Publications by authors named "Yonggan Yan"

The controllable crosslinking between the constituting building blocks plays a key role in endowing the hydrogel with injectability through the formation of a uniform 3D interconnected network. Herein, a uniform-unsaturated crosslinking strategy has been devised to quickly construct injectable sodium alginate (SA) hydrogels. Under vigorous stirring, a moderate amount of metal ions can uniformly coordinate with the guluronate moieties of SA molecules, avoiding the locally excessive crosslinking and the loss of injectability caused by traditional dropping and soaking methods.

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Developing tunable underwater adhesives that possess tough adhesion in service and easy detachment when required remains challenging. Herein, a strategy is proposed to design a near infrared (NIR) photothermal-responsive underwater adhesive by incorporating MXene (TiCT)-based nanoparticles within isocyanate-modified polydimethylsiloxane (PDMS) polymer chains. The developed adhesive exhibits long-term and tough adhesion with an underwater adhesion strength reaching 5.

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Immediate and effective hemostatic treatments for complex bleeding wounds are an urgent clinical demand. Hemostatic materials with characteristics of adhesion, sealing, anti-infection, and concrescence promotion have drawn growing concerns. However, pure natural multifunctional hemostatic materials with in situ ultrafast self-gelation are rarely reported.

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Articular cartilages exhibit load-bearing capacity and durability due to their inhomogeneous structure. Inspired by this unique structure, a tough and inhomogeneous salt-hydrogel was developed by trapping sodium acetate (NaAc) crystals in polyacrylamide (PAM) polymer networks and then partially redissolving the NaAc crystals. The compressive and tensile stresses of the salt-hydrogel increase significantly by more than 20 times when oversaturated Ac and Na are introduced into the gel network.

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Hydrogels containing hydrophobic materials have attracted great attention for their potential applications in drug delivery and biosensors. This work presents a kneading-dough-inspired method for dispersing hydrophobic particles (HPs) into water. The kneading process can quickly mix HPs with polyethyleneimine (PEI) polymer solution to form "dough", which facilitates the formation of stable suspensions in aqueous solutions.

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Three-dimensional (3D) nerve cell models have been widely developed to understand the mechanisms and discover treatment methods of ischemic stroke and neurodegenerative disease. However, there is a contradiction in the production of 3D models that they should possess high modulus to ensure mechanical stability while low modulus to provide mechanical stimuli for nerve cells. In addition, it is challenging to maintain the long-term viability of 3D models when lacking vascular structures.

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Bacterial infection often leads to inflammatory responses and delays wound healing. Chitosan (CS)-based composite hydrogels can hold desirable mechanical properties and maintain excellent antibacterial abilities, and thus may be promising as wound dressings. Although CS-based hydrogels have been widely studied on the antibacterial and wound-healing abilities, their immunomodulatory abilities were rarely evaluated.

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Endovascular surgery is a high-risk operation with limited vision and intractable guidewires. At present, endovascular surgery robot (ESR) systems based on force feedback liberates surgeons' operation skills, but it lacks the ability to combine force perception with vision. In this study, a deep learning-based guidewire-compliant control method (GCCM) is proposed, which guides the robot to avoid surgical risks and improve the efficiency of guidewire operation.

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Living bodies are made of numerous bio-sensors and actuators for perceiving external stimuli and making movement. Hydrogels have been considered as ideal candidates for manufacturing bio-sensors and actuators because of their excellent biocompatibility, similar mechanical and electrical properties to that of living organs. The key point of manufacturing hydrogel sensors/actuators is that the materials should not only possess excellent mechanical and electrical properties but also form effective interfacial connections with various substrates.

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Hypothesis: The drug release efficiency of microneedle is usually slower than that of oral delivery or hypodermic injection, which severely restricts its widespread use. Herein, a FeO-loaded photothermal microneedle (FeO@MN) patch is developed for controlled drug delivery. Under near infrared (NIR) irradiation, the drug loaded on FeO@MN can be quickly released, achieving an enhanced drug release efficiency.

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Mutations of H-Ras, a member of the RAS family, are preferentially found in cutaneous squamous cell carcinomas (SCCs). H-Ras has been reported to induce autophagy, which plays an essential role in tissue homeostasis in multiple types of cancer cells and in fibroblasts, however, the potential role of H-Ras in regulating autophagy in human keratinocytes has not been reported. In this study, we found that the stable expression of the G12V mutant of H-RAS (H-Ras ) induced autophagy in human keratinocytes, and interestingly, the induction of autophagy was strongly blocked by inhibiting the calcineurin/nuclear factor of activated T cells (NFAT) pathway with either a calcineurin inhibitor (Cyclosporin A) or a NFAT inhibitor (VIVIT), or by the small interfering RNA (siRNA) mediated knockdown of calcineurin B1 or NFATc1 , as well as To characterize the role of the calcineurin/NFAT pathway in H-Ras induced autophagy, we found that H-Ras promoted the nuclear translocation of NFATc1, an indication of the activation of the calcineurin/NFAT pathway, in human keratinocytes.

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p53, the major tumor suppressor, is frequently mutated in many cancers, and up to 84% of human melanomas harbor wild-type p53, which is considered to be an ideal target for melanoma therapy. Here, we evaluated the antitumor activity of a carbazole derivative, 9-ethyl-9H-carbazole-3-carbaldehyde (ECCA), on melanoma cells. ECCA had a selectively strong inhibitory activity against the growth of BRAF-mutated and BRAF-wild-type melanoma cells but had little effect on normal human primary melanocytes.

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Hypothesis: Ice accretion is a challenging issue for various residential activities and industrial facilities. However, most of the current anti/de-icing coatings fail to maintain their properties when subject to frequent mechanical wear, and their limited functionality (either anti-icing or de-icing individually) cannot meet the requirement of all-weather utilization.

Experiments: Herein, a multifunctional superhydrophobic coating is prepared by compositing ferroferric oxide nanoparticles (FeO NPs) with fluorinated epoxy resin via an inverse infiltration process.

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Article Synopsis
  • Functional hydrogels are being explored as wet adhesives for biomedical applications, but options for use in freezing conditions have been limited.
  • A new glycerol-ionic hydrogel has been developed that can withstand temperatures below -50 °C, is ultra-stretchable, and exhibits rapid self-healing properties.
  • This hydrogel demonstrates strong reversible adhesion to iron substrates, maintaining significant adhesion strength at low temperatures while also revealing changes in failure types based on temperature shifts.
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For the wide application of nanoparticles (NPs) (e.g., in nanotribology), it is of fundamental and practical importance to understand the self-assembly and lubrication behavior of confined NPs.

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