Bio-Inspired Low-Cost Fabrication of Stretchable, Adhesive, Transparent, and Multi-Functionalized Joint Wound Dressings

Elastic sac-shaped hydrogel dressing with responsive antibacterial and pro-healing in movable wounds via MOF activated ink spraying

In daily life, sports frequently cause skin injuries, particularly in movable parts such as joints. However, the frequent movement of joints can impede the proper fitting of dressings, resulting in re-tearing of the wound, an increased infection risk, and prolonged healing. Moreover, demand for skin wound dressings in movable parts has risen, as around 2.4 million joint surgeries are performed annually. Therefore, it is crucial to design an elastic wound dressing that can accommodate repeated joint movements and control wound infection responsively. In this study, a biomimetic hydrogel dressing was designed based on the inkjet behaviour of the elastic ink sac of cuttlefish through repeated extrusion. This dressing comprises a highly elastic polyether F127 diacrylate-based ink sac with micro-nozzles, along with antibacterial and pro-healing ink, metal-organic framework modified gelatin, possessing responsive release properties. With the movement rhythm, the super-elastic dressing perfectly conforms to the wounds in joints or other movable parts to absorb exudation and release therapeutic ink in response to the microenvironment to prevent infection. In conclusion, the biomimetic dressing demonstrates excellent mechanical properties with a deformation of approximately 400 %, and attains an antibacterial rate exceeding 95 %. Compared with the control group, collagen production increases by 2.6 times, and the wound healing speed is enhanced by over 20 %. Therefore, the application of the biomimetic dressing is anticipated to offer a novel approach for managing skin infection wounds in movable parts.

Shape-adaptive, deformable and adhesive hydrogels enable stable closure of long incision wounds

Effective closure of long incision wounds is crucial in clinical practice but remains challenging for existing bioadhesives due to the deformations of the long incisions. Herein, we propose a concept of shape-adaptive adhesion and achieve it by designing a class of shape-adaptive, deformable adhesive hydrogels (DAHs) for long incision wound closure. The design strategy is facile yet universally applicable, which involves aldehyde polysaccharides as adhesive primers and microgel-type gelators as building blocks. We demonstrate that the microgel-type gelators are responsible for the integration of a deformable matrix in situ, and aldehyde polysaccharides enhance the adhesive performance of the matrix at cost of a little deformability. Optimization of the flexibility of DAH network is effective in balancing the adhesive and deformable properties, thus developing DAHs featured with the adaptability to irregular shapes, robust adhesive properties, and appropriate deformability. As a result, DAHs achieve shape-adaptive adhesion by effectively bonding the long incision and deforming with it without failure. In vivo results clearly show that DAHs stably close the 4 cm-long incision wounds on the backs and the more dynamic incisions on the napes of rats. The shape-adaptive adhesion achieved by DAHs may provide an alternative way for long incision wound treatment. STATEMENT OF SIGNIFICANCE: Bioadhesive is emerging as an effective tool in clinical wound treatment. However, the closure of severe long incision wounds by currently available bioadhesives is still challenging. In this work, we proposed a concept of shape-adaptive adhesion and accordingly developed a bioadhesive building strategy for long incision wound closure. The strategy is universally applicable, which involves aldehyde polysaccharide as an adhesive primer and microgel-type gelators as building blocks. The results showed that the strategy is effective in developing bioadhesives (DAHs) that simultaneously possess shape-adaptive properties, robust adhesive properties and appropriate deformability, thus overcoming the limitations of most existing bioadhesives. With these features, DAHs successfully achieved shape-adaptive adhesion and stable closure of long incision wounds, providing an effective way for wound treatment.

A review on multifunctional calcium alginate fibers for full-time and multipurposed wound treatment: From fundamentals to advanced applications

Recent progress in wound healing has highlighted the need for more effective treatment strategies capable of addressing the complex biological and physiological challenges of wound repair. Traditional wound dressings often fail to address the complex and evolving needs of chronic, acute, and burn wounds, particularly in terms of promoting healing, preventing infection, and supporting tissue regeneration. In response to these challenges, calcium alginate fibers (CAFs) have emerged as promising materials, characterized by their exceptional structural properties and diverse biological functions, offering significant commercial potential for the development of advanced wound dressings and therapeutic solutions. Here, a brief review of the CAFs for promoting wound healing is presented, with specific discussions of the fundamental characteristics of CAFs and its feasibility to be applied for adjusting physiological and pathological processes involved in wound healing. Then, a comprehensive and in-depth depiction of emerging representative fabrication techniques for generating CAFs is categorized and reviewed. Moreover, emerging applications benefits from the CAFs are reviewed, highlighting the multifunctional roles and benefits of CAFs in facilitating wound repair. Finally, the challenges and perspectives for further advancing CAFs toward a more powerful and versatile therapeutic strategy are discussed, particularly regarding new opportunities in biomedical research and clinical applications.

Micro-Electro Nanofibrous Dressings Based on PVDF-AgNPs as Wound Healing Materials to Promote Healing in Active Areas

Purpose

The purpose of this study is to develop an innovative solution for chronic wounds in high-mobility areas, such as joints, where conventional treatments are hindered by passive healing mechanisms and the need for immobilization. By designing a micro-electro-Nanofiber dressing composed of piezoelectric polyvinylidene fluoride (PVDF) integrated with antimicrobial silver nanoparticles (AgNPs), this research aims to address the dual challenges of promoting effective wound healing and maintaining joint mobility.

Methods

Herein, we developed a novel micro-electro-Nanofiber dressing using electrospinning technology, incorporating polyvinylidene fluoride (PVDF) with silver nanoparticles (AgNPs). The optimized PVDF-AgNPs Nanofiber dressings exhibited strong piezoelectric effects suitable for joint wounds.

Results

In vitro experiments demonstrated that the dressing effectively promoted fibroblast migration and collagen synthesis. In vivo, the dressing exhibited a trend of rapid healing in infected wounds within 12 days while modulating macrophage differentiation toward the anti-inflammatory M2 phenotype. Additionally, the incorporation of antimicrobial nanosilver effectively controlled local infections, further facilitating the healing process.

Conclusion

To sum up, by harnessing the piezoelectric effect to stimulate endogenous healing mechanisms without restricting joint mobility, the developed PVDF-AgNPs Nanofiber dressings represent a transformative approach for the treatment of wounds in highly mobile body areas.

Motion-Accommodating Dual-Layer Hydrogel Dressing to Deliver Adipose-Derived Stem Cells to Wounds

BACKGROUND

Current dressing materials cannot secure a cell survival-promoting wound environment for stem cell delivery due to insufficient assimilation to skin motion. The authors developed a novel motion-accommodating dual-layer hydrogel dressing for stem cell delivery into such wounds.

METHODS

Dorsal hand skin movement was evaluated to determine the potential range of deformation for a dressing. The outer hydrogel (OH) was fabricated with an alginate-acrylamide double-network hydrogel with a covalently cross-linked elastomer coat. The tough adhesive consisted of a chitosan-based bridging polymer and coupling reagents. OH material properties and adhesiveness on porcine skin were measured. An oxidized alginate-based inner hydrogel (IH) containing human adipose-derived stem cells (ASCs) was evaluated for cell-supporting and cell-releasing properties. The OH's function as a secondary dressing, and dual-layer hydrogel cell delivery potential in wounds were assessed in a rodent model.

RESULTS

The dual-layer hydrogel consisted of OH and IH. The OH target range of deformation was up to 25% strain. The OH adhered to porcine skin, and showed significantly higher adhesion energy than common secondary dressings and endured 900 flexion-extension cycles without detachment. OH showed a similar moisture vapor transmission rate as moisture-retentive dressings. IH maintained embedded cell survival for three days with significant cell release on the contacting surface. OH showed less fibrotic wound healing than other secondary dressings in vivo. The dual-layer hydrogel successfully delivered ASCs into open wounds of nude mice (13 ± 3 cells/HPF).

CONCLUSIONS

The novel dual-layer hydrogel can accommodate patient movement and deliver ASCs into the wound bed by securing the wound microenvironment.

Sprayable Zwitterionic Antibacterial Hydrogel With High Mechanical Resilience and Robust Adhesion for Joint Wound Treatment

Wound healing in movable parts, including the joints and neck, remains a critical challenge due to frequent motions and poor flexibility of dressings, which may lead to mismatching of mechanical properties and poor fitting between dressings and wounds; thus, increasing the risk of bacterial infection. This study proposes a sprayable zwitterionic antibacterial hydrogel with outstanding flexibility and desirable adhesion. This hydrogel precursor is fabricated by combining zwitterionic sulfobetaine methacrylate (SBMA) with poly(sulfobetaine methacrylate-co-dopamine methacrylamide)-modified silver nanoparticles (PSBDA@AgNPs) through robust electrostatic interactions. About 150 s of exposure to UV light, the SBMA monomer polymerizes to form PSB chains entangled with PSBDA@AgNPs, transformed into a stable and adhesion PSB-PSB@Ag hydrogel at the wound site. The resulting hydrogel has adhesive strength (15-38 kPa), large tensile strain (>400%), suitable shape adaptation, and excellent mechanical resilience. Moreover, the hydrogel displays pH-responsive behavior; the acidic microenvironment at the infected wound sites prompts the hydrogel to rapidly release AgNPs and kill bacteria. Further, the healing effect of the hydrogel is demonstrated on the rat neck skin wound, showing improved wound closing rate due to reduced inflammation and enhanced angiogenesis. Overall, the sprayable zwitterionic antibacterial hydrogel has significant potential to promote joint skin wound healing.

Developing conductive hydrogels for biomedical applications

Conductive hydrogels have attracted copious attention owing to their grateful performances, such as similarity to biological tissues, compliance, conductivity and biocompatibility. A diversity of conductive hydrogels have been developed and showed versatile potentials in biomedical applications. In this review, we highlight the recent advances in conductive hydrogels, involving the various types and functionalities of conductive hydrogels as well as their applications in biomedical fields. Furthermore, the current challenges and the reasonable outlook of conductive hydrogels are also given. It is expected that this review will provide potential guidance for the advancement of next-generation conductive hydrogels.

An antibacterial nanoclay- and chitosan-based quad composite with controlled drug release for infected skin wound healing

Microbial infections of surgical sites and other wounds represent a major impediment for patients. Multifunctional low-cost dressings promoting tissue reparation while preventing infections are of great interest to medical professionals. Here, clay-based laponite nanodiscs (LAP) were loaded with the antibacterial drug kanamycin (KANA) before being embedded into a poly(lactic-co-glycolic acid) (PLGA) membrane and coated with the biopolymer chitosan (CS). Results indicated that these biocompatible materials combined the excellent capacity of LAP for controlled drug release with the mechanical robustness of PLGA and the antibacterial properties of CS as well as its hydrophilicity to form a composite highly suitable as an infection-preventing wound dressing. In vitro, PLGA/LAP/KANA/CS released drugs in a sustainable manner over 30 d, completely inhibited the growth of infectious bacteria, prompted the adhesion fibroblasts, and accelerated their proliferation 1.3 times. In vivo, the composite enabled the fast healing of infected full-thickness skin wounds with a 96.19 % contraction after 14 d. During the healing process, PLGA/LAP/KANA/CS stimulated re-epithelization, reduced inflammation, and promoted both angiogenesis and the formation of dense collagen fibers with an excellent final collagen volume ratio of 89.27 %. Thus, multifunctional PLGA/LAP/KANA/CS made of low-cost components demonstrated its potential for the treatment of infected skin wounds.

Green Synthesized Silver Nanoparticles Loaded in Polysaccharide Hydrogel Applied to Chronic Wound Healing in Mice Models

The prevalence of chronic wounds is increasing owing to the expanding population and the growing number of individuals suffering from diabetes. Such a chronic wound continues to be a significant healthcare burden for diabetic patients because it frequently carries a high chance of limb loss due to amputation and reduces survival as a result. Development of innovative wound dressing materials with the potential to stop bacterial infections and accelerate the process of tissue regeneration is needed to increase the effectiveness of diabetic wound healing. In the current study, a co-polymerization process based on a free radical reaction was used to create a hydrogel of polysaccharides blend graft acrylamide (PsB-g-Am). Starch, chitosan, and alginate make up the polysaccharides blend (PsB). The produced hydrogel's structure was characterized using FTIR spectroscopy. The antibacterial activities of silver nanoparticles synthesized through the green method using garlic bulb (Allium sativum) is reported. The silver nanoparticles' physical characteristics were examined using scanning electron microscopy, transmission electron microscopy analysis, and UV-visible spectroscopy and they were found to range in size from 50 to 100 nm. The agar well diffusion technique is used to investigate the antibacterial characteristics. Inclusion of silver nanoparticles in the hydrogels demonstrated concentration-dependent antibacterial behavior against Gram-negative Klebsiella pneumoniae and Gram-positive Staphylococcus aureus during antimicrobial testing of the hydrogels. When hydrogels were applied to diabetic mice, the system was examined for its healing abilities, and positive therapeutic results were obtained in as little as 14 days. Thus, it can be inferred that graft copolymer of chitosan-AgNPs hydrogels can promote healing in chronic wounds over time and can be utilized as an alternative to conventional therapies for chronic wounds (such as those brought on by diabetes) in mouse models.

Bioinspired Polymers: Transformative Applications in Biomedicine and Regenerative Medicine

Bioinspired polymers have emerged as a promising field in biomaterials research, offering innovative solutions for various applications in biomedical engineering. This manuscript provides an overview of the advancements and potential of bioinspired polymers in tissue engineering, regenerative medicine, and biomedicine. The manuscript discusses their role in enhancing mechanical properties, mimicking the extracellular matrix, incorporating hydrophobic particles for self-healing abilities, and improving stability. Additionally, it explores their applications in antibacterial properties, optical and sensing applications, cancer therapy, and wound healing. The manuscript emphasizes the significance of bioinspired polymers in expanding biomedical applications, addressing healthcare challenges, and improving outcomes. By highlighting these achievements, this manuscript highlights the transformative impact of bioinspired polymers in biomedical engineering and sets the stage for further research and development in the field.