will be formed along the gelatin core via alginate–Ca2+ crosslinks, and then another thermo‐responsive alginate‐poly(2‐(dimethylamino)ethyl methacrylate)(Alg‐PDMAEMA) layer is introduced to achieve a bilayer hydrogel with ionic strength and temperature dual responsiveness. A hollow hydrogel capsule could be obtained if a spherical gelatin core is applied, and it could produce complex shape deformations from 3D to 3D upon the trigger of ionic strength and temperatures changes. The present work may offer new inspirations for the development of novel intelligent polymeric hydrogel actuators.

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AbstractThe intelligent poly N,N-dimethylacrylamide hydrogel material system with high mechanical strength and the 3D printable property was prepared via in situ free radical polymerization under vacuum successfully. With the increase in nanofibrillated cellulose (NFC) content, stress and strain of hydrogels increased gradually. As the effective reinforcement, NFC enhanced the crosslinking density, which realized the controllable regulation of rheology behaviors including viscosity, storage modulus, and loss modulus of hydrogels. Combined with the swelling rate and the existence of the gel–sol transition point, a hydrogel with 10 mg/mL NFC was treated as the 3D printing ink of hydrogel actuators. Variation of printing parameters significantly affected self-driven deformations. The hydrogel actuators with 90°/0° and 45°/135° configurations owned bending and spiral deformations, respectively. Actuators with a larger length–width ratio owned a lower pitch value. The precise anisotropic swelling property of the printed bilayer structure was the self-driven deformation mechanism of hydrogel actuators, which provided material candidates for the preparation of soft robots and actuators.

Antifogging surfaces with unique properties to migrate severe fog formation have gained extensive interest, which is of particular interest for transparent substrates to obtain high visibility and transparency. To date, a large number of strategies including superhydrophilic or superhydrophobic surfaces and titanium dioxide (TiO2)-based composite coatings have been developed based on different mechanisms. Although these surfaces exhibit effective antifogging properties, the rigid nanostructures, cumbersome preparation, and the need for UV light excitation largely limit their widespread applications. Herein, we report a zwitter-wettable antifogging and frost-resisting coating through a fast UV-curable cross-linking of copolymer with benzophenone groups. A series of random copolymers consisting of hydrophilic hydroxyethyl methacrylate (HEA), hydrophobic methyl methacrylate (MMA), and benzophenone-based acrylate units are developed by thermally triggered free-radical polymerization. Upon UV light irradiation, a highly efficient antifogging/frost-resisting coating is covalently bonded on a polycarbonate plate surface, maintaining a light transmission higher than 85%, which was confirmed in both high and low temperature anti-fog tests. Moreover, the wetting behaviors reveal that the antifogging performance exhibited by the zwitter-wettable surface mainly relies on its surface water-adsorbing capability to imbibe condensed water vapor on the surface outmost layer. Notably, the antifogging/frost-resisting behaviors can be well regulated by adjusting the hydrophilic/hydrophobic units, due to the proper balance between the water-adsorption and coating stability. Owing to its simplicity, low-cost preparation and high efficiency, this UV-curable acrylate antifogging coating may find a wide range of applications in various display devices in analytical and detection instruments.

The polyacrylamide (AAm)-chitosan (CS)-N,N′-methylene bisacrylamide (Bis) bilayer shape memory hydrogel actuators with high mechanical strength were successfully prepared via efficient in-situ free radical polymerization. The hydrogels exhibited high swelling and shape memory bending/unbending properties. Increasing Bis contents enhanced the crosslinking density and maintained the hydrophilic property of hydrogels, providing the microstructure and swelling anisotropy for construction of bilayer structure. Attributed to the enough polymerization on interface, bilayer hydrogels owned high bonding strength. With the increase of Bis content, the swelling bending degree of bilayer hydrogel actuators increased. Based on the mechanism of formation and disappearance of coordination of CS-metal ion, bilayer hydrogel actuators exhibited efficient shape memory property. The intelligent swelling and shape memory properties enriched the multiply deformation patterns of bilayer shape memory hydrogels, providing the potential applications in soft actuators, soft sensors and medical carriers.