Novel fabrication of antibiotic containing multifunctional silk fibroin injectable hydrogel dressing to enhance bactericidal action and wound healing efficiency on burn wound: In vitro and in vivo evaluations

Advancing burn wound treatment: exploring hydrogel as a transdermal drug delivery system

Burn injuries are prevalent and life-threatening forms that contribute significantly to mortality rates due to associated wound infections. The management of burn wounds presents substantial challenges. Hydrogel exhibits tremendous potential as an ideal alternative to traditional wound dressings such as gauze. This is primarily attributed to its three-dimensional (3D) crosslinked polymer network, which possesses a high water content, fostering a moist environment that supports effective burn wound healing. Additionally, hydrogel facilitates the penetration of loaded therapeutic agents throughout the wound surface, combating burn wound pathogens through the hydration effect and thereby enhancing the healing process. However, the presence of eschar formation on burn wounds obstructs the passive diffusion of therapeutics, impairing the efficacy of hydrogel as a wound dressing, particularly in cases of severe burns involving deeper tissue damage. This review focuses on exploring the potential of hydrogel as a carrier for transdermal drug delivery in burn wound treatment. Furthermore, strategies aimed at enhancing the transdermal delivery of therapeutic agents from hydrogel to optimize burn wound healing are also discussed.

Hyaluronic Acid/Gelatin-Based Multifunctional Bioadhesive Hydrogel Loaded with a Broad-Spectrum Bacteriocin for Enhancing Diabetic Wound Healing

The development of multifunctional wound adhesives is critical in clinical settings due to the scarcity of dressings with effective adhesive properties while protecting against infection by drug-resistant bacteria. Polysaccharide and gelatin-based hydrogels, known for their biocompatibility and bioactivity, assist in wound healing. This study introduces a multifunctional bioadhesive hydrogel developed through dynamic covalent bonding and light-triggered covalent bonding, comprising oxidized hyaluronic acid, methacrylated gelatin, and the bacteriocin recently discovered by our lab, named jileicin (JC). The adhesion strength of the hydrogel, measured at 180 kPa, was 4.35 times higher than that of the fibrin glue. Furthermore, the hydrogel demonstrated robust platelet adhesion, procoagulant activity, and outstanding hemostatic properties in a mouse liver injury model. Incorporating JC significantly enhanced the phagocytosis and bactericidal capabilities of the macrophages. This immunomodulatory function on host cells, coupled with its potent bacterial membrane-disrupting ability, makes JC an effective killer against methicillin-resistant Staphylococcus aureus. In wound repair experiments on diabetic mice with infected full-thickness skin defects, the hydrogel treatment group showed a notable reduction in bacterial load, accelerated M2-type macrophage polarization, diminished inflammation, and hastened wound healing. Owing to its outstanding biocompatibility, antibacterial activity, and controlled adhesion, this hydrogel presents a promising therapeutic option for treating infected skin wounds.

Novel theranostic wounds dressing based on pH responsive alginate hydrogel/graphene oxide/levofloxacin modified silk

Integrating pH sensor with controlled antibiotic release is fabricated on silk to create a theranostic wound dressing. Alginate (ALG) hydrogel and graphene oxide (GO) loaded with levofloxacin (LVX) and a pH indicator are applied to fabricate a pH-responsive theranostic wound dressing. The modified silk color changes from yellow to green in response to elevated skin pH, indicating the skin infection. The semi-quantitative analysis was conducted using ImageJ, revealing significant color changes across the wide range. At elevated pH levels, the ionization of the COOH bonds within ALG induces repulsion among the COO- groups, thereby accelerating the release of the incorporated drug compared to release under lower pH. At an infected pH of 8, ALG hydrogel triggers LVX releasing up to 135.86 ± 0.3 µg, while at a normal pH of 7, theranostic silk releases 123.13 ± 0.26 µg. Incorporating GO onto silk fibers enhances LVX loading and sustains LVX release. Furthermore, these modified silks possess antimicrobial abilities without causing irritation or allergies on the human skin. This theranostic silks represents a major step forward in smart wound care, introducing a versatile platform of smart wound care.

A 3D bioprinted antibacterial hydrogel dressing of gelatin/sodium alginate loaded with ciprofloxacin hydrochloride

Skin plays a crucial role in human physiological functions, however, it was vulnerable to bacterial infection which delayed wound healing. Nowadays, designing an individual wound dressing with good biocompatibility and sustaining anti-infection capability for healing of chronic wounds are still challenging. In this study, various concentrations of the ciprofloxacin (CIP) were mixed with gelatine (Gel)/sodium alginate (SA) solution to prepare Gel/SA/CIP (GAC) bioinks, following the fabrication of GAC scaffold by an extrusion 3D bioprinting technology. The results showed that the GAC bioinks had good printability and the printed GAC scaffolds double-crosslinked by EDC/NHS and CaCl2 had rich porous structure with appropriate pore size, which were conducive to drug release and cell growth. It demonstrated that the CIP could be rapidly released by 70% in 5 min, which endowed the GAC composite scaffolds with an excellent antibacterial ability. Especially, the antibacterial activities of GAC7.5 against Escherichia coli and Staphylococcus aureus within 24 h were even close to 100%, and the inhibition zones were still maintained 14.78 ± 0.40 mm and 14.78 ± 0.40 mm, respectively, after 24 h. Meanwhile, GAC7.5 also demonstrated impressive biocompatibility which can promote the growth and migration of L929 and accelerate wound healing. Overall, the GAC7.5 3D bioprinting scaffold could be used as a potential skin dressing for susceptible wounds with excellent antibacterial activity and good biocompatibility to meet urgent clinical needs.

Exploring the mechanistic role of silk sericin biological and chemical conjugates for effective acute and chronic wound repair and related complications

OBJECTIVE

The current review is designed to elaborate and reveal the underlying mechanism of sericin and its conjugates of drug delivery during wounds and wound-related issues.

SIGNIFICANCE

Wound healing is a combination of different humoral, molecular, and cellular mechanisms. Various natural products exhibit potential in wound healing but among them, sericin, catches much attention of researchers due to its bio-functional properties such as being biodegradable, biocompatible, anti-oxidant, anti-bacterial, photo-protector, anti-inflammatory and moisturizing agent.

METHODS AND RESULTS

Sericin triggers the activity of anti-inflammatory cytokines which decrease cell adhesion and promote epithelial cell formation. Moreover, sericin enhances the anti-oxidant enzymes in the wounded area which scavenge the toxic consequences of reactive species (ROS).

CONCLUSIONS

This article highlights the mechanisms of how topical administration of sericin formulations along with 4-hexylresorcinol,\Chitosan\Ag@MOF-GO, polyvinyl alcohol (PVA), platelet lysate and UV photo cross-linked hydrogel sericin methacrylate which recruits a large number of cytokines on wounded area that stimulate fibroblasts and keratinocyte production as well as collagen deposition that led to early wound contraction. It also reviews the different sericin-based nanoparticles that play a significant role in rapid wound healing.

Progress in Wound-Healing Products Based on Natural Compounds, Stem Cells, and MicroRNA-Based Biopolymers in the European, USA, and Asian Markets: Opportunities, Barriers, and Regulatory Issues

Wounds are breaks in the continuity of the skin and underlying tissues, resulting from external causes such as cuts, blows, impacts, or surgical interventions. Countless individuals suffer minor to severe injuries, with unfortunate cases even leading to death. In today's scenario, several commercial products are available to facilitate the healing process of wounds, although chronic wounds still present more challenges than acute wounds. Nevertheless, the huge demand for wound-care products within the healthcare sector has given rise to a rapidly growing market, fostering continuous research and development endeavors for innovative wound-healing solutions. Today, there are many commercially available products including those based on natural biopolymers, stem cells, and microRNAs that promote healing from wounds. This article explores the recent breakthroughs in wound-healing products that harness the potential of natural biopolymers, stem cells, and microRNAs. A comprehensive exploration is undertaken, covering not only commercially available products but also those still in the research phase. Additionally, we provide a thorough examination of the opportunities, obstacles, and regulatory considerations influencing the potential commercialization of wound-healing products across the diverse markets of Europe, America, and Asia.

Injectable and Thermosensitive Hydrogel with Platelet-Rich Plasma for Enhanced Biotherapy of Skin Wound Healing

The rapid and effective healing of skin wounds resulted from severe injuries and full-layer skin defects remains a pressing clinical challenge in contemporary medical practice. The reduction of wound infection and rapid healing is helpful to rebuild and repair skin tissue. Here, a thermosensitive chitosan-based wound dressing hydrogel incorporating β-glycerophosphate (GP), hydroxy propyl cellulose (HPC), graphene oxide (GO), and platelet-rich plasma (PRP) is developed, which exhibits the dual functions of antibacterial properties and repair promotion. GP and HPC enhance the mechanical properties through forming hydrogen bonding connection, while GO produces local heat under near-infrared light, leading to improved blood circulation and skin recovery. Notably, antibacterial properties against Pseudomonas aeruginosa, and control-release of growth factors from PRP are also achieved based on the system. In vitro experiments reveal its biocompatibility, and ability to promote cell proliferation and migration. Animal experiments demonstrate that the epithelial repair and collagen deposition can be promoted during skin wound healing in Sprague Dawley rats. Moreover, a reduction in wound inflammation levels and the improvement of wound microenvironment are observed, collectively fostering effective wound healing. Therefore, the composite hydrogel system incorporated with GO and PRP can be a promising dressing for the treatment of skin wounds.

Bacterial cellulose as an ideal potential treatment for burn wounds: A comprehensive review

Burn wound regeneration is a complex process, which has many serious challenges such as slow wound healing, secondary infection, and inflammation. Therefore, it is essential to utilise appropriate biomaterials to accelerate and guide the wound healing process. Bacterial cellulose (BC), a natural polymer synthesised by some bacteria, has attracted much attention for wound healing applications due to its unique properties including excellent physicochemical and mechanical properties, simple purification process, three-dimensional (3D) network structure similar to extracellular matrix, high purity, high water holding capacity and significant permeability to gas and liquid. BC's lack of antibacterial activity significantly limits its biomedical and tissue engineering application, but adding antimicrobial agents to it remarkably improves its performance in tissue regeneration applications. Burn wound healing is a complex long-lasting process. Using biomaterials in wound treatment has shown that they can satisfactorily accelerate wound healing. The purpose of this review is to elaborate on the importance of BC-based structures as one of the most widely used modern wound dressings in the treatment of burn wounds. In addition, the combination of various drugs, agents, cells and biomolecules with BC to expand its application in burn injury regeneration is discussed. Finally, the main challenges and future development direction of BC-based structures for burn wound repair are considered. The four most popular search engines PubMed/MEDLINE, Science Direct, Scopus and Google Scholar were used to help us find relevant papers. The most frequently used keywords were bacterial cellulose, BC-based biocomposite, wound healing, burn wound and vascular graft.

Local application of gingiva-derived mesenchymal stem cells on experimental periodontitis in rats

BACKGROUND

Stem cell-based approaches in regenerative periodontal therapy have been used in different experimental models. In this study, the effect of local application of gingival mesenchymal stem cells (GMSC) in fibroin/chitosan oligosaccharide lactate hydrogel (F/COS) on periodontal regeneration was evaluated using experimental periodontitis model in rats.

METHODS

Mesenchymal stem cells were isolated from the gingiva of rats and characterized. Viability tests and confocal imaging of GMSC in hydrogels were performed. Healthy control without periodontitis (Health; H; n=10), control with periodontitis but no application (Periodontitis; P; n=10), only hydrogel application (F/COS; n=10), and GMSC+F/COS (n=10) four groups were formed for in vivo studies. Experimental periodontitis was created with silk sutures around the maxillary second molars. GMSC labeled with green fluorescent protein (GFP) (250,000 cells/50 μL) in F/COS were applied to the defect. Animals were sacrificed at 2nd and 8th weeks and maxillae of the animals were evaluated by micro-computed tomography (micro-CT) and histologically. The presence of GFP-labeled GMSC was confirmed at the end of 8 weeks.

RESULTS

Micro-CT analysis showed statistically significant new bone formation in the F/COS+GMSC treated group compared with the P group at the end of 8 weeks (p < 0.05). New bone formation was also observed in the F/COS group, but the statistical analysis revealed that this difference was not significant when compared with the P group (p > 0.05). Long junctional epithelium formation was less in the F/COS+GMSC group compared with the P group. Periodontal ligament and connective tissue were well-organized in F/COS+GMSC group.

CONCLUSION

The results showed that local GMSC application in hydrogel contributed to the formation of new periodontal ligament and alveolar bone in rats with experimental periodontitis. Since gingiva is easly accessible tissue, it is promising for autologous cell-based treatments in clinical applications.

Silk fibroin-based scaffolds for tissue engineering

Silk fibroin is an important natural fibrous protein with excellent prospects for tissue engineering applications. With profound studies in recent years, its potential in tissue repair has been developed. A growing body of literature has investigated various fabricating methods of silk fibroin and their application in tissue repair. The purpose of this paper is to trace the latest developments of SF-based scaffolds for tissue engineering. In this review, we first presented the primary and secondary structures of silk fibroin. The processing methods of SF scaffolds were then summarized. Lastly, we examined the contribution of new studies applying SF as scaffolds in tissue regeneration applications. Overall, this review showed the latest progress in the fabrication and utilization of silk fibroin-based scaffolds.

Hydrogels in Cutaneous Wound Healing: Insights into Characterization, Properties, Formulation and Therapeutic Potential

Hydrogels are polymeric materials that possess a set of characteristics meeting various requirements of an ideal wound dressing, making them promising for wound care. These features include, among others, the ability to absorb and retain large amounts of water and the capacity to closely mimic native structures, such as the extracellular matrix, facilitating various cellular processes like proliferation and differentiation. The polymers used in hydrogel formulations exhibit a broad spectrum of properties, allowing them to be classified into two main categories: natural polymers like collagen and chitosan, and synthetic polymers such as polyurethane and polyethylene glycol. This review offers a comprehensive overview and critical analysis of the key polymers that can constitute hydrogels, beginning with a brief contextualization of the polymers. It delves into their function, origin, and chemical structure, highlighting key sources of extraction and obtaining. Additionally, this review encompasses the main intrinsic properties of these polymers and their roles in the wound healing process, accompanied, whenever available, by explanations of the underlying mechanisms of action. It also addresses limitations and describes some studies on the effectiveness of isolated polymers in promoting skin regeneration and wound healing. Subsequently, we briefly discuss some application strategies of hydrogels derived from their intrinsic potential to promote the wound healing process. This can be achieved due to their role in the stimulation of angiogenesis, for example, or through the incorporation of substances like growth factors or drugs, such as antimicrobials, imparting new properties to the hydrogels. In addition to substance incorporation, the potential of hydrogels is also related to their ability to serve as a three-dimensional matrix for cell culture, whether it involves loading cells into the hydrogel or recruiting cells to the wound site, where they proliferate on the scaffold to form new tissue. The latter strategy presupposes the incorporation of biosensors into the hydrogel for real-time monitoring of wound conditions, such as temperature and pH. Future prospects are then ultimately addressed. As far as we are aware, this manuscript represents the first comprehensive approach that brings together and critically analyzes fundamental aspects of both natural and synthetic polymers constituting hydrogels in the context of cutaneous wound healing. It will serve as a foundational point for future studies, aiming to contribute to the development of an effective and environmentally friendly dressing for wounds.

Formulation and Comprehensive Evaluation of Biohybrid Hydrogel Membranes Containing Doxycycline or Silver Nanoparticles

Complicated wounds often require specialized medical treatments, and hydrogels have emerged as a popular choice for wound dressings in such cases due to their unique properties and the ability to incorporate and release therapeutic agents. Our focus was to develop and characterize a new optimized formula for biohybrid hydrogel membranes, which combine natural and synthetic polymers, bioactive natural compounds, like collagen and hyaluronic acid, and pharmacologically active substances (doxycycline or npAg). Dynamic (oscillatory) rheometry confirmed the strong gel-like properties of the obtained hydrogel membranes. Samples containing low-dose DOXY showed a swelling index of 285.68 ± 6.99%, a degradation rate of 71.6 ± 0.91% at 20 h, and achieved a cumulative drug release of approximately 90% at pH 7.4 and 80% at pH 8.3 within 12 h. The addition of npAg influenced the physical properties of the hydrogel membranes. Furthermore, the samples containing DOXY demonstrated exceptional antimicrobial efficacy against seven selected bacterial strains commonly associated with wound infections and complications. Biocompatibility assessments revealed that the samples exhibited over 80% cell viability. However, the addition of smaller-sized nanoparticles led to decreased cellular viability. The obtained biohybrid hydrogel membranes show favorable properties that render them suitable for application as wound dressings.

Fabrication andin vitroevaluation of photo cross-linkable silk fibroin-epsilon-poly-L-lysine hydrogel for wound repair

An optimal wound-healing hydrogel requires effective antibacterial properties and a favorable cell adhesion and proliferation environment. AlthoughBombyx morisilk fibroin (SF) possesses inherent wound-healing properties, it lacks these essential qualities. This study aimed to fabricate a novel photo-polymerizable hydrogel by utilizing SF's wound-healing efficiency and the epsilon-poly-L-lysine (EPL) antimicrobial activity. The SF was modified with three different concentrations of glycidyl methacrylate (GMA) to obtain SF-GMA(L), SF-GMA(M), and SF-GMA(H). A methacrylated EPL (EPL-GMA) was also produced. Then, SF-GMA was mixed with EPL-GMA to produce photo-crosslinkable SF-GMA-EPL hydrogels. The SF-GMA(L)-EPL, SF-GMA(M)-EPL, and SF-GMA(H)-EPL hydrogels, fabricated with 20% EPL-GMA, demonstrated maximum antimicrobial activity and mammalian cell adhesion ability. The hydroxyl radical (•OH) scavenging efficiency of the hydrogels was tested and shown to be between 69% and 74%. These hydrogels also exhibited 60% efficiency in removing bacterial lipopolysaccharides. The water absorption ability of the hydrogels was consistent with the size of their internal pores. The hydrogels exhibited a slow degradation fashion, and their degradation products appeared cytocompatible. Finally, the elastomeric properties of the hydrogels were determined, and a storage modulus (G') of 300-600 Pa was demonstrated. In conclusion, the hydrogels created in this study possess excellent biological and physical properties to support wound healing.

Cellulose based self-healing hydrogel through Boronic Ester connections for wound healing and antitumor applications

The application of biodegradable hydrogels in medical field has drawn great attention because their networked structure provided ideal spaces for drug loading and cell growth. In this research, the boronic acid was coupled onto carboxyethyl cellulose (CMC) to synthesize boronic acid grafted CMC (CMC-BA) conveniently and self-healing hydrogel was fabricated with polyvinyl alcohol (PVA) crosslinking through dynamic boronic ester bond. The CMC-BA/PVA hydrogel showed good biocompatibility and could be degraded by cellulase and in vivo. The hydrogel formed fast fit for localized injection to cover the irregular wounds and localize the antitumor drugs to the tumor site. The in vivo wound repairing experiment revealed the hydrogel could form airtight adhesion to the wound site to reduce blood loss and accelerate the wound repairing rate. The hydrogel as a drug release carrier also reduced the acute in vivo toxicity of DOX with antitumor performance well preserved through a controlled release profile. Based on the above advantages, the CMC-based hydrogel with boronic ester connection should have great potential in biomedical areas with profitable future.

Synthesis and characterization of a novel, pH-responsive sustained release nanocarrier using polyethylene glycol, graphene oxide, and natural silk fibroin protein by a green nano emulsification method to enhance cancer treatment

In this study, for the first time, by employing a simple and efficient double nano-emulsification method and using sweet almond oil as the organic phase, polyethylene glycol (PEG)/graphene oxide (GO)/silk fibroin (SF) hydrogel-nanocomposite was synthesized. The aim of the research was to fabricate a biocompatible targeted pH-sensitive sustained release carrier, improve the drug loading capacity and enhance the anticancer effect of doxorubicin (DOX) drug. The obtained values for the entrapment (%EE) and loading efficacy (%LE) were 87.75 ± 0.7 % and 46 ± 1 %, respectively, and these high values were due to the use of GO with a large specific surface area and the electrostatic interaction between the drug and SF. The Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses confirmed the presence of all the components in the nanocomposite and the suitable interaction between them. Based on the results of dynamic light scattering analysis (DLS) and zeta potential analysis, the mean size of the carrier particles and its surface charge were 293.7 nm and -102.9 mV, respectively. The high negative charge was caused by the presence of hydroxyl groups in GO and SF and it caused proper stability of the nanocomposite. The spherical core-shell structure with its homogeneous surface was also observed in the field emission scanning electron microscopy (FE-SEM) image. The cumulative release percentage of the nanocarrier reached 95.75 after 96 h and it is higher in the acidic environment at all times. The results of fitting the release data to the kinetic models suggested that the mechanism of release was dissolution-controlled anomalous at pH 7.4 and diffusion-controlled anomalous at pH 5.4. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry showed an increase in toxicity on MCF-7 cells and improved apoptotic cell death compared to the free drug. Consequently, the findings of this research introduced and confirmed PEG/GO/SF nanocomposite as an attractive novel drug delivery system for pH-sensitive and sustained delivery of chemotherapeutic agents in biomedicine.

Silk Fibroin Hydrogels Could Be Therapeutic Biomaterials for Neurological Diseases

Silk fibroin, a natural macromolecular protein without physiological activity, has been widely used in different fields, such as the regeneration of bones, cartilage, nerves, and other tissues. Due to irrevocable neuronal injury, the treatment and prognosis of neurological diseases need to be investigated. Despite attempts to propel neuroprotective therapeutic approaches, numerous attempts to translate effective therapies for brain disease have been largely unsuccessful. As a good candidate for biomedical applications, hydrogels based on silk fibroin effectively amplify their advantages. The ability of nerve tissue regeneration, inflammation regulation, the slow release of drugs, antioxidative stress, regulation of cell death, and hemostasis could lead to a new approach to treating neurological disorders. In this review, we introduced the preparation of SF hydrogels and then delineated the probable mechanism of silk fibroin in the treatment of neurological diseases. Finally, we showed the application of silk fibroin in neurological diseases.

A proof-of-concept study of the removal of early and late phase biofilm from skin wound models using a liquid acoustic stream

Chronic wounds fail to progress through the normal stages of healing, with the largest remediable cause of chronicity being presence of a multi-species biofilm. Removal of biofilm from the wound environment is central to wound care. A device for mechanically removing biofilms from wounds has been devised. The removal is caused by small-scale liquid currents and shear, generated by acoustically activated microscopic air bubbles. These bubbles and acoustic waves are delivered onto the wound by a gentle liquid stream, allowing cleaning in situ and removal of debris in the run-off liquid. We have investigated if this liquid acoustic wound stream (LAWS) can remove bacterial biofilm from soft biological wound models and studied the effect of LAWS on the cellular tissues of the substrate. LAWS will efficiently remove early Pseudomonas aeruginosa biofilm from an artificial wound in a pig's trotter, 24 hours-mature biofilm of P. aeruginosa from a pre-wounded human full thickness skin model (EpiDerm FT), and 3-day mature biofilm of P. aeruginosa or Staphylococcus aureus from a porcine skin explant. Histological examinations of uninfected EpiDerm models that had been treated by LAWS and then stained with Haematoxylin and Eosin, demonstrated no damage to the human tissue, and wound diameter was smaller in the treated skin models compared with untreated samples. Immunofluorescence staining for cytokeratin 14 showed that keratinocytes had migrated further across the wound in the uninfected samples treated by LAWS. We discuss the implications for wound healing and propose further laboratory and clinical studies to demonstrate the removal of biofilm from patients with chronic leg ulcers and the impact on healing.