Bionic Fish-Scale Surface Structures Fabricated via Air/Water Interface for Flexible and Ultrasensitive Pressure Sensors.

In recent years, wearable and flexible sensors have attracted considerable research interest and effort owing to their broad application prospects in wearable devices, robotics, health monitoring, and so on. High-sensitivity and low-cost pressure sensors are the primary requirement in practical application. Herein, a convenient and low-cost process to fabricate a bionic fish-scale structure poly(dimethylsiloxane) (PDMS) film via air/water interfacial formation technique is presented. High-sensitivity flexible pressure sensors can be constructed by assembling conductive films of graphene nanosheets into a microstructured film. Thanks to the unique fish-scale structures of PDMS films, the prepared pressure sensor shows excellent performance with high sensitivity (-70.86% kPa-1). In addition, our pressure sensors can detect weak signals, such as wrist pulses, respiration, and voice vibrations. Moreover, the whole process of pressure sensor preparation is cost-effective, eco-friendly, and controllable. The results indicate that the prepared pressure sensor has a profitable and efficient advantage in future applications for monitoring human physiological signals and sensing subtle touch, which may broaden its potential applications in wearable devices.

Novel Deep-Eutectic-Solvent-Infused Carbon Nanofiber Networks as High Power Density Green Battery Cathodes.

Redox flow batteries (RFBs) have emerged as a promising candidate for large-scale energy storage because of the flexible design for high energy, power, and safety. In this study, FeCl3·6H2O/urea composite deep eutectic catholyte (FeU-DEC)-infused self-standing carbon nanofiber (CNF) was synthesized for green and high power density RFB through industrially available processes. FeU-DEC-infused CNF displayed an extremely high power density (874 mW/g) as well as high capacity (27.28 mAh/g) derived from high theoretical capacity of FeU-DEC (89.24 mAh/g) in addition to the advantages of the FeU-DEC characteristics (e.g., nonflammable, biodegradable, facile preparation). This is because of the large electroactive area derived from the high surface area of CNF and superlyophilicity of FeU-DEC on CNFs. Furthermore, we compared the wettability of CNF with other electrodes, as well as the chemical stability and electrode performance, based on topological wetting analysis using parameters of fiber radius, fiber interval, the equilibrium contact angle of FeU-DEC on electrodes, and surface tension of FeU-DEC, giving wetting threshold for FeU-DEC on fibrous electrodes. The wetting analysis are applied not only for FeU-DEC, but also for a wide range of other DECs and deep eutectic anolyte. This work contributes to the further development of green and high-performance RFBs.

Facile synthesis of a high electrical and ion conductivity junction-less 3D carbon sponge electrode for self-standing lithium ion battery anode.

Lithium ion batteries (LIB) are the most extensively researched and developed batteries. Currently, LIBs are used in various applications such as electric vehicles (EV), hybrid EVs (HEV), plug-in HEVs, and energy storage systems. However, their energy density is insufficient and further improvement is required. In this study, we propose the facile synthesis of a self-standing, junction-less 3D carbon sponge electrode (3DCS) for improving the energy density. A self-standing structure can improve the energy density by reducing non-active materials such as binders and current collectors, in electrodes. We use a kitchenware melamine sponge as the carbon precursor. The utilization of materials mass-produced by existing facilities is crucial for ensuring availability and low costs. Such characteristics are imperative for industrialization. These self-standing 3DCS electrodes, fabricated using available low-cost melamine sponges, demonstrate high charge-rate characteristics with a capacity retention of 81.8% at 4000 mA g-1 and cycle durability with 95.4% capacity retention after 500 cycles, without current collector, binder, and conductive additives. This high availability, low-cost material with excellent characteristics is beneficial for research institutions and companies that do not have facilities.

A Lubricant-Sandwiched Coating with Long-Term Stable Anticorrosion Performance.

Lubricant-infused surface(s) (LIS) bioinspired by the Nepenthes pitcher plant are receiving enormous attention owing to their excellent hydrophobicity as well as their self-healing ability. Thus, they have been applied as anticorrosion coatings. However, the loss of lubricant mediated by vapor or other liquids deteriorates their functions. Herein, we introduce a lubricant-inserted (sandwiched) microporous triple-layered surface (LIMITS) that prevents the sudden loss of lubricant. The sandwiched lubricant gradually self-secretes toward the surface, resulting in long-term stability even under water. The LIMITS prevented the corrosion of the Fe plate for at least 45 days, which is much superior to a conventional LIS coating. This work opens an avenue for the application of slippery coating materials that are stable under water and will also promote the development of anticorrosion coating in various industries.

The Pleckstrin Homology Domain of Diacylglycerol Kinase η Strongly and Selectively Binds to Phosphatidylinositol 4,5-Bisphosphate.

Type II diacylglycerol kinase (DGK) isozymes (δ, η, and κ) have a pleckstrin homology domain (PH) at their N termini. Here, we investigated the lipid binding properties of the PHs of type II DGK isozymes using protein-lipid overlay and liposome binding assays. The PH of DGKη showed the most pronounced binding activity to phosphatidylinositol (PI) 4,5-bisphosphate (PI(4,5)P2) among the various glycero- and sphingolipids including PI 3,4,5-trisphosphate, PI 3,4-bisphosphate, PI 3-phosphate, PI 4-phosphate, and PI 5-phosphate. Moreover, the PI(4,5)P2binding activity of the DGKη-PH was significantly stronger than that of other type II DGK isozymes. Notably, compared with the PH of phospholipase C (PLC) δ1, which is generally utilized as a cellular PI(4,5)P2- probe, the DGKη-PH is equal to or superior than the PLCδ1-PH in terms of affinity and selectivity for PI(4,5)P2 Furthermore, in COS-7 cells, GFP-fused wild-type DGKη1 and its PH partly translocated from the cytoplasm to the plasma membrane where the PLCδ1-PH was co-localized in response to hyperosmotic stress in an inositol 5-phosphatase-sensitive manner, whereas a PH deletion mutant did not. Moreover, K74A and R85A mutants of DGKη-PH, which lack the conserved basic amino acids thought to ligate PI(4,5)P2, were indeed unable to bind to PI(4,5)P2and co-localize with the PLCδ1-PH even in osmotically shocked cells. Overexpression of wild-type DGKη1 enhanced EGF-dependent phosphorylation of ERK, whereas either K74A or R85A mutant did not. Taken together, these results indicate that the DGKη-PH preferentially interacts with PI(4,5)P2and has crucial roles in regulating the subcellular localization and physiological function of DGKη. Moreover, the DGKη-PH could serve as an excellent cellular sensor for PI(4,5)P2.