Toward Highly Stable Anode for Secondary Batteries: Employing TiO2 Shell as Elastic Buffering Marix for FeOx Nanoparticles

Transition metal oxides are considered promising anode materials for next-generation lithium-ion and sodium-ion batteries (LIBs and SIBs) because of their high theoretical capacities; however, their practical application is limited by the detrimental large volume expansion that occurs upon cycling. In this work, a rationally designed TiO₂ @Fe@FeO_x nanocomposite encapsulated by a TiO₂ shell with unique core-shell structure is synthesized and exhibits outstanding electrochemical performance as an anode in LIBs and SIBs. The nanocomposite exhibits a reversible capacity of 619.2 mAh g^-1 at 1 A g^-1 with a coulombic efficiency over 99.5% after 1000 cycles when used as a LIB anode. The nanocomposite also exhibits superior sodium storage performance (267 mAh g^-1 at 50 mA g^-1 , capacity retention of 65.4% after 1000 cycles at 200 mA g^-1 ). The TiO₂ shell serves as a strong conformal layer and soft matrix that can tolerate the volume expansion and maintain the structural integrity of the anode during discharging and charging. Moreover, the open active diffusion channels of the shell contribute to high ion diffusivity and improved ionic, and electronic diffusion. These findings indicate that adoption of TiO₂ coating is an effective strategy to optimize the electrochemical performance of transition metal oxide anode materials.

Soft Matrix Promotes Cardiac Reprogramming via Inhibition of YAP/TAZ and Suppression of Fibroblast Signatures

Direct cardiac reprogramming holds great potential for regenerative medicine. However, it remains inefficient, and induced cardiomyocytes (iCMs) generated in vitro are less mature than those in vivo, suggesting that undefined extrinsic factors may regulate cardiac reprogramming. Previous in vitro studies mainly used hard polystyrene dishes, yet the effect of substrate rigidity on cardiac reprogramming remains unclear. Thus, we developed a Matrigel-based hydrogel culture system to determine the roles of matrix stiffness and mechanotransduction in cardiac reprogramming. We found that soft matrix comparable with native myocardium promoted the efficiency and quality of cardiac reprogramming. Mechanistically, soft matrix enhanced cardiac reprogramming via inhibition of integrin, Rho/ROCK, actomyosin, and YAP/TAZ signaling and suppression of fibroblast programs, which were activated on rigid substrates. Soft substrate further enhanced cardiac reprogramming with Sendai virus vectors via YAP/TAZ suppression, increasing the reprogramming efficiency up to ∼15%. Thus, mechanotransduction could provide new targets for improving cardiac reprogramming.

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Hydrogel culture reveals the role of mechanotransduction in cardiac reprogramming

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Soft ECM comparable with native myocardium promotes cardiac reprogramming

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Soft ECM promotes cardiac reprogramming via YAP/TAZ/fibroblast signaling inhibition

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Soft ECM promotes Sendai virus vector-mediated cardiac reprogramming

Highly Sensitive and Durable Structured Fibre Sensors for Low-Pressure Measurement in Smart Skin

Precise measurements of low pressure are highly necessary for many applications. This study developed novel structured fibre sensors embedded in silicone, forming smart skin with high sensitivity, high durability, and good immunity to crosstalk for precise measurement of pressure below 10 kPa. The transduction principle is that an applied pressure leads to bending and stretching of silicone and optical fibre over a purposely made groove and induces the axial strain in the gratings. The fabricated sensor showed high pressure sensitivity up to 26.8 pm/kPa and experienced over 1,000,000 cycles compression without obvious variation. A theoretical model of the sensor was presented and verified to have excellent agreement with experimental results. The prototype of smart leg mannequin and wrist pulse measurements indicated that such optical sensors can precisely measure low-pressure and can easily be integrated for smart skins for mapping low pressure on three-dimensional surfaces.

0.1 kilopascal difference for mechanophenotyping: soft matrix precisely regulates cellular architecture for invasion

Current knowledge understands the mesenchymal cell invasion in a 3D matrix as a combined process of cell-to-matrix adhesion based cell migration and matrix remodeling. Excluding cell invasion stimulated by cytokines and chemokines, the basal cell invasion itself is a complicated process that can be regulated by matrix ligand type, density, geometry, and stiffness, etc. Understanding such a complicated biological process requires delicate dissections into simplified model studies by altering only one or two elements at a time. Past cell motility studies focusing on matrix stiffness have revealed that a stiffer matrix promotes 2D X-Y axis lateral cell motility. Here, we comment on two recent studies that report, instead of stiffer matrix, a softer matrix promotes matrix proteolysis and the formation of invadosome-like protrusions (ILPs) along the 3D Z axis. These studies also reveal that soft matrix precisely regulates such ILPs formation in the stiffness scale range of 0.1 kilopascal in normal cells. In contrast, malignant cells such as cancer cells can form ILPs in response to a much wider range of matrix stiffness. Further, different cancer cells respond to their own favorable range of matrix stiffness to spontaneously form ILPs. Thus, we hereby propose the idea of utilizing the matrix stiffness to precisely regulate ILP formation as a mechanophenotyping tool for cancer metastasis prediction and pathological diagnosis.