Zinc ions and ciprofloxacin-encapsulated chitosan/poly(ɛ-caprolactone) composite nanofibers promote wound healing via enhanced antibacterial and immunomodulatory

Imino-quaternized chitosan/chitosan nanofibers loaded with norfloxacin as potential bandages for wound healing

Due to the critical need for effective wound dressings for the management of burn injuries, this paper focuses on addressing key gaps in infection prevention and control. The study aims to develop advanced nanofibrous dressings based on quaternized chitosan/chitosan, loaded with norfloxacin and modified with 2-formylphenylboronic acid to enhance antimicrobial and antioxidant activity and promote healing. The materials combine beneficial properties of chitosan/quaternized chitosan, such as biocompatibility, biodegradability, and antimicrobial activity. The characterization was performed from structural (NMR, FTIR, UV-Vis spectroscopy and thermogravimetric analysis), morphological (SEM, water vapor sorption) and supramolecular points of view (X-Ray Diffraction and Polarized Microscopy). Essential properties for wound dressings were evaluated and proved excellent performances, such as Young's modulus up to 1250 MPa, swelling capacity till 6 g/g, radical scavenging activity of 70 % and enzymatic degradability till 53 % in 21 days. The fibers presented antibacterial properties, reflected by high inhibition zones against Escherichia coli (40 mm) and Staphylococcus aureus (34 mm) and antifungal activity against Candida glabrata (15 mm). Preliminary studies demonstrated the in vitro safety of the materials on Human Gingival Fibroblasts, while in vivo experiments on Wistar rats confirmed the biocompatibility of the materials, emphasizing their potential as effective wound dressings for burns.

Recent advances in structural and functional design of electrospun nanofibers for wound healing

The global prevalence of acute and chronic wounds has surged, escalating healthcare burdens and necessitating advanced therapeutic strategies for effective wound management. Electrospun nanofibers have emerged as promising biomimetic platforms for tissue engineering and drug delivery, due to their structural resemblance to the native extracellular matrix (ECM), high porosity, and tunable surface-to-volume ratio. Recent advances in structural design have expanded their applications from conventional two-dimensional (2D) wound dressings to multifunctional three-dimensional (3D) architectures, enabling enhanced mechanical adaptability, bioactive molecule loading, and spatiotemporal control over wound microenvironments. These innovations leverage nanofibers' customizable topography and composition to recapitulate critical ECM cues, thereby fostering cell proliferation, angiogenesis, and immunomodulation during tissue regeneration. This review systematically evaluates cutting-edge strategies focusing on optimizing 2D arrangements and the structural design of multilayered and functionally patterned 3D electrospun nanofibers in wound healing applications. We further present the advantages and limitations of various nanofiber structures, along with the key challenges and future directions for advancing electrospun nanofibers specifically designed for enhanced wound healing.

Zinc sulfate gel reshapes the wound microenvironment to promote full-thickness wound healing in mice

Delayed healing of skin wounds significantly impacts human life, Zinc plays a pivotal role in human growth, the immune system, and various cellular processes. Previous studies have demonstrated that zinc supplementation or topical zinc ion therapy can accelerate wound healing in cases of skin injury. Zinc deficiency has been linked to delayed wound healing, but the role it plays remains to be elucidated. In this study, we report the preparation of zinc sulfate gel to promote wound healing by treating inflammation, antioxidant effects, and angiogenesis. We demonstrated the efficacy of zinc sulfate gel in wound healing in a mouse model of full-thickness skin excision, spared the anti-inflammatory and antioxidant capabilities of zinc ions. Furthermore, Zinc sulfate gel can stimulate tissue to enter the proliferative phase by regulating macrophage polarization, thereby accelerating collagen deposition, granulation tissue formation, and extracellular matrix production and remodeling. In conclusion, zinc ion gel provides a promising strategy for skin wounds regeneration.

Antimicrobial Zn2+-Carboxymethyl Chitosan Cryogel for Controlled Loading and Release of Ciprofloxacin via Coordination Bonds

The local application of broad-spectrum antibiotics via polymeric drug delivery systems is a promising alternative to their systemic administration in wound healing, prevention and treatment of infections associated with surgical implants. However, low and poorly controlled loading efficiency and 100% burst release are common problems for the materials with weak physical interaction between antibiotics and polymeric matrices. Here, we report a new multifunctional carboxymethyl chitosan (CMC) cryogel, which efficiently prevents bacterial adhesion to the surface, kills bacteria in the solution via controlled release of ciprofloxacin (CIP), and promotes fibroblast proliferation. The suggested approach is based on CIP loading to Zn2+-chelated CMC cryogel via the ligand exchange reaction. We have shown that, due to the strong binding of Zn2+ to CMC, the antibacterial effect and toxicity to fibroblasts of CMC-Zn-CIP cryogels were mainly determined by the content of loaded CIP, which can be precisely controlled via Zn2+ content in cryogel. CMC cryogels containing 20 mgZn/g can be loaded with CIP amounts sufficient to completely suppress the growth of hospital strain Klebsiella oxytoca with MIC of 0.125 µg/mL, while maintaining a fibroblast viability at the level of 85-90%.

Biofunctionalization of dental abutments by a zinc/chitosan/gelatin coating to optimize fibroblast behavior and antibacterial properties

Tightly sealed peri-implant gingival tissue provides a barrier against oral bacterial invasion, protecting the alveolar bone and maintaining long-term implant survival. To investigate if zinc can enhance the integration between peri-implant gingival tissue and abutment surface, we herein present novel zinc/chitosan/gelatin (Zn/CS/Gel) coatings prepared using the electrophoretic deposition (EPD) technique. The effect of these coatings on human gingival fibroblasts (hGFs) was investigated by culturing these cells on top of the EPD coatings. Surface characterization demonstrated that Zn2+ were released in a sustained and pH-responsive manner. The preclinical cell culture evaluation of these coatings indicated that the zinc-containing coatings enhanced cell migration, adhesion and collagen secretion of hGFs. Moreover, the zinc-containing coatings exhibited antibacterial efficacy by inhibiting the growth of Porphyromonas gingivalis and reducing attachment of Staphylococcus aureus. Notably, zinc-free CS/Gel coatings prevented attachment of P. gingivalis as well. The coatings were also shown to be cytocompatible with epithelial cells and osteoblasts, which are other relevant cell types which surround dental implants after clinical placement. Based on our findings, it can be concluded that Zn-containing coatings hold promise to enhance the adhesion of gingival tissue to the implant surface, which may potentially contribute to the formation of a robust peri-implant soft sealing counteracting bacterial invasion.

Mussel-inspired sulfated hyaluronan cryogel patch with antioxidant, anti-inflammatory, and drug-loading properties for multifunctional wound adhesives

Wounds, characterized by the disruption of the continuity of body tissues resulting from external trauma, manifest in diverse types and locations. Although numerous wound dressings are available for various wound scenarios, it remains challenging to find an integrative wound dressing capable of addressing diverse wound situations. We focused on utilizing sulfated hyaluronan (sHA), known for its anti-inflammatory properties and capacity to load cationic drugs. By conjugating catechol groups to sHA (sHA-CA), we achieved several advantages in wound healing: 1) Fabrication of patches through crosslinking with catechol-modified high-molecular-weight hyaluronan (HA(HMW)-CA), 2) Adhesiveness that enabled stable localization, 3) Radical scavenging that could synergize with the immunomodulation of sHA. The sHA-CA patches demonstrated therapeutic efficacy in three distinct murine wound models: diabetic wound, hepatic hemorrhage, and post-surgical adhesion. Collectively, these findings underscore the potential of the sHA-CA patch as a promising candidate for the next-generation wound dressing.

Multifunctional Janus Membrane for Diabetic Wound Healing and Intelligent Monitoring

The complex microenvironment of diabetic wounds often hinders the healing process, ultimately leading to the formation of diabetic foot ulcers and even death. Dual monitoring and treatment of wounds can significantly reduce the incidence of such cases. Herein, a multifunctional Janus membrane (3D chitosan sponge-ZE/polycaprolactone nanofibers-ZP) was developed by incorporating the zinc metal-organic framework, europium metal-organic framework, and phenol red into nanofibers for diabetic wound monitoring and treatment. The directional water transport capacity of the resulting Janus membrane allows for unidirectional and irreversible drainage of wound exudate, and the multifunctional Janus membrane creates up to a 99% antibacterial environment, both of which can treat wounds. Moreover, the pH (5-8) and H2O2 (0.00-0.80 μM) levels of the wound can be monitored using the color-changing property of phenol red and the fluorescence characteristic of Eu-MOF on the obtained membrane, respectively. The healing stages of the wound can also be monitored by analyzing the RGB values of the targeted membrane images. This design can more accurately reflect the wound state and treat the wound to reduce bacterial infection and accelerate wound healing, which has been demonstrated in in vivo experiments. The results provide an important basis for early intervention in diabetic patients.

Cu-MOF loaded chitosan based freeze-dried highly porous dressings with anti-biofilm and pro-angiogenic activities accelerated Pseudomonas aeruginosa infected wounds healing in rats

Metal-organic frameworks (MOFs)-based therapy opens a new area for antibiotic-drug free infections treatment. In the present study, chitosan membranes (CS) loaded with two concentrations of copper-MOF 10 mg/20 ml (Cu-MOF10/CS) & 20 mg/20 ml (Cu-MOF20/CS) were prepared by a simple lyophilization procedure. FTIR spectra of Cu-MOF10/CS and Cu-MOF20/CS dressings confirmed absence of any undesirable chemical changes after loading Cu-MOF. The SEM images of the synthesized materials (CS, Cu-MOF10/CS & Cu-MOF20/CS) showed interconnected porous structures. Cytocompatibility of the materials was confirmed by fibroblasts cells culturing and the materials were hemocompatible, with blood clotting index <5 %. Cu-MOF20/CS showed comparatively higher effective antibacterial activity against the tested strains; E. coli (149.2 %), P. aeruginosa (165 %) S. aureus (117.8 %) and MRSA (142 %) as compared to Amikacin, CS and Cu-MOF10/CS membranes. Similarly, Cu-MOF20/CS dressing significantly eradicated the biofilms; P. aeruginosa (37 %) and MRSA (52 %) respectively. In full thickness infected wound rat model, on day 23, Cu-MOF10/CS and Cu-MOF20/CS promoted wound healing up to 87.7 % and 82 % respectively. H&E staining of wounded tissues treated with Cu-MOF10/CS & Cu-MOF20/CS demonstrated enhanced neovascularization and re-epithelization along-with reduced inflammation, while trichrome staining exhibited increased collagen deposition. Overall, this study declares Cu-MOFs loaded chitosan dressings a multifunctional platform for the healing of infected wounds.

3D Printing of Polysaccharide-Based Hydrogel Scaffolds for Tissue Engineering Applications: A Review

In tissue engineering, 3D printing represents a versatile technology employing inks to construct three-dimensional living structures, mimicking natural biological systems. This technology efficiently translates digital blueprints into highly reproducible 3D objects. Recent advances have expanded 3D printing applications, allowing for the fabrication of diverse anatomical components, including engineered functional tissues and organs. The development of printable inks, which incorporate macromolecules, enzymes, cells, and growth factors, is advancing with the aim of restoring damaged tissues and organs. Polysaccharides, recognized for their intrinsic resemblance to components of the extracellular matrix have garnered significant attention in the field of tissue engineering. This review explores diverse 3D printing techniques, outlining distinctive features that should characterize scaffolds used as ideal matrices in tissue engineering. A detailed investigation into the properties and roles of polysaccharides in tissue engineering is highlighted. The review also culminates in a profound exploration of 3D polysaccharide-based hydrogel applications, focusing on recent breakthroughs in regenerating different tissues such as skin, bone, cartilage, heart, nerve, vasculature, and skeletal muscle. It further addresses challenges and prospective directions in 3D printing hydrogels based on polysaccharides, paving the way for innovative research to fabricate functional tissues, enhancing patient care, and improving quality of life.

Facile synthesis of 2-hydroxy-β-cyclodextrin/polyacrylamide/carbazole hydrogel and its application for the treatment of infected wounds in a murine model

This work aimed to synthesize hydrogels by combining carbazole (Carb) with 2-hydroxy, β-cyclodextrin (HPβCD)/polyacrylamide (PAA) hybrid complexes. The hydrogels were then evaluated for their potential use in treating infected wounds. The physicochemical structures of the preparations were evaluated using several characterization methods including FTIR, FESEM, EDX, XRD, pH sensitivity, and TGA. Moreover, In vitro release, toxicity, antibacterial activity and in vivo infected wound healing activity were evaluated. Physicochemical testing verified the effective synthesis of the preparations and the timely release of Carb. The P(AA-co-AM)/HPβCD material exhibited an open structure characterized by macroscopic voids, whereas the hydrogels displayed surfaces that were not uniform. The FTIR analysis revealed the creation of a novel polymeric hydrogel composed of HPβCD as the main polymer structure. The hydrogels exhibited good reversible swelling and recoverable deformation, with an optimal swelling ratio of 30.12 achieved at pH 7.4. The antibacterial and safety of the formulations were validated by in vitro studies. β.Dex/PAA/Carb hydrogels have been shown to effectively expedite the healing of infected wounds by promoting the production of CD31, FGF-2, and COL1A, while reducing the levels of ROS, CD68, COX-2, and NF-κB. Overall, the combination of Carb, β.Dex, and PAA molecules had a synergistic impact on the healing process of infected wounds.

Extracellular Matrix-Bioinspired Anisotropic Topographical Cues of Electrospun Nanofibers: A Strategy of Wound Healing through Macrophage Polarization

The skin serves as the body's outermost barrier and is the largest organ, providing protection not only to the body but also to various internal organs. Owing to continuous exposure to various external factors, it is susceptible to damage that can range from simple to severe, including serious types of wounds such as burns or chronic wounds. Macrophages play a crucial role in the entire wound-healing process and contribute significantly to skin regeneration. Initially, M1 macrophages infiltrate to phagocytose bacteria, debris, and dead cells in fresh wounds. As tissue repair is activated, M2 macrophages are promoted, reducing inflammation and facilitating restoration of the dermis and epidermis to regenerate the tissue. This suggests that extracellular matrix (ECM) promotes cell adhesion, proliferation, migrationand macrophage polarization. Among the numerous strategies, electrospinning is a versatile technique for obtaining ECM-mimicking structures with anisotropic and isotropic topologies of micro/nanofibers. Various electrospun biomaterials influence macrophage polarization based on their isotropic or anisotropic topologies. Moreover, these fibers possess a high surface-area-to-volume ratio, promoting the effective exchange of vital nutrients and oxygen, which are crucial for cell viability and tissue regeneration. Micro/nanofibers with diverse physical and chemical properties can be tailored to polarize macrophages toward skin regeneration and wound healing, depending on specific requirements. This review describes the significance of micro/nanostructures for activating macrophages and promoting wound healing.

Chrysin loaded polycaprolactone-chitosan electrospun nanofibers as potential antimicrobial wound dressing

In this study, various concentrations of chrysin (chry) were loaded into polycaprolactone-chitosan (PCL-CTS) nanofibers to develop a potential wound dressing materials using electrospinning method. The structural composition and the morphology of the produced PCL-CTS5, PCL-CTS10 and PCL-CTS15 were analyzed by FE-SEM and FTIR, respectively. By increasing the amount of chry, the average diameter of the nanofibres was also increased to 191 ± 65 nm, 203 ± 72 nm, and 313 ± 69 nm for PCL-CTS5, PCL-CTS10, and PCL-CTS15, respectively. Moreover, the physicochemical characteristics and biological properties of synthesized nanofibers such as tensile testing, in-vitro drug release, porosity, decomposition rate, water absorption rate, water vapor permeability rate, cell viability, antioxidant and antibacterial activity were evaluated. By using Korsmeyer-Peppas and Higuchi kinetic models, the chry release mechanism in all nanofibers was studied in PBS solution, which suggested a Fick's diffusion. In-vitro antioxidant experiments by DPPH assay indicated 24, 43, 61 and 78 % free radical scavenging activity for PCL-CTS, PCL-CTS5, PCL-CTS10 and PCL-CTS15. In-vitro antibacterial examination showed that chry-loaded nanofibers had high antibacterial activity in which were comparable with the standard reagents. In-vitro cytotoxicity results obtained by MTT assay indicated a desired cytocompatibility towards fibroblast cells.

Polysaccharide hydrogel containing silver nanoparticle@catechol microspheres with photothermal, antibacterial and anti-inflammatory activities for infected-wounds repair

Anti-infection hydrogels have recently aroused enormous attraction, particularly in the treatment of chronic wounds. Herein, silver nanoparticle@catechol formaldehyde resin microspheres (Ag@CFRs) were fabricated by one-step hydrothermal method and subsequently encapsulated in hydrogels which were developed by Schiff base reaction between aldehyde groups in oxidized hyaluronic acid and amino groups in carboxymethyl chitosan. The developed polysaccharide hydrogel exhibited microporous structure, high swelling capacity, favorable mechanical strength, enhanced tissue adhesion and photothermal activities. Additionally, the hydrogel not only ensured long-term and high-efficiency antibacterial performance (99.9 %) toward E. coli and S. aureus, but also realized superior cytocompatibility in vitro. Moreover, based on the triple antibacterial strategies endowed by chitosan, silver nanoparticles and the photothermal properties of catechol microspheres, the composite hydrogel exhibited excellent anti-infection function, significantly downregulated inflammatory factors (TNF-α and IL-1β) and promoted in vivo infected-wound healing. These results demonstrated that the polysaccharide hydrogel containing Ag@CFRs has great potential for infected-wounds repair.

Dual-crosslinked methacrylamide chitosan/poly(ε-caprolactone) nanofibers sequential releasing of tannic acid and curcumin drugs for accelerating wound healing

The objective of this research study is to develop novel composite nanofibers based on methacrylamide chitosan (ChMA)/poly(ε-caprolactone) (PCL) materials by the dual crosslinking and coaxial-electrospinning strategies. The prepared ChMA/PCL composite nanofibers can sequentially deliver tannic acid and curcumin drugs to synergistically inhibit bacterial reproduction and accelerate wound healing. The rapid delivery of tannic acid is expected to inhibit pathogenic microorganisms and accelerate epithelialization in the early stage, while the slow and sustained release of curcumin is with the aim of relieving chronic inflammatory response and inducing dermal tissue maturation in the late stage. Meanwhile, dual-drugs sequentially released from the membrane exhibited a DPPH free radical scavenging rate of ca. 95 % and an antibacterial rate of above 85 %. Moreover, the membrane possessed great biocompatibility in vitro and significantly inhibited the release of pro-inflammatory factors (IL-1β and TNF-α) in vivo. Animal experiments showed that the composite membrane by means of the synergistic effect of polyphenol drugs and ChMA nanofibers, could significantly alleviate macrophage infiltration and accelerate the healing process of wounds. From the above, the as-prepared ChMA-based membrane with a stage-wise release pattern of drugs could be a promising bioengineered construct for wound healing application.