Wound-dressing materials with antibacterial activity from electrospun polyurethane-dextran nanofiber mats containing ciprofloxacin HCl

Two-dimensional nanomaterials: A multifunctional approach for robust for diabetic wound repair

Diabetic wounds pose a clinical challenge due to persistent inflammation, severe bacterial infections, inadequate vascularization, and pronounced oxidative stress. Current therapeutic modalities fail to provide satisfactory outcomes in managing these conditions, resulting in considerable patient distress. Two-dimensional nanomaterials (2DNMs), characterized by their unique nanosheet structures, expansive surface areas, and remarkable physicochemical properties, have garnered considerable attention for their potential in therapeutic applications. Emerging 2DNMs can be loaded with various pharmacological agents, including small molecules, metal ions, and liposomes. Moreover, they can be integrated with various biomaterials such as hydrogels, microneedles, and microspheres, thus demonstrating unprecedented advantages in expediting the healing process of diabetic wounds. Moreover, 2DNMs exhibit exceptional performance characteristics, including high biocompatibility, effective antimicrobial properties, optimal phototherapeutic effects, and enhanced electrostimulation capabilities. These properties enable them to modulate the wound microenvironment, leading to widespread application in tissue repair with remarkable outcomes. This review delineates several emerging 2DNMs, such as graphene and its derivatives, black phosphorus, MXenes, and transition metal dichalcogenides, in the context of diabetic wound repair. Furthermore, it elucidates the translational challenges and future perspectives of 2DNMs in wound healing treatments. Overall, 2DNMs present a highly promising strategy for ameliorating diabetic wounds, thus providing novel avenues for diagnostic and therapeutic strategies in diabetic wound management.

Enhancing cellular affinity for skin disorders: Electrospun polyurethane/collagen nanofiber mats coated with phytoceramides

Although the use of thermoplastic polyurethane (Tpu) nanofiber mats as wound dressings is of great interest due to their mechanical properties, they are hindered by their poor wettability and bioavailability. In this study, we aimed to improve the cellular affinity of Tpu nanofiber mats for skin disorders by incorporating extracted collagen (Col) from tendons and physically mixed with a layer of phytoceramides (Phyto) to produce TpuCol@X-Phyto mats in which the weight % of Phyto relatively to the weight of the solution was X = 0.5, 1.0, or 1.5 wt% via facile electrospinning approach. The collective observations strongly indicate the successful incorporation and retention of Phyto within the TpuCol architecture. An increase in the Phyto concentration decreased the water contact angle from 69.4° ± 3.47° to 57.9° ± 2.89°, demonstrating improvement in the hydrophilicity of Tpu and binary blend TpuCol nanofiber mats. The mechanical property of 1.0 wt% Phyto aligns with practical requirements owing to the presence of two hydroxyl groups and the amide linkage likely contributing to various hydrogen bonds, providing mechanical strength to the channel structure and a degree of rigidity essential for transmitting mechanical stress. The proliferation of human skin fibroblast (HSF) peaked significantly 100 % with TpuCol@X-Phyto mats coated for X =1.0 and 1.5 wt% of Phyto. Electrospun scaffolds with the highest Phyto content have shown the lowest degree of hemolysis, demonstrating the high level of compatibility between them and blood. The TpuCol@1.5Phyto mat also demonstrated higher efficacy in antibacterial and antioxidant activities, achieving a rate of DPPH radical scavenging of 83.3 % for this latter property. The most notable wound closure among all tested formulations was attributed to higher Phyto. Thus, the developed TpuCol@1.5Phyto nanofiber formula exhibited enhanced healing in an in vitro epidermal model.

Advances of antimicrobial dressings loaded with antimicrobial agents in infected wounds

Wound healing is a complex process that is critical for maintaining the barrier function of the skin. However, when a large quantity of microorganisms invade damaged skin for an extended period, they can cause local and systemic inflammatory responses. If left untreated, this condition may lead to chronic infected wounds. Infected wounds significantly escalate wound management costs worldwide and impose a substantial burden on patients and healthcare systems. Recent clinical trial results suggest that the utilization of effective antimicrobial wound dressing could represent the simplest and most cost-effective strategy for treating infected wounds, but there has hitherto been no comprehensive evaluation reported on the efficacy of antimicrobial wound dressings in promoting wound healing. Therefore, this review aims to systematically summarize the various types of antimicrobial wound dressings and the current research on antimicrobial agents, thereby providing new insights for the innovative treatment of infected wounds.

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.

Multifunctional double-network hydrogel with antibacterial and anti-inflammatory synergistic effects contributes to wound healing of bacterial infection

Wound infection not only hinders the time sequence of tissue repair, but also may lead to serious complications. Multifunctional wound dressings with biocompatibility, excellent mechanical properties and antibacterial properties can promote wound healing during skin infection and reduce the use of antibiotics. In this study, a multifunctional dual-network antibacterial hydrogel was constructed based on the electrostatic interaction of two polyelectrolytes, hydroxypropyl trimethyl ammonium chloride chitosan (HACC) and sodium alginate (SA). Attributing to the suitable physical crosslinking between HACC and SA, the hydrogel not only has good biocompatibility, mechanical property, but also has broad-spectrum antibacterial properties. In vivo results showed that the hydrogel could regulate M2 polarization, promote early vascular regeneration, and create a good microenvironment for wound healing. Therefore, this hydrogel is an effective multifunctional wound dressing. Consequently, we propose a novel hydrogel with combined elements to expedite the intricate repair of wound infection.

A review of the current state of natural biomaterials in wound healing applications

Skin, the largest biological organ, consists of three main parts: the epidermis, dermis, and subcutaneous tissue. Wounds are abnormal wounds in various forms, such as lacerations, burns, chronic wounds, diabetic wounds, acute wounds, and fractures. The wound healing process is dynamic, complex, and lengthy in four stages involving cells, macrophages, and growth factors. Wound dressing refers to a substance that covers the surface of a wound to prevent infection and secondary damage. Biomaterials applied in wound management have advanced significantly. Natural biomaterials are increasingly used due to their advantages including biomimicry of ECM, convenient accessibility, and involvement in native wound healing. However, there are still limitations such as low mechanical properties and expensive extraction methods. Therefore, their combination with synthetic biomaterials and/or adding bioactive agents has become an option for researchers in this field. In the present study, the stages of natural wound healing and the effect of biomaterials on its direction, type, and level will be investigated. Then, different types of polysaccharides and proteins were selected as desirable natural biomaterials, polymers as synthetic biomaterials with variable and suitable properties, and bioactive agents as effective additives. In the following, the structure of selected biomaterials, their extraction and production methods, their participation in wound healing, and quality control techniques of biomaterials-based wound dressings will be discussed.

Silver nanoparticle reinforced polylactic acid and gelatin composite films for advanced wound dressing

Multifunctional and biodegradable dressings with high mechanical strength and good antibacterial activity are crucial in fundamental health services. This study was initiated to prepare a novel curative wound dressing film consisting of natural biodegradable gelatin (G) and polylactic acid (PLA) with silver nanoparticles (AgNPs) where glutaraldehyde (GA) was used as compatibilizer. The prepared composite films addressed the poor thermal and biological stability of G and the limited fluid retention capacity of PLA. Silver nanoparticles were prepared by basic chemical reduction and reinforced on polymer films using simple solvent casting, which obviated common clinical infections and accelerated wound closure rate (p < .05). Fourier transform infrared (FTIR) studies confirmed composite formation through H-bonding and X-ray diffraction (XRD) revealed increased crystallinity due to incorporating AgNPs. Films with G, PLA & GA (50:50:5 by volume) introduced the best elasticity & strength with excellent fluid retention properties (p < .05). Scanning electron microscopy (SEM) images unfolded surface morphology and presence of agglomerated AgNPs on film surfaces. Prepared films exhibited significant antimicrobial efficacy against Staphylococcus aureus and Pseudomonas sp. and showed excellent cell viability (>97 %) in Vero cell line. Finally, an in vivo mouse model study showed 99.7 % contraction (p < .05) within 12 days, which was most effectual and 12 % faster than conventional gauge bandages. These results demonstrated the promising and cost-effective potential of the prepared film for wound healing.

Accelerating Full-Thickness Wound Healing with Bacterial Cellulose-Based Multilayer Composites

Materials that speed up wound healing can be of great benefit to patients and healthcare providers. One-layer dressings, however, have unsatisfactory healing efficacy since it is impossible to use materials with different properties simultaneously, and drug delivery is limited by the depth of penetration. The present study utilized a multilayer wound dressing composed of bacterial cellulose (BC) hydrogel, gelatin/alginate (Gel/Alg) hydrogel, and polycaprolactone (PCL) nanofibers loaded with ciprofloxacin (CIP) to promote the healing process in vivo. The designed dressings showed significant water absorption and sufficient water vapor transmission rate (WVTR) after one week, confirming their ability to absorb wound exudate. Within the first four hours, significant amounts of CIP were released from the drug-containing dressing. Then, between hours 4 and 24, the rate decreased and plateaued on day 9. Both positive and negative bacterial strains were inhibited by the gradual release of CIP, while fibroblasts retained their normal morphology and metabolic activity. Lastly, in vivo tests demonstrated that CIP-loaded multilayer dressings could significantly speed up full-thickness wound healing during 14 days, by reducing inflammation, stimulating re-epithelialization, and enhancing skin regeneration. Our findings indicate that multilayering BC hydrogels with drug-loaded nanofibers provide a promising way to promote wound healing by utilizing all the distinctive properties of these layers.

Electrospun zein nanofibers loaded with curcumin as a wound dressing: enhancing properties with PSS and PDADMAC layers

Development of wound dressings with enhanced therapeutic properties is of great interest in the modern healthcare. In this study, a zein-based nanofibrous wound dressing containing curcumin as a therapeutic agent was fabricated through electrospinning technique. In order to achieve desirable properties, such as antibacterial characteristics, reduced contact angle, and enhanced mechanical properties, the layer-by-layer technique was used for coating the surfaces of drug-loaded nanofibers by sequentially incorporating poly (sodium 4-styrene sulfonate) as a polyanion and poly (diallyldimethylammonium chloride) (PDADMAC) as a polycation. Various analyses, including scanning electron microscopy, Fourier transform infrared spectroscopy, drug release assessment., and mechanical tests were employed to assess the characteristics of the prepared wound dressings. Based on the results, coating with polyelectrolytes enhanced the Young's modulus and tensile strength of the electrospun mat from 1.34 MPa and 4.21 MPa to 1.88 MPa and 8.83 MPa, respectively. The coating also improved the controlled release of curcumin and antioxidant activity, while the outer layer, PDADMAC, exhibited antibacterial properties. The cell viability tests proved the appropriate biocompatibility of the prepared wound dressings. Moreover, our findings show that incorporation of the coating layers enhances cell migration and provides a favorable surface for cell attachment. According to the findings of this study, the fabricated nanofibrous wound dressing can be considered a promising and effective therapeutic intervention for wound management, facilitating the healing process.

Fucoidan loaded PVA/Dextran blend electrospun nanofibers for the effective wound healing

Chronic wounds have become a serious global health issue. In this study, we investigated the effect of increasing fucoidan (FD) concentration on the characteristics of nanofibers and their wound healing potential at in vitro as well as in vivo level. The results showed that increasing FD content (0.25 to 1 %) led to an significant increase in nanofiber diameter (487.7 ± 125.39 to 627.9 ± 149.78 nm), entrapment efficiency (64.26 ± 2.6 to 94.9 ± 3.1 %), and water uptake abilities (436.5 ± 1.2 to 679.7 ± 11.3 %). However, the in vitro biodegradation profile decreased with an increase in FD concentration. Water vapor transmission rate analysis showed that it was within the standard range for all FD concentrations. Nanofibers with 1 % PVA/DX/FD exhibited slow-release behavior, suggesting prolonged FD availability at the wound site. In vivo studies in rats with full-thickness wounds demonstrated that applying 1 % FD-enriched PVA/DEX nanofibers significantly (p < 0.0001) improved mean wound area closure. These findings suggest that FD-enriched nanofibers have immense potential as a wound dressing material in future if explored further.

Preparation of nanocellulose and its applications in wound dressing: A review

Nanocellulose, as a nanoscale polymer material, has garnered significant attention worldwide due to its numerous advantages including excellent biocompatibility, thermal stability, non-toxicity, large specific surface area, and good hydrophilicity. Various methods can be employed for the preparation of nanocellulose. Traditional approaches such as mechanical, chemical, and biological methods possess their own distinct characteristics and limitations. However, with the growing deterioration of our living environment, several green and environmentally friendly preparation techniques have emerged. These novel approaches adopt eco-friendly technologies or employ green reagents to achieve environmental sustainability. Simultaneously, there is a current research focus on optimizing traditional nanocellulose preparation methods while addressing their inherent drawbacks. The combination of mechanical and chemical methods compensates for the limitations associated with using either method alone. Nanocellulose is widely used in wound dressings owing to its exceptional properties, which can accelerate the wound healing process and reduce patient discomfort. In this paper, the principle, advantages and disadvantages of each preparation method of nanocellulose and the research findings in recent years are introduced Moreover, this review provides an overview of the utilization of nanocellulose in wound dressing applications. Finally, the prospective trends in its development alongside corresponding preparation techniques are discussed.

Three-Dimensional Printed Cellulose for Wound Dressing Applications

Wounds are skin tissue damage due to trauma. Many factors inhibit the wound healing phase (hemostasis, inflammation, proliferation, and alteration), such as oxygenation, contamination/infection, age, effects of injury, sex hormones, stress, diabetes, obesity, drugs, alcoholism, smoking, nutrition, hemostasis, debridement, and closing time. Cellulose is the most abundant biopolymer in nature which is promising as the main matrix of wound dressings because of its good structure and mechanical stability, moisturizes the area around the wound, absorbs excess exudate, can form elastic gels with the characteristics of bio-responsiveness, biocompatibility, low toxicity, biodegradability, and structural similarity with the extracellular matrix (ECM). The addition of active ingredients as a model drug helps accelerate wound healing through antimicrobial and antioxidant mechanisms. Three-dimensional (3D) bioprinting technology can print cellulose as a bioink to produce wound dressings with complex structures mimicking ECM. The 3D printed cellulose-based wound dressings are a promising application in modern wound care. This article reviews the use of 3D printed cellulose as an ideal wound dressing and their properties, including mechanical properties, permeability aspect, absorption ability, ability to retain and provide moisture, biodegradation, antimicrobial property, and biocompatibility. The applications of 3D printed cellulose in the management of chronic wounds, burns, and painful wounds are also discussed.

20(R)-ginsenoside Rg3-loaded polyurethane/marine polysaccharide based nanofiber dressings improved burn wound healing potentials

The management of deep burn injuries is extremely challenging, ascribed to their delayed wound healing rate, susceptibility for bacterial infections, pain, and increased risk of hypertrophic scarring. In our current investigation, a series of composite nanofiber dressings (NFDs) based on polyurethane (PU) and marine polysaccharides (i.e., hydroxypropyl trimethyl ammonium chloride chitosan, HACC and sodium alginate, SA) were accomplished by electrospinning and freeze-drying protocols. The 20(R)-ginsenoside Rg3 (Rg3) was further loaded into these NFDs to inhibit the formation of excessive wound scars. The PU/HACC/SA/Rg3 dressings showed a sandwich-like structure. The Rg3 was encapsulated in the middle layers of these NFDs and slowly released over 30 days. The PU/HACC/SA and PU/HACC/SA/Rg3 composite dressings demonstrated superior wound healing potentials over other NFDs. These dressings also displayed favorable cytocompatibility with keratinocytes and fibroblasts and could dramatically accelerate epidermal wound closure rate following 21 days of the treatment of a deep burn wound animal model. Interestingly, the PU/HACC/SA/Rg3 obviously reduced the excessive scar formation, with a collagen type I/III ratio closer to the normal skin. Overall, this study represented PU/HACC/SA/Rg3 as a promising multifunctional wound dressing, which promoted the regeneration of burn skins and attenuated scar formation.

Fabrication and characterization of antimicrobial wound dressing nanofibrous materials by PVA-betel leaf extract

This present study involves the formation and investigation of the characteristics of a fabricated mat from a PVA-betel leaf mixture. Under ideal processing parameters, nanofibrous mat is synthesized from the PVA-betel leaf blended solution by using the electrospinning technique. Afterwards, the produced nanofibrous mat is assessed for its thermal, antibacterial, morphological, moisture management and chemical interaction behavior using thermogravimetric analysis (TGA), antibacterial assay, scanning electron microscope (SEM), moisture management tester (MMT) and Fourier-transform infrared spectroscopy (FTIR) respectively. The antibacterial action against Staphylococcus aureus and Escherichia coli bacteria has been assessed using the agar diffusion technique, which reveals the creation of zones of inhibition with a value of about 20 mm. Besides, the fabricated nanomat reveals an average diameter of 183.4 nm with improved moisture and thermal characteristics. Furthermore, the generated nanofibrous mat has all the necessary components, as evidenced by the distinctive peaks in the FTIR spectra. Hence, the recently developed nanofibrous mat exhibits promising potential as a suitable material for wound dressing applications.

Perspectives of nanofibrous wound dressings based on glucans and galactans - A review

Wound healing is a complex and dynamic process that needs an appropriate environment to overcome infection and inflammation to progress well. Wounds lead to morbidity, mortality, and a significant economic burden, often due to the non-availability of suitable treatments. Hence, this field has lured the attention of researchers and pharmaceutical industries for decades. As a result, the global wound care market is expected to be 27.8 billion USD by 2026 from 19.3 billion USD in 2021, at a compound annual growth rate (CAGR) of 7.6 %. Wound dressings have emerged as an effective treatment to maintain moisture, protect from pathogens, and impede wound healing. However, synthetic polymer-based dressings fail to comprehensively address optimal and quick regeneration requirements. Natural polymers like glucan and galactan-based carbohydrate dressings have received much attention due to their inherent biocompatibility, biodegradability, inexpensiveness, and natural abundance. Also, nanofibrous mesh supports better proliferation and migration of fibroblasts because of their large surface area and similarity to the extracellular matrix (ECM). Thus, nanostructured dressings derived from glucans and galactans (i.e., chitosan, agar/agarose, pullulan, curdlan, carrageenan, etc.) can overcome the limitations associated with traditional wound dressings. However, they require further development pertaining to the wireless determination of wound bed status and its clinical assessment. The present review intends to provide insight into such carbohydrate-based nanofibrous dressings and their prospects, along with some clinical case studies.

Applications and perspectives of quaternized cellulose, chitin and chitosan: A review

Recently, increasing attention has been paid to natural polysaccharides for their low cost, biocompatibility and biodegradability. Quaternization is a modification method to improve the solubility and antibacterial ability of natural polysaccharides. Water-soluble derivatives of cellulose, chitin and chitosan offer the prospect of diverse applications in a wide range of fields, such as antibacterial products, drug delivery, wound healing, sewage treatment and ion exchange membranes. By combining the inherent properties of cellulose, chitin and chitosan with the inherent properties of the quaternary ammonium groups, new products with multiple functions and properties can be obtained. In this review, we summarized the research progress in the applications of quaternized cellulose, chitin and chitosan in recent five years. Moreover, ubiquitous challenges and personal perspectives on the further development of this promising field are also discussed.

A review on polysaccharides mediated electrospun nanofibers for diabetic wound healing: Their current status with regulatory perspective

The current treatment strategies for diabetic wound care provide only moderate degree of effectiveness; hence new and improved therapeutic techniques are in great demand. Diabetic wound healing is a complex physiological process that involves synchronisation of various biological events such as haemostasis, inflammation, and remodelling. Nanomaterials like polymeric nanofibers (NFs) offer a promising approach for the treatment of diabetic wounds and have emerged as viable options for wound management. Electrospinning is a powerful and cost-effective method to fabricate versatile NFs with a wide array of raw materials for different biological applications. The electrospun NFs have unique advantages in the development of wound dressings due to their high specific surface area and porosity. The electrospun NFs possess a unique porous structure and biological function similar to the natural extracellular matrix (ECM), and are known to accelerate wound healing. Compared to traditional dressings, the electrospun NFs are more effective in healing wounds owing to their distinct characteristics, good surface functionalisation, better biocompatibility and biodegradability. This review provides a comprehensive overview of the electrospinning procedure and its operating principle, with special emphasis on the role of electrospun NFs in the treatment of diabetic wounds. This review discusses the present techniques applied in the fabrication of NF dressings, and highlights the future prospects of electrospun NFs in medicinal applications.

Scientometric Research on Trend Analysis of Nano-Based Sustained Drug Release Systems for Wound Healing

Nanomaterials, such as the nanoparticle (NP), nanomicelle, nanoscaffold, and nano-hydrogel, have been researched as nanocarriers for drug delivery more and more recently. Nano-based drug sustained release systems (NDSRSs) have been used in many medical fields, especially wound healing. However, as we know, no scientometric analysis has been seen on applying NDSRSs in wound healing, which could be of great importance to the relevant researchers. This study collected publications from 1999 to 2022 related to NDSRSs in wound healing from the Web of Science Core Collection (WOSCC) database. We employed scientometric methods to comprehensively analyze the dataset from different perspectives using CiteSpace, VOSviewer, and Bibliometrix. The results indicated that China published the most significant number of documents in the last two decades, Islamic Azad Univ was the most productive institution, and Jayakumar, R was the most influential author. Regarding the analysis of keywords, trend topics indicate that "antibacterial", "chitosan (CS)", "scaffold", "hydrogel", "silver nanoparticle", and "growth factors (GFs)" are the hot topics in recent years. We anticipate that our work will provide a comprehensive overview of research in this field and help scholars better understand the research hotspots and frontiers in this area, thus inspiring further explorations in the future.

PLA and PBAT-Based Electrospun Fibers Functionalized with Antibacterial Bio-Based Polymers

Antimicrobial fibers based on biodegradable polymers, poly(lactic acid) (PLA), and poly(butylene adipate-co-terephthalate) (PBAT) are prepared by electrospinning. For this purpose, a biodegradable/bio-based polyitaconate containing azoles groups (PTTI) is incorporated at 10 wt.% into the electrospinning formulations. The resulting fibers functionalized with azole moieties are uniform and free of beads. Then, the accessible azole groups are subjected to N-alkylation, treatment that provides cationic azolium groups with antibacterial activity at the surface of fibers. The positive charge density, roughness, and wettability of the cationic fibers are evaluated and compared with flat films. It is confirmed that these parameters exert an important effect on the antimicrobial properties, as well as the length of the alkylating agent and the hydrophobicity of the matrix. The quaternized PLA/PTTI fibers exhibit the highest efficiency against the tested bacteria, yielding a 4-Log reduction against S. aureus and 1.7-Log against MRSA. Then, biocompatibility and bioactivity of the fibers are evaluated in terms of adhesion, morphology and viability of fibroblasts. The results show no cytotoxic effect of the samples, however, a cytostatic effect is appreciated, which is ascribed to the strong electrostatic interactions between the positive charge at the fiber surface and the negative charge of the cell membranes.

Rational design of biodegradable thermoplastic polyurethanes for tissue repair

As a type of elastomeric polymers, non-degradable polyurethanes (PUs) have a long history of being used in clinics, whereas biodegradable PUs have been developed in recent decades, primarily for tissue repair and regeneration. Biodegradable thermoplastic (linear) PUs are soft and elastic polymeric biomaterials with high mechanical strength, which mimics the mechanical properties of soft and elastic tissues. Therefore, biodegradable thermoplastic polyurethanes are promising scaffolding materials for soft and elastic tissue repair and regeneration. Generally, PUs are synthesized by linking three types of changeable blocks: diisocyanates, diols, and chain extenders. Alternating the combination of these three blocks can finely tailor the physio-chemical properties and generate new functional PUs. These PUs have excellent processing flexibilities and can be fabricated into three-dimensional (3D) constructs using conventional and/or advanced technologies, which is a great advantage compared with cross-linked thermoset elastomers. Additionally, they can be combined with biomolecules to incorporate desired bioactivities to broaden their biomedical applications. In this review, we comprehensively summarized the synthesis, structures, and properties of biodegradable thermoplastic PUs, and introduced their multiple applications in tissue repair and regeneration. A whole picture of their design and applications along with discussions and perspectives of future directions would provide theoretical and technical supports to inspire new PU development and novel applications.

Development of SiC-TiO2-Graphene neem extracted antimicrobial nano membrane for enhancement of multiphysical properties and future prospect in dental implant applications

This paper presents the coating technology on Nano membrane using SiC-TiO2-Graphene with varying percentages of Azadirachta indica (Neem) extract with an objective to develop new coating materials. The nanomembranes have been synthesized by electrospinning machine over aluminum foil paper using the raw materials PVA grain, SiC, TiO2, Graphene, and neem. The nanomembranes have been characterized by SEM, XRD, FTIR, Surface Roughness, antibacterial, and Cytotoxicity test. FTIR analysis established the presence of PVA and neem indicating the formation of different organic compounds. It also confirmed that no chemical reaction occurred during the synthesis process. The membrane's roughness analysis obtained average roughness values from 1.15 to 3.84. The formation of homogeneous and smooth membranes with the formation of micropores was confirmed by SEM analysis. Miller Indices identified different types of crystal structures in XRD analysis. Antibacterial activity increased with the increase of the percentage of neem confirmed by the antibacterial test. No toxic effects were observed from the membrane during the cytotoxicity test. The obtained data confirmed that the synthesized nanomembrane could be used in different biomedical applications.

Comparison of Nozzle-Based and Nozzle-Free Electrospinning for Preparation of Fast-Dissolving Nanofibers Loaded with Ciprofloxacin

The study aimed to prepare ciprofloxacin-loaded polyvinylpyrrolidone electrospun nanofibers for oral drug delivery, using a conventional nozzle-based and a lab-built nozzle-free electrospinning equipment. To produce nanofibers, electrospinning is the process most often used. However, from the industry’s point of view, conventional electrospinning does not have sufficiently high productivity. By omitting the nozzle, productivity can be increased, and so the development of nozzle-free processes is worthwhile. In this study, a solution of ciprofloxacin and polyvinylpyrrolidone was electrospun under similar conditions, using both single-nozzle and nozzle-free methods. The two electrospinning methods were compared by investigating the morphological and physicochemical properties, homogeneity, in vitro drug release, and cytotoxicity. The stability of the nanofibers was monitored from different aspects in a 26 month stability study. The results showed that the use of the nozzle-free electrospinning was preferable due to a higher throughput, improved homogeneity, and the enhanced stability of nanofiber mats, compared to the nozzle-based method. Nevertheless, fast dissolving nanofibers loaded with poorly water-soluble ciprofloxacin were produced by both electrospinning methods. The beneficial properties of these nanofibers can be exploited in innovative drug development; e.g., nanofibers can be formulated into orodispersible films or per os tablets.

Polyurethane based hybrid ciprofloxacin-releasing wound dressings designed for skin engineering purpose

PURPOSE

Even in the 21st century, chronic wounds still pose a major challenge due to potentially inappropriate treatment options, so the latest wound dressings are hybrid systems that enable clinical management, such as a hybrid of hydrogels, antibiotics and polymers. These wound dressings are mainly used for chronic and complex wounds, which can easily be infected by bacteria.

MATERIALS AND METHODS

Six Composite Porous Matrices (CPMs) based on polyurethane (PUR) in alliance with polylactide (PLAs) and poly(vinyl alcohol) (PVA) were prepared and analyzed using optical microscopy. Three different types of hydrogels and their Ciprofloxacin (Cipro) modified variants' ratios were prepared and analyzed using FTIR, SEM and EDX techniques. Six Hybrid Cipro-Releasing Hydrogel Wound Dressings (H-CRWDs) were also prepared and underwent short-term degradation, Cipro release, microbiology and cell viability measurements.

RESULTS

Average porosity of CPMs was in the range of 69-81%. The pore size of the obtained CPMs was optimal for skin regeneration. Short-term degradation studies revealed degradability in physiological conditions regardless of sample type. A meaningful release was also observed even in short time (21.76 ​± ​0.64 ​μg/mL after 15 ​min). Microbiological tests showed visible inhibition zones. Cell viability tests proved that the obtained H-CRWDs were biocompatible (over 85% of cells).

CONCLUSIONS

A promising hybrid wound dressing was labeled. Simple and cost-effective methods were used to obtain microbiologically active and biocompatible dressings. The results were of importance for the design and development of acceptable solutions in the management of chronic wounds of high potential for infection.

Hyaluronic Acid-Based Nanomaterials as a New Approach to the Treatment and Prevention of Bacterial Infections

Bacterial contamination of medical devices is a great concern for public health and an increasing risk for hospital-acquired infections. The ongoing increase in antibiotic-resistant bacterial strains highlights the urgent need to find new effective alternatives to antibiotics. Hyaluronic acid (HA) is a valuable polymer in biomedical applications, partly due to its bactericidal effects on different platforms such as contact lenses, cleaning solutions, wound dressings, cosmetic formulations, etc. Because the pure form of HA is rapidly hydrolyzed, nanotechnology-based approaches have been investigated to improve its clinical utility. Moreover, a combination of HA with other bactericidal molecules could improve the antibacterial effects on drug-resistant bacterial strains, and improve the management of hard-to-heal wound infections. This review summarizes the structure, production, and properties of HA, and its various platforms as a carrier in drug delivery. Herein, we discuss recent works on numerous types of HA-based nanoparticles to overcome the limitations of traditional antibiotics in the treatment of bacterial infections. Advances in the fabrication of controlled release of antimicrobial agents from HA-based nanosystems can allow the complete eradication of pathogenic microorganisms.

Antibacterial biomaterials for skin wound dressing

Bacterial infection and the ever-increasing bacterial resistance have imposed severe threat to human health. And bacterial contamination could significantly menace the wound healing process. Considering the sophisticated wound healing process, novel strategies for skin tissue engineering are focused on the integration of bioactive ingredients, antibacterial agents included, into biomaterials with different morphologies to improve cell behaviors and promote wound healing. However, a comprehensive review on anti-bacterial wound dressing to enhance wound healing has not been reported. In this review, various antibacterial biomaterials as wound dressings will be discussed. Different kinds of antibacterial agents, including antibiotics, nanoparticles (metal and metallic oxides, light-induced antibacterial agents), cationic organic agents, and others, and their recent advances are summarized. Biomaterial selection and fabrication of biomaterials with different structures and forms, including films, hydrogel, electrospun nanofibers, sponge, foam and three-dimension (3D) printed scaffold for skin regeneration, are elaborated discussed. Current challenges and the future perspectives are presented in this multidisciplinary field. We envision that this review will provide a general insight to the elegant design and further refinement of wound dressing.

Biocompatible Nanomaterials for Burns

Abstract:

Skin being the largest organ protects our body against harmful chemicals, pathogens and physical agents. It constitutes three primarily layers - epidermis, dermis and the subcutaneous layers. Injuries occurring due to burn remains localized to skin or other organic tissues caused by flame, extreme heat, and close contact with chemicals or heated objects. Conventional treatments are available for treatment of burns however they are expensive and might completely replaces autologous tissue transfer completely. Nanotechnology based approaches include organic nanoparticles, dendrimers, hydrogels, etc. Biocompatibility usually refer ability of biomaterial of performing their respective functions centred towards medical therapy, without causing any systemic or local effects. Polymeric materials like natural (chitosan, hyaluronic acid) and synthetic (polylactic acid, polycaprolactone) are employed as biomaterials. Various preclinical and clinical studies were performed in animal models. In this review, authors have discussed elaborately on the biocompatible polymers which are used in treatment of burn wounds. Afternath, a brief discussion on the polymers, pre-clinical and clinical studies, regulatory concern related to nanomaterials also had been covered.

ZnO nanostructured materials and their potential applications: progress, challenges and perspectives

Extensive research in nanotechnology has been conducted to investigate new behaviours and properties of materials with nanoscale dimensions. ZnO NPs owing to their distinct physical and chemical properties have gained considerable importance and are hence investigated to a detailed degree for exploitation of these properties. This communication, at the outset, elaborates the various chemical methods of preparation of ZnO NPs, viz., the mechanochemical process, controlled precipitation, sol-gel method, vapour transport method, solvothermal and hydrothermal methods, and methods using emulsion and micro-emulsion environments. The paper further describes the green methods employing the use of plant extracts, in particular, for the synthesis of ZnO NPs. The modifications of ZnO with organic (carboxylic acid, silanes) and inorganic (metal oxides) compounds and polymer matrices have then been described. The multitudinous applications of ZnO NPs across a variety of fields such as the rubber industry, pharmaceutical industry, cosmetics, textile industry, opto-electronics and agriculture have been presented. Elaborative narratives on the photocatalytic and a variety of biomedical applications of ZnO have also been included. The ecotoxic impacts of ZnO NPs have additionally been briefly highlighted. Finally, efforts have been made to examine the current challenges and future scope of the synthetic modes and applications of ZnO NPs.

Bi-layered disulfiram-loaded fiber membranes with antibacterial properties for wound dressing

In this study, the bi-layered disulfiram-loaded fiber membranes with the antibacterial activity and different surface wettabilities are prepared using electrospinning technology. In the application of wound dressing, the hydrophilic surface of fiber membranes is beneficial for cell adhesion and drug release to heal the wound. Meanwhile, the outside hydrophobic surface is able to block water penetration to reduce the probability of wound infection. The obtained bi-layered drug-loaded fiber membranes are composed of polyvinylidene fluoride (PVDF) bottom surface and disulfiram (DSF)/polylactic acid (PLA) top surface. To modify the top surface wettability, the oxygen plasma modification of bi-layered membranes was carried out. The morphology, wettability, and chemical compositions of bi-layered drug-loaded fiber membranes were analyzed using the scanning electronic microscope (SEM), drop shape analysis instrument, X-ray diffractometer (XRD), and X-ray photoelectron spectrometer (XPS). The bi-layered disulfiram-loaded membranes showed the potent antibacterial activity in vitro against both Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). It was found that the bi-layered membranes had good biocompatibility with L929 cells. Thus, the obtained bi-layered disulfiram-loaded fiber membranes are suitable for wound dressing application.

Fabrication of Biohybrid Nanofibers by the Green Electrospinning Technique and Their Antibacterial Activity

The development of bioactive polymer nanofiber sheets based on eco-friendly components is required to meet the needs of various medical applications as well as to preserve the environment. This study aimed to fabricate biohybrid nanofibers based on water-soluble polymers and aqueous extract of myrrh. The myrrh extract was incorporated into poly(vinyl alcohol)/tragacanth gum nanofiber mats (myrrh@PVA/TG) by the green electrospinning technique. Various characteristics of the prepared fibers such as morphology, fiber diameter distribution, crystallinity, and thermal stability were studied. The results confirmed that the morphology of biohybrid nanofibers was uniform without beads and tragacanth gum plays an important role in controlling the average diameter of fibers and the crystallinity. The antibacterial properties of the developed biohybrid nanofibers were investigated against common pathogens of Gram-positive and Gram-negative bacteria by the standard disc diffusion method. A significant antibacterial activity was observed toward bacterial strains after incorporation of aqueous myrrh extract into nanofibers, which increased on increasing the extract ratio. Due to their eco-friendly components and significant antibacterial activity, the prepared biohybrid nanofibers will open new avenues toward incorporating aqueous herbal extracts into degradable polymer fibers for use in many antibacterial applications.

Dextran, as a biological macromolecule for the development of bioactive wound dressing materials: A review of recent progress and future perspectives

Skin is the largest organ in the body which plays different roles in maintaining hemostasis. Although this tissue has a high healing potential, severe skin wounds cannot heal without external interventions. Among various treatment strategies, tissue-engineered wound dressings have gained significant attention. In this regard, tremendous progress has been made in the field of tissue engineering to develop constructs with higher healing activities. Material selection and optimization are key factors in development of such dressings. Among different candidates, dextran-based wound dressings have been extensively studied. Dextran is a branched biological macromolecule which is composed of anhydroglucose monomers. Due to its excellent biocompatibility, biodegradability, non-toxicity, modifiable functional groups, and proven clinical safety, dextran has found application in wound healing research. In the current review, applications, challenges, and future perspectives of dextran-based wound dressings will be discussed.

Cationic, anionic and neutral polysaccharides for skin tissue engineering and wound healing applications

Today, chronic wound care and management can be regarded as a clinically critical issue. However, the limitations of current approaches for wound healing have encouraged researchers and physicians to develop more efficient alternative approaches. Advances in tissue engineering and regenerative medicine have resulted in the development of promising approaches that can accelerate wound healing and improve the skin regeneration rate and quality. The design and fabrication of scaffolds that can address the multifactorial nature of chronic wound occurrence and provide support for the healing process can be considered an important area requiring improvement. In this regard, polysaccharide-based scaffolds have distinctive properties such as biocompatibility, biodegradability, high water retention capacity and nontoxicity, making them ideal for wound healing applications. Their tunable structure and networked morphology could facilitate a number of functions, such as controlling their diffusion, maintaining wound moisture, absorbing a large amount of exudates and facilitating gas exchange. In this review, the wound healing process and the influential factors, structure and properties of carbohydrate polymers, physical and chemical crosslinking of polysaccharides, scaffold fabrication techniques, and the use of polysaccharide-based scaffolds in skin tissue engineering and wound healing applications are discussed.

Functionalized Antimicrobial Nanofibers: Design Criteria and Recent Advances

The rise of antibiotic resistance has become a major threat to human health and it is spreading globally. It can cause common infectious diseases to be difficult to treat and leads to higher medical costs and increased mortality. Hence, multifunctional polymeric nanofibers with distinctive structures and unique physiochemical properties have emerged as a neo-tool to target biofilm and overcome deadly bacterial infections. This review emphasizes electrospun nanofibers' design criteria and properties that can be utilized to enhance their therapeutic activity for antimicrobial therapy. Also, we present recent progress in designing the surface functionalization of antimicrobial nanofibers with non-antibiotic agents for effective antibacterial therapy. Lastly, we discuss the future trends and remaining challenges for polymeric nanofibers.

Improved wound healing of diabetic foot ulcers using human placenta-derived mesenchymal stem cells in gelatin electrospun nanofibrous scaffolds plus a platelet-rich plasma gel: A randomized clinical trial

AIM

The effectiveness of nanofibers containing human placenta-derived mesenchymal stem cells (hPDMSCs) plus platelet-rich plasma (PRP) for healing of diabetic foot ulcers (DFUs) was investigated.

METHODS

hPDMSCs were isolated from human donor placentas, and cultured in electrospun gelatin nanofibrous scaffolds (GNS). Twenty-eight patients with DFUs were randomized into three groups in a 12-week trial: (A) Treated with hPDMSCs; (B) Treated with hPDMSCs after coating the ulcer with PRP gel; (C) Control group received standard wound care. Wound area and pain freewalkingdistance were measured every 2 weeks.

RESULTS

Flow cytometry showed the expression of mesenchymal markers. SEM images and DAPI staining indicated significantly higher levels of hPDMSC proliferation on GNS after 3 and 7 days of culture. The MTS assay showed a significant increase in proliferation on GNS, compared to controls. Wound size reduction was 66% in group A, 71% in group B, and 36% in control group C. A significant difference in wound closure and pain-free walking distance was observed between groups A and B, compared to control group C (p < 0.05), but no difference between groups A and B. Biopsy of the implanted tissue showed the development of new capillary formation in groups A and B.

CONCLUSION

Implantation of hPDMSCs in GNS accelerated wound healing and improved clinical parameters in DFU patients.

Research progress, models and simulation of electrospinning technology: a review

In recent years, nanomaterials have aroused extensive research interest in the world's material science community. Electrospinning has the advantages of wide range of available raw materials, simple process, small fiber diameter and high porosity. Electrospinning as a nanomaterial preparation technology with obvious advantages has been studied, such as its influencing parameters, physical models and computer simulation. In this review, the influencing parameters, simulation and models of electrospinning technology are summarized. In addition, the progresses in applications of the technology in biomedicine, energy and catalysis are reported. This technology has many applications in many fields, such as electrospun polymers in various aspects of biomedical engineering. The latest achievements in recent years are summarized, and the existing problems and development trends are analyzed and discussed.

Biomedical Applications of Nanofibers

The idea of creating replacement for damaged or diseased tissue, which will mimic the physiological conditions and simultaneously promote regeneration by patients’ own cells, has been a major challenge in the biomedicine for more than a decade. Therefore, nanofibers are a promising solution to address these challenges. Nanofiber technology is an exciting area attracting the attention of many researchers as a potential solution to these current challenges in the biomedical field such as burn and wound care, organ repair, and treatment for osteoporosis and various diseases. Nanofibers mimic the porous topography of natural extracellular matrix (ECM), hence they are advantageous for tissue regeneration . In biomedical engineering, electrospinning exhibits advantages as a tissue engineering scaffolds producer, which can make appropriate resemblance in physical structure with ECM. This is because of the nanometer scale of ECM fibrils in diameter, which can be mimicked by electrospinning procedure as well as its porous structure. In this review, the applications of nanofibers in various biomedical areas such as tissue engineering, wound dressing and facemask, are summarized. It provides opportunities to develop new materials and techniques that improve the ability for developing quick, sensitive and reliable analytical techniques.

Polymer-Based Nanotherapeutics for Burn Wounds

Burn wounds are complex and intricate injuries that have become a common cause of trauma leading to significant mortality and morbidity every year. Dressings are applied to burn wounds with the aim of promoting wound healing, preventing burn infection and restoring skin function. The dressing protects the injury and contributes to recovery of dermal and epidermal tissues. Polymer-based nanotherapeutics are increasingly being exploited as burn wound dressings. Natural polymers such as cellulose, chitin, alginate, collagen, gelatin and synthetic polymers like poly (lactic-co-glycolic acid), polycaprolactone, polyethylene glycol, and polyvinyl alcohol are being obtained as nanofibers by nanotechnological approaches like electrospinning and have shown wound healing and re-epithelialization properties. Their biocompatibility, biodegradability, sound mechanical properties and unique structures provide optimal microenvironment for cell proliferation, differentiation, and migration contributing to burn wound healing. The polymeric nanofibers mimic collagen fibers present in extracellular matrix and their high porosity and surface area to volume ratio enable increased interaction and sustained release of therapeutics at the site of thermal injury. This review is an attempt to compile all recent advances in the use of polymer-based nanotherapeutics for burn wounds. The various natural and synthetic polymers used have been discussed comprehensively and approaches being employed have been reported. With immense research effort that is currently being invested in this field and development of proper characterization and regulatory framework, future progress in burn treatment is expected to occur. Moreover, appropriate preclinical and clinical research will provide evidence for the great potential that polymer-based nanotherapeutics hold in the management of burn wounds.