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With the aging and obesity era, the increasing incidence of diabetes and diabetic complications, especially the non‐healing wounds, imposes a serious economic burden on both patients and society. The complex microenvironments, including hyperglycemia, bacterial infection, ischemia, and nerve damage, lead to the prolonged inflammation and proliferation phase of diabetic wounds. Mesenchymal stem cell‐derived small extracellular vesicles (MSC‐sEVs), which contain a rich variety of therapeutic molecules, have been chased for decades because of their potential roles in cellular communication, tissue regeneration, and drug delivery. As powerful tools for the controlled‐sustained release of sEVs, biocompatible hydrogels have been applied in a wide range of biomedical applications. Herein, we first summarize the pathological features of diabetic wounds, such as angiopathy, neuropathy, and immune cell dysfunction. Then, we discuss the biological properties, therapeutic performance, and stability of pure MSC‐sEVs. After that, we discuss the components, application patterns, and responsiveness of hydrogels. Next, we discuss the loading avenues of MSC‐sEVs into hydrogel, the release behaviors of sEVs from hydrogels, and the influence of the crosslinking method on the hydrogel‐sEV composites. Finally, we provide an overview of the current applications of hydrogels loaded with MSC‐sEVs as a novel cell‐free tissue engineering system in managing diabetic wounds and propose the critical unsolved issues. This review is expected to provide meaningful guidance for developing a novel cell‐free tissue engineering system for diabetic wound management. [ABSTRACT FROM AUTHOR]

Excessive exudate secreted from diabetic wounds often results in skin overhydration, severe infections, and secondary damage upon dressing changes. However, conventional wound dressings are difficult to synchronously realize the non‐maceration of wound sites and rapid exudate transport due to their random porous structure. Herein, a self‐pumping Janus hydrogel with aligned channels (JHA) composed of hydrophilic poly (ethylene glycol) diacrylate (PEGDA) hydrogel layer and hydrophobic polyurethane (PU)/graphene oxide (GO)/polytetrafluoroethylene (PTFE) layer is designed to rapidly export exudate and accelerate diabetic wound healing. In the design, the ice‐templating process endows the hydrophilic hydrogel layer with superior liquid transport ability and mechanical strength due to the formation of aligned channel structure. The hydrophobic layer with controlled thickness functions as an effective barrier to prevent exudate from wetting the skin surface. Experiments in diabetic rat model show that JHA can significantly promote re‐epithelialization and collagen deposition, shorten the inflammation phase, and accelerate wound healing. This unique JHA dressing may have great potential for real‐life usage in clinical patients. [ABSTRACT FROM AUTHOR]

Surface adhesion has a great contradiction in high strength and good reversibility given their mutually exclusive requirements of fixed crosslinked networks and dynamic chain motion. Herein, we demonstrate a supramolecular organoplatinum(II) adhesive system regulated by intermolecular PtII⋅⋅⋅PtII interactions that can simultaneously achieve high‐strength and excellent reversible adhesion to various substrates. Upon alternating temperature, the assembly of suitably substituted organoplatinum(II) molecules can switch between well‐ordered and disordered states via tuning PtII⋅⋅⋅PtII interactions, resulting in stable reversible adhesion even after 100 cycles with a robust strength of ≈1.25 MPa and a large on‐off ratio of ≈25. Along with the switch of PtII⋅⋅⋅PtII contacts, the surface adhesion of organoplatinum(II) adhesives can be monitored by their changes in electrical signals. This study will open up new inspirations for developing high‐performance reversible adhesives. [ABSTRACT FROM AUTHOR]

Nanoparticle aggregation for constructing functional materials has shown enormous advantages in various applications. Most efforts focused on ordered nanoparticle aggregation for specific functions but were often limited to irreversible aggregation processes due to the thermodynamic equilibrium. Herein, we report a reversible disordered aggregation of SiO2‐PNIPAAm nanoparticles (SPNPs) through thermo‐responsive jamming, obtaining smart liquid–solid switchable materials. The smart materials can display a switch between liquid‐like state and solid‐like state responding to a temperature change. This unique macroscopic behavior originates from the reversible disordered aggregation modulated by temperature‐dependent hydrophobic interactions among the SPNPs. Notably, the materials at the solid‐like state show anti‐impact properties and can withstand the impact of a steel sphere with a speed of 328 cm s−1. We envision that this finding offers inspiration to design smart liquid–solid switchable materials for impact protection. [ABSTRACT FROM AUTHOR]

In nature, many organisms are able to accommodate a complex living environment by developing biological wet adhesive surfaces with unique functions such as fixation and predation. Significantly, most of these outstanding functions originate from the specialized micro/nanostructures and/or chemical components of these natural organisms. To design artificial surfaces with remarkable wet adhesive properties, the underlying mechanisms of the fascinating adhesion phenomena are further explored and summarized to provide continuous inspiration. Herein, a systematic overview of biological wet adhesive surfaces and the corresponding artificial counterparts from the perspective of surface micro/nanostructures is provided. First, the research progress of the typical biological wet adhesive surfaces such as the octopus, tree frogs, and mayfly larvae is introduced. Then, the fundamental models of surface adhesion in natural organisms and the commonly used instruments for measuring adhesion force are discussed. Later, the corresponding artificial wet adhesive surfaces inspired by these representative organisms are highlighted. After that, the typical methods for fabricating these surfaces are briefly introduced. Finally, future challenges and opportunities to develop bioinspired multiscaled wet adhesive surfaces with controlled adhesion are presented. [ABSTRACT FROM AUTHOR]

Cell-based microarrays are widely used in the fields of drug discovery and toxicology. Precise gradient generation and automated drug feeding are essential for high-throughput screening of live cells in tiny droplets. However, most existing technologies either require sophisticated robotic equipment or cause mechanical/physiological interference with cells. Here, a heterogeneous organohydrogel is presented for automated gradient drug feeding, while ensuring minimal interference with cells. The heterogeneous organohydrogel comprises three crucial components. The bottom surface can automatically generate gradients functioning as a gradient generator, the organohydrogel bulk allows unidirectional transport of drugs without backflow, and the top surface with hydrophilic arrays can firmly anchor the cell-based droplet array to evaluate the concentration-dependent bioeffects of drugs accurately. Such a unique structure enables universal screening of different cell types and drugs dissolved in different solvents, requiring neither additional accessories nor arduous drug functionalization. The heterogeneous organohydrogel with unprecedented automation and non-interference possesses the enormous potential to be a next-generation platform for drug screening., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Surface adhesion has a great contradiction in high strength and good reversibility given their mutually exclusive requirements of fixed crosslinked networks and dynamic chain motion. Herein, we demonstrate a supramolecular organoplatinum(II) adhesive system regulated by intermolecular Pt II ⋅⋅⋅Pt II interactions that can simultaneously achieve high-strength and excellent reversible adhesion to various substrates. Upon alternating temperature, the assembly of suitably substituted organoplatinum(II) molecules can switch between well-ordered and disordered states via tuning Pt II ⋅⋅⋅Pt II interactions, resulting in stable reversible adhesion even after 100 cycles with a robust strength of ≈1.25 MPa and a large on-off ratio of ≈25. Along with the switch of Pt II ⋅⋅⋅Pt II contacts, the surface adhesion of organoplatinum(II) adhesives can be monitored by their changes in electrical signals. This study will open up new inspirations for developing high-performance reversible adhesives., (© 2022 Wiley-VCH GmbH.)

Underwater superoleophobic surfaces featuring anti-oil-fouling properties are of great significance in widespread fields. However, their complicated engineering process and weak interfacial adhesion strength with underlying substrates severely hamper these ideal surfaces toward practical applications. Here, a moss-inspired sticky-slippy skin composed of layered organohydrogel is reported through a one-step wetting-enabled-transfer (WET) strategy, which unprecedentedly integrates robust inherent adhesion with durable anti-oil-fouling properties. The sticky organogel layer can be simply attached to various substrates, from metals and plastics to glass, independent of any surface pretreatment. The slippy hydrogel layer enables stable underwater superoleophobicity and ultralow oil adhesion for diverse kinds of oils. The sticky-slippy skin features outstanding comprehensive properties including easy-pasting, anti-swelling/anti-bending, compatibility with commercial adhesives, acid/alkali resistance, environmental friendliness, and substrate universality. The design strategy with integrated functions provides a clue to accelerate the development of bioinspired multifunctional interfacial materials toward real-world applications., (© 2022 Wiley-VCH GmbH.)