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Bacterial infections can significantly impede wound healing and pose a serious threat to the patient's life. The excessive use of antibiotics to combat bacterial infections has led to the emergence of multi-drug-resistant bacteria. Therefore, there is a pressing need for alternative approaches, such as photothermal therapy (PTT), to address this issue. In this study, for the first time, CuS NPs with photothermal properties were synthesized using sericin as a biological template, named CuS@Ser NPs. This method is simple, green, and does not produce toxic and harmful by-products. These nanoparticles were incorporated into a mixture (XK) of xanthan gum and konjac glucomannan (KGM) to obtain XK/CuS NPs composite hydrogel, which could overcome the limitations of current wound dressings. The composite hydrogel exhibited excellent mechanical flexibility, photothermal response, and biocompatibility. It also demonstrated potent antibacterial properties against both Gram-positive and negative bacteria via antibacterial experiments and accelerated wound healing in animal models. Additionally, it is proved that the hydrogel promoted tissue regeneration by stimulating collagen deposition, angiogenesis, and reducing inflammation. In summary, the XK/CuS NPs composite hydrogel presents a promising alternative for the clinical management of infected wounds, offering a new approach to promote infected wound healing., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Tumor local chemotherapy employing injectable hydrogel reservoirs is a promising platform to achieve precise drug administration. However, balanced injectability, pH-responsiveness and long-term hydrolysis resistance of self-healing hydrogels remain appealing challenges. Herein, a modular preassembly strategy combining host-guest interactions with dynamic acylhydrazone bonds, was exploited to fabricate injectable cellulose-based hydrogels (CAAs) dressed with self-healing properties, pH-responsiveness and hydrolytic degradation resistance. Attributed to the host-guest interaction between β-cyclodextrin (CD) and 1-adamantane (AD), the hydrogels exhibited injectability, self-healing properties (healing efficiency of 97.5%) and rapid recovery (< 10 min) without external stimuli in physiological environment. Moreover, the hydrogels equipped with dynamic acylhydrazone linkages underwent slow hydrolytic degradation (> 30 days) and pH-responsive behavior, endowing the hydrogels with precise spatiotemporal drug release administration. The in vivo application of CAA as a carrier was studied using doxorubicin (DOX) model drug, and the results shows that using CAA as DOX carrier not only greatly enhances the anti-tumor efficacy of DOX, but also reduced the side effects of DOX. STATEMENT OF SIGNIFICANCE: With the preassemble approach combining host-guest interactions with dynamic acylhydrazone bonds, this work demonstrated a multi-functional self-healing hydrogel as drug carrier developed by using natural polysaccharides, which offers a new avenue for the high-value utilization of biomass. The strategy demonstrated in the present work may also supply a pathway for the preparation and regulation of hydrogels as intelligent biomedicine materials., Competing Interests: Declaration of Competing Interest The authors declare no known conflict of interest., (Copyright © 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

To meet the rising demand of injectable hydrogels with self-healing, robustness and biocompatibility for biomedical engineering, the reversible ketoester-type acylhydrazone linkages was used for the fabrication of novel cellulose-based hydrogel. The ketoester-type acylhydrazone bond exchanged rapidly, endowing the hydrogels with highly efficient self-healing performance without any external stimuli under physiological environment, which was hardly achieved with the widely used arylhydrozone bond. The dynamic hydrogels exhibited tunable mechanical property, pH responsiveness, injectability and biocompatibility, demonstrating immense applications prospect for various biomedicines, such as drug and cell delivery. The pH-responsive controlled release of model drug doxorubicin (DOX) loaded in the hydrogel was demonstrated. In addition, benefitting from the excellent biocompatibility and the reversible ketoester-type acylhydrazone bonds, cells were encapsulated in the hydrogels as 3D carrier. The covalent adaptable network intensified injectability of cell-laden hydrogels and improved the long-lasting viability for cell culture, showing great potential in the biomedical field., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

To meet the demands of various therapeutic tasks, injectable hydrogels with tunable mechanical properties and degradability are highly desired. Herein, we developed an injectable chitin hydrogel system with well-manipulated mechanical properties and degradability through dynamic acylhydrazone crosslinking catalyzed by 4-amino-DL-phenylalanine (Phe-NH 2 ). The mechanical properties and degradability of the hydrogels could be easily adjusted by varying the solid content, while their gelation time could be maintained at a constant level (∼130 s) by altering Phe-NH 2 content, thereby ensuring the good injectability of hydrogels. Moreover, the chitin hydrogels showed excellent self-healing capacity with a healing efficiency up to 95 %. Owing to their superior biocompatibility and biodegradability, the chitin hydrogels could support the proliferation and multi-potent differentiations of rat bone marrow-derived stem cells, serving as a beneficial 3D scaffold for stem cell encapsulation and delivery. This work provides a promising injectable delivery vehicle of therapeutic drugs or cells for tissue regenerative medicine., (Copyright © 2020. Published by Elsevier Ltd.)

To meet the urgent requirement in complex wound treatment, the injectable self‐healing biocompatible hydrogel with tunable mechanical properties, adhesion, on‐demanding removability, antibacterial properties, and hemostasis is designed. For the first time, hydrogels are fabricated through dynamic enamine bonds among dodecane grafted quaternized chitosan (DQCS) and ketone group functionalized polyvinyl alcohol (PVA‐Ket) to achieve efficient wound closure. Owing to the dynamic enamine bond, the hydrogel exhibits self‐healing, injectability and suitable mechanical properties. It can be easily injected into wound, adhere tightly, and bear deformation damage. Dodecyl groups and quaternary amine groups endow the biocompatible hydrogels outstanding antibacterial feature, hemostatic performance, and tissue adhesiveness (40.05 ± 3.21 kPa), which greatly facilitate the wound healing process. Owing to interaction between the amino acid and PVA‐Ket, the hydrogel exhibits painless on‐demand dissolution behavior, causing uninjurious separation from wound sites. Furthermore, in vivo study demonstrates that the hydrogel promotes wound healing by upregulating growth factors, alleviating the inflammation and promoting angiogenesis, collagen deposition, and the growth of granulation tissue, leading to a better curative effect than the commercial gauze and Atrauman. Ag in infected and uninfected wounds. Thus, the multifunctional dynamic enamine‐based hydrogel with on‐demand removability has great potential in clinical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel hydrogel dressing with excellent biocompatibility and photothermal antibacterial properties was prepared. • The composite hydrogel dressing exhibits excellent and stable compression elasticity. • Hydrogel dressing shows rapid hemostasis and promotes the healing of infected wounds. • Hydrogel dressing promoted angiogenesis, reduced inflammation, as well as greatly facilitated epithelialization and collagen deposition. Skin wounds accompanied by massive bleeding and bacterial infection can be life-threatening and pose a significant challenge to clinical wound management. Herein, we prepared gellan gum/sericin hydrogels containing PDA-encapsulated halloysite nanotubes (halloysite@polydopamine) to achieve fast hemostasis and photothermally antibacterial effects. The morphology and compressive properties of the composite hydrogels were characterized, and the biocompatibility was investigated by hemocompatibility and cytocompatibility tests. The hemostatic properties were further evaluated in the rat liver hemorrhage and tail amputation model. The mechanical performance (compressive strength 353.2 KPa) and the hemostatic effect (30.33 ± 3.68 s in the liver injury model and 28.33 ± 2.35 s in the caudal amputation model) of the composite hydrogel were improved due to the introduction of halloysite@polydopamine. In addition, the composite hydrogel rapidly heated under 808 nm near-infrared (NIR) light irradiation, making the hydrogel extremely effective against E. coli and S. aureus. Furthermore, the wound closure rate, granulation tissue thickness, collagen deposition, and expression of inflammation-associated cytokines (CD68) and angiogenesis-associated cytokines (CD31) were investigated in a rat full-thickness skin defect model infected with S. aureus. All results showed that this multifunctional hydrogel provided better healing effects, suggesting that the composite hydrogel has become a promising alternative for infected wound repair. [ABSTRACT FROM AUTHOR]

Currently, adhesive hydrogels have shown promising effect in chronic diabetic wound repair. However, there are issues and challenges in treating diabetic wounds due to inadequate wet adhesion, unable to fill irregular and deep wounds, and oxidative stress. Herein, a mussel-inspired naturally hydrogel dressing with rapid shape adaptability, wet adhesion and antioxidant abilities for irregular, deep and frequently movement diabetic wounds repair was constructed by comprising catechol modified carboxymethyl cellulose (CMC-DA) and tannic acid. Benefiting from the reversible hydrogen bonding, the resulting hydrogels exhibited injectability, remarkable self-healing ability, rapid shape adaptability and strong tissue adhesion (45.9 kPa), thereby contributing to self-adaptive irregular-shaped wounds or moving joint parts. Especially, the adhesion strength of the hydrogel on wet tissue still remained at 14.9 kPa. Besides, the hydrogels could be easily detached from the skin by ice-cooling that avoided secondary damage caused by dressing change. Remarkably, the hydrogels possessed excellent antioxidant, satisfactory biocompatibility, efficient hemostasis and antibacterial properties. The in vivo evaluation further demonstrated that the hydrogel possessed considerable wound-healing promotion effect by regulating diabetic microenvironment, attributed to that the hydrogel could significantly reduce inflammatory response, alleviate oxidative stress and regulate neovascularization. Overall, this biosafe adhesive hydrogel had great potentials for diabetic wound management. This hydrogel dressing was fabricated via facile physical blending of catechol modified carboxymethyl cellulose and TA. The resulting hydrogels showed good injectability, rapid self-healing property, excellent shape adaptivity, antioxidant properties strong adhesion properties even in wet environment for deep and irregular wounds. Importantly, the hydrogels displayed antibacterial, antioxidant and hemostatic properties, and have great effects for diabetic wound repair. [Display omitted] [ABSTRACT FROM AUTHOR]