The design and development of a smart bioadhesive hydrogel sealant with self-healing and excellent antibacterial activity to achieve high wound closure effectiveness and post-wound-closure care is highly desirable in clinical applications. In this work, a series of adhesive antioxidant antibacterial self-healing hydrogels with promising traits were designed through dual-dynamic-bond cross-linking among ferric iron (Fe), protocatechualdehyde (PA) containing catechol and aldehyde groups and quaternized chitosan (QCS) to enable the closure of skin incisions and promotion of methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing. The dual-dynamic-bond cross-linking of a pH-sensitive coordinate bond (catechol-Fe) and dynamic Schiff base bonds with reversible breakage and re-formation equips the hydrogel with excellent autonomous healing and on-demand dissolution or removal properties. Additionally, the hydrogel presents injectability, good biocompatibility and antibacterial activity, multifunctional adhesiveness, and hemostasis as well as NIR responsiveness. The in vivo evaluation in a rat skin incision model and infected full-thickness skin wound model revealed the high wound closure effectiveness and post-wound-closure care of the smart hydrogels, demonstrating its great potential in dealing with skin incisions and infected full-thickness skin wounds.

Dual-Dynamic-Bond Cross-Linked Antibacterial Adhesive Hydrogel Sealants with On-Demand Removability for Post-Wound-Closure and Infected Wound Healing.

Smart wound dressings for wound healing

Chitosan-based nanomaterials have attracted significant attention in the biomedical field because of their unique biodegradable, biocompatible, non-toxic, and antimicrobial nature. Multiple perspectives of the proposed antibacterial effect and mode of action of chitosan-based nanomaterials are reviewed. Chitosan is presented as an ideal biomaterial for antimicrobial wound dressings that can either be fabricated alone in its native form or upgraded and incorporated with antibiotics, metallic antimicrobial particles, natural compounds and extracts in order to increase the antimicrobial effect. Since chitosan and its derivatives can enhance drug permeability across the blood-brain barrier, they can be also used as effective brain drug delivery carriers. Some of the recent chitosan formulations for brain uptake of various drugs are presented. The use of chitosan and its derivatives in other biomedical applications is also briefly discussed.

https://www.mdpi.com/1420-3049/24/10/1960/pdf

Chitosan-based (Nano)materials for Novel Biomedical Applications.

Bacterial infection can cause chronic nonhealing wounds, which may be a great threat to public health. It is highly desirable to develop an injectable wound dressing hydrogel with multifunctions including self‐healing, remodeling, antibacterial, radical scavenging ability, and excellent photothermal properties to promote the regeneration of damaged tissues in clinical practice. In this work, dopamine‐modified gelatin (Gel‐DA) is employed for the first time as a biotemplate for enhancing the biomineralization ability of gelatin to synthesize dopamine‐modified gelatin@Ag nanoparticles (Gel‐DA@Ag NPs). Further, the prepared Gel‐DA@Ag NPs with antioxidant activity and near‐infrared (NIR) laser irradiation synergistic antibacterial behavior are fixed in the guar gum based hydrogels through the formation of borate/didiol bonds to possess remolding, injectable, and self‐healing performance. In addition, the multifunctional hydrogels can completely cover the irregular wound shape to prevent secondary injury. More importantly, these hydrogel platforms under NIR can significantly accelerate wound healing with more skin appendages like hair follicles and blood vessels appearing. Therefore, it is expected that these hydrogels can serve as competitive multifunctional dressings in biomedical field, including bacteria‐derived wound infection and other tissue repair related to reactive oxygen species overexpression.

Multifunctional Injectable Hydrogel Dressings for Effectively Accelerating Wound Healing: Enhancing Biomineralization Strategy

Chemical, physical, and biological coordination: An interplay between materials and enzymes as potential platforms for immobilization

A Macroporous Hydrogel Dressing with Enhanced Antibacterial and Anti-Inflammatory Capabilities for Accelerated Wound Healing

In this study, a novel biocompatible magnetic chitin nanofiber composite (MCNC) was developed as a support for enzyme immobilization, and the enzyme-immobilizing ability was elucidated using chymotrypsin (CT) as a model enzyme. Chitin nanofibers (CNFs) were prepared via 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation of chitin and then further modified with magnetic nanoparticles. Glutaraldehyde was used to cross-link the additional CT molecules and aggregate them onto the MCNCs. The CNFs were characterized by transmission electron microscopy, and Fourier transform infrared spectroscopy. The results showed that the CNFs were properly formed and that the CT molecules immobilized on the MCNCs presented excellent properties. After heating the composites at 60 °C for 3 h, the non-cross-linked and cross-linked immobilized CTs retained 51.6% and 70.7% of the initial activity, respectively, whereas the free CTs retained only 29.6% of the initial activity. In addition, non-cross-linked and cross-l...

Wei Wang

Papers

A Macroporous Hydrogel Dressing with Enhanced Antibacterial and Anti-Inflammatory Capabilities for Accelerated Wound Healing

Effective Enzyme Immobilization onto a Magnetic Chitin Nanofiber Composite