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The development of eco-friendly and light-weighted solid-state electrolytes with a wide electrochemical window is critical to apply flexible energy storage devices for powering wearable and implantable electronics. Herein, we report the first demonstration of a quasi solid-state hydrogel electrolyte leveraging the formation of “interfacial wetting water” for facile two-dimensional ion transports instead of typical diffusion in bulk-like water. The hydrogel electrolyte exhibits a wide electrochemical window (2.5 V) in electrical double layer capacitance (EDLC) cell with an extremely effective low salt concentration (6.8 m), 3.1 times lower than the well-known water-in-salt electrolyte (WiSE, 21 m), and a small water retention (24 wt%). Besides, a significant toughness (ultimate tensile strength of 420 kPa and elongation of 6,000%) is achieved. The flexible supercapacitor demonstrates the high specific energy density of 39.1 Wh•kg−1 at 0.5 A•g−1 and 7.6 Wh•kg−1 at power density of 6218 W•kg−1, as well as a subdued self-discharge profile. This interfacial water dominated hydrogel electrolyte provides new directions in designing high-voltage hydrogel electrolyte for safe and sustainable soft energy storage devices.

Injectable cell-based hydrogels allow surgical operation in a minimally invasive way for articular cartilage lesions but the chondrocytes in the injectable hydrogels are difficultly arrayed and fixed at the site of interest to repair the cartilage tissue. In this study, an injectable hyaluronic acid–polyacrylic acid (HA–pAA) hydrogel was first synthesized using hyaluronic acid–cyclodextrin (HA–CD) and polyacrylic acid–ferrocene (pAA–Fc) to provide cell-delivery and self-healing. To promote the cell fixation and alignment, porous poly(lactic-co-glycolic acid) (PLGA) magnetic microcapsules (PPMMs) with glutathione (GSH) loaded and iron oxide nanoparticles (IO) located in the shell were designed. The GSH-loaded PPMMs with layer-by-layer (LbL) assembly of hyaluronic acid (HA) and GSH (LbL-PPMMs) can provide a two-stage rapid and slow release of GSH to modulate the self-healing of the HA–pAA hydrogel at the injured site. Furthermore, the chondrocytes embedded in the HA–pAA hydrogel could be delivered through CD44 receptors on the HA polymer chains of LbL-PPMMs toward the surface of the damaged site by an internal magnetic force. The composite hydrogel system of chondrocytes/LbL-PPMMs/HA–pAA can provide the damaged cartilage with a more even and smooth surface than other groups in a rabbit model after 8 weeks of implantation. In addition, the chondrocytes in the deep zone tissue exhibit a columnar array, similar to the cell arrangement in normal cartilage tissue. Together with the cell navigation behavior and GSH release from the LbL-PPMM/HA–pAA hydrogel, a full closure of lesions on the cartilage tissue can be achieved. Our results demonstrate the highly promising potential of the injectable LbL-PPMM/HA–pAA system in cartilage tissue repair.

Serious side effects from chemotherapies are the main problem with cancer treatments. To solve these issues, precision cancer nanomedicine based on natural therapeutic materials is developed, which enables specifically apoptosis by interacting with genetic mutation in cancer cells, while leaving normal cells unaffected. Here, we report a novel nanomedicine (CuQDA/IO@HA) composed of hyaluronic acid (HA) / copper ion (Cu(II))-chelated dextran-aldehyde (DA)-quercetin (Q) with dual targeting for synthetic lethal therapy. The CuQDA/IO@HA prepared using a ratio of metal/Q at 0.5:1 resulted in a stable particle structure with uniform particle distribution. The CuQDA/IO@HA can specifically target and induce specific cytotoxicity in BRCA-mutant cancer cells in vitro. Combination treatment with CuQDA/IO@HA and magnetic navigation can induce poly (ADP-ribose) polymerase (PARP) inhibition and DNA damage in BRCA-mutant triple-negative breast cancer (TNBC) via CD44 targeting. The dual-targeting CuQDA/IO@HA can extend the median survival of the BRCA-mutant xenograft mice from 34 to 61 days in comparison to Q treatment alone in vivo, which is attributed to the significant increase in γH2AX, leading to significant apoptosis. More importantly, the CuQDA/IO@HA displayed biocompatibility and no obvious side-effect in normal organs. These results demonstrate the promising potential of integrating natural and metal ions into a nanomedicine that can provide precision medicine through synthetic lethality.

Injectable cell-based hydrogels allow surgical operation in a minimally invasive way for articular cartilage lesions but the chondrocytes in the injectable hydrogels are difficultly arrayed and fixed at the site of interest to repair the cartilage tissue. In this study, an injectable hyaluronic acid-polyacrylic acid (HA-pAA) hydrogel was first synthesized using hyaluronic acid-cyclodextrin (HA-CD) and polyacrylic acid-ferrocene (pAA-Fc) to provide cell-delivery and self-healing. To promote the cell fixation and alignment, porous poly(lactic

Due to the ongoing development of portable/mobile electronics, sources to power have received widespread attention. Compared to chemical batteries as power sources, triboelectric nanogenerators (TENGs) possess lots of advantages, including the ability to harvest energy via human motions, flexible structures, environment-friendliness, and long-life characteristics. Although many self-healable TENGs are reported, the achievement of a muscle-like elasticity and the ability to recover from inevitable damage under extreme conditions (such as a high/low temperature and/or humidity) remain a challenge. Herein, a "double-terminal aromatic disulfide" on a structure with zwitterions as branched chains is reported to engineer the high-efficient self-healable elastomer for application in a flexible TENG. The as-designed material exhibits a repeatable elastic recovery (at 250% elongation) and a self-healing efficiency with an ultimate tensile stress of 96% over 2 h, representing an improvement on previously reported disulfide-based elastomers. The elastomer can autonomously recover by 50% even at a subzero temperature of -30 °C within 24 h. The elastomer-based TENG, as a self-driven sensor for detecting human behavior, is demonstrated to exhibit stable outputs and self-healing in the temperature range of -30 to 60 °C, and so is expected to promote the development of self-powered electronics for next-generation human-machine communications.

Supercapacitors (SCs) are promising for powering mobile devices, electric vehicles and smart power grids due to their fast charge/discharge rate, high power capability and robust cycle stability. Nitrogen-doped porous carbons are great alternatives because they provide pseudocapacitance without losing their power rate. Nanoporous carbon derived from metal organic frameworks (MOFs) is an ideal precursor for preparing heteroatom-doped carbons due to their abundant nitrogen contents and incredible specific surface areas. However, severe aggregations and the leakage of nitrogen can occur during harsh carbonization. In this study, we used CoAl-LDH (cobalt aluminum layered double hydroxide) as an in-situ growth substrate, allowing Co-based MOF to uniformly grow onto the CoAl-LDH to form a sandwiched MOF/LDH/MOF structure. After acid etching, we obtained waffle-like nanoporous carbons (WNPC). WNPC exhibited high nitrogen and oxygen retention (7.5 wt% and 9.1 wt%) and a broad mesopores distribution with specific surface areas of 594 m2g&minus, 1, which promoted a sieving effect. This renders a specific capacitance of 300.7 F&middot, g&minus, 1 at 1 A&middot, 1 and the high retention (72%) of capacitance at 20 A&middot, 1, ensuring its use at high-rate supercapacitor electrodes. Finally, the WNPC symmetric supercapacitor reaches a superior specific energy of 27 W&middot, h&middot, kg&minus, 1 at a power of 500 W&middot, 1, and a good cycle stability (85% capacitance retention after 10,000 cycles).

The articular cartilage disorder at the junction mainly results from constantly repeated dynamic tension/compression effects with ageing and lack of intrinsic defect repairability. Therefore, the degradable piezoelectric scaffolds are very essential, which mimics the dynamic mechanical loading and optimizes the chondrocyte differentiation during the degradation. Here, a degradable aligned electrospun poly- L -lactic acid (PLLA) modified with graphene (rGO) and polydopamine (PDA) fibrous scaffolds with different orientations (0°, 90°) and surface morphologies (wrinkled and porous) was developed as a biocompatible and degradable piezoelectric scaffold with the self-powered tunable piezoelectricity to modulate cell behaviour and cell differentiation by tuning the degradation effect. The results show that the electrical output and mechanical properties of the composite fibrous scaffold can be improved by adding rGO and applying mechanical force along with the 90° orientation. With changing the degradation behavior, dynamic mechanical loading on the porous PLLA/rGO/PDA fibrous scaffold exhibits a significant increase in cell proliferation and secretion of extracellular matrix (ECM). More surprisingly, as extending the degradation periods to 21 days, a higher glycosaminoglycans (GAGs) synthesis was detected in prechondrogenic ATDC5 cells cultured on the degraded porous scaffold compared with that after 7 days’ culture. This indicated that long-term degradation favoured promoting cell differentiation of ATDC5 towards a chondrogenic phenotype due to dynamic mechanical loading, low-intensity electrical stimulation, and interconnected porous structural morphology. In contrast, on the wrinkled PLLA/rGO/PDA fibre with a high-intensity electrical stimulation, the ALP activity significantly increased after 21 days, inducing mineralization with the differentiation of ATDC5 into osteocytes. The modulation of the degraded environment and electrical stimulation of the piezoelectric scaffold offers an effective alternative to influence cell functions, significantly improving the ECM secretion and cell differentiation.