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Real‐time monitoring of respiration plays a very important role in human health assessment, especially in monitoring and analyzing respiration during exercise and sleep. However, traditional humidity sensors still have problems in flexibility, sensitivity, and durability, so there is an urgent need to develop humidity sensors with high sensitivity, stretchability, and environmental resistance as respiratory monitoring applications. Here, based on the double network hydrogel structure of polyvinyl alcohol and polyacrylamide, a highly sensitive, highly stretchable, and environmentally stable organic hydrogel humidity sensor has been manufactured by using the synergistic effect of lithium chloride and MXene. The hydrogel humidity sensor shows rapid response in the humidity range of 40–85% RH, and has a high sensitivity of −103.4%/% RH. In addition, it exhibits more than 3000% mechanical strain and excellent environmental resistance, which is attributed to the chemical cross‐linking in the hydrogel network and the synergistic effect of multiple hydroxyl groups in glycerol forming rich hydrogen bonds with water and polymer chains. The hydrogel humidity sensor is used for real‐time monitoring of breathing and sleep processes. This work provides a new strategy for preparing high‐performance, extensibility, and environmental stability hydrogel‐based sensors for respiratory monitoring. [ABSTRACT FROM AUTHOR]

The treatment of intervertebral disc degeneration (IVDD) using bone marrow mesenchymal stem cell‐derived exosomes has shown success in alleviating inflammation and restoring the extracellular matrix (ECM), however, challenges persist due to the deficiency in mechanical support and controlled release. Herein, a carbon‐carbon double bond modified keratin (KeMA) is synthesized by 2‐isocyanatoethyl modification for exosomes wrapping. This injectable KeMA hydrogel, initiated by a biocompatible glucose/ glucose oxidase/ horse radish peroxidase enzymatic cascade reaction with acetylacetone and N‐vinylpyrrolidone, displayed rapid gelation, resembling nucleus pulposus (NP) elasticity, and excellent cytocompatibility. In vitro studies showcased that the exosomes‐loaded KeMA hydrogel (Exo@KeMA) enhanced exosome release kinetics, suppressed inflammation, fostered extracellular matrix (ECM) regeneration, and reinstated NP biomechanics. RNA‐seq analysis indicated Exo@KeMA's effects involved PI3K‐Akt signaling for matrix regeneration and NF‐κB signaling inhibition for anti‐inflammation. In vivo IVDD rat models demonstrated Exo@KeMA attenuated inflammation, maintained NP water content, preserved disc height, and promoted structural regeneration. This research introduces an injectable KeMA hydrogel as a promising therapy for IVDD, by facilitating biomechanics restoration, anti‐inflammatory response, and ECM regeneration. [ABSTRACT FROM AUTHOR]

There is an unmet need for easy‐to‐visualize drug carriers that can deliver therapeutic cargoes deep into solid tumors. Herein, we report the preparation of ultrasmall luminescent imine‐based lanthanide nanocages, Eu60 and Tb60 (collectively Ln60), designed to encapsulate anticancer chemotherapeutics for tumor therapy. The as‐prepared nanocages possess large cavities suitable for the encapsulation of doxorubicin (DOX), yielding DOX@Ln60 nanocages with diameters around 5 nm. DOX@Ln60 are efficiently internalized by breast cancer cells, allowing the cells to be visualized via the intrinsic luminescent property of Ln(III). Once internalized, the acidic intracellular microenvironment promotes imine bond cleavage and the release of the loaded DOX. DOX@Ln60 inhibits DNA replication and triggers tumor cell apoptosis. In a murine triple negative breast cancer (TNBC) model, DOX@Ln60 was found to inhibit tumor growth with negligible side effects on normal tissues. It proved more effective than various controls, including DOX and Ln60. The present nanocages thus point the way to the development of precise nanomedicines for tumor imaging and therapy. [ABSTRACT FROM AUTHOR]

Conductive hydrogels (CHs) for flexible bioelectronic devices have raised great attention due to their tunable mechanical performances, adhesion, anti‐swelling, and biocompatibility. This review summarizes the current development of conductive hydrogel‐based flexible bioelectronic devices in the aspect of classifications and applications. Firstly, the conductive hydrogels are classified into two kinds according to the types of conductivity: ionic conductive hydrogels and electronic conductive hydrogels (hydrogel based on pure conductive materials, introducing conductive micro/nano‐materials). Secondly, the applications of conductive hydrogels for bioelectronic device, like wearable devices (strain sensor, body fluid detector, serviced in extreme environment), tissue engineering (skin, heart, nerve, muscle), and other applications (bionic robot, cancer treatment), are highly illustrated. Finally, a depth outlook is given, which aims to promote the development of this field in the future. [ABSTRACT FROM AUTHOR]

Finding a suitable biomaterial for scaffolding in cartilage tissue engineering has proved to be far from trivial. Nonetheless, it is clear that biomimetic approaches based on gelatin (Gel) and hyaluronic acid (HA) have particular promise. Herein, a set of formulations consisting of photo-polymerizable Gel; photo-polymerizable HA, and allogenic decellularized cartilage matrix (DCM), is synthesized and characterized. The novelty of this study lies particularly in the choice of DCM, which was harvested from an abnormal porcine with α-1,3-galactose gene knockout. The hybrid hydrogels were prepared and studied extensively, by spectroscopic methods, for their capacity to imbibe water, for their behavior under compression, and to characterize microstructure. Subsequently, the effects of the hydrogels on contacting cells (in vitro) were studied, i.e., cytotoxicity, morphology, and differentiation through monitoring the specific markers ACAN, Sox9, Coll2, and Col2α1, hypertrophy through monitoring the specific markers alkaline phosphatase (ALP) and Col 10A1. In vivo performance of the hydrogels was assessed in a rat knee cartilage defect model. The new data expand our understanding of hydrogels built of Gel and HA, since they reveal that a significant augmenting role can be played by DCM. The data strongly suggest that further experimentation in larger cartilage-defect animal models is worthwhile and has potential utility for tissue engineering and regenerative medicine. [ABSTRACT FROM AUTHOR]