Nanofibrous Dressings Research Articles

Kaolin-loaded chitosan/polyvinyl alcohol electrospun scaffold as a wound dressing material: in vitro and in vivo studies.

To evaluate the application of a fabricated dressing containing kaolin for skin regeneration in a rat model of excisional wounds. In the present study, kaolin was loaded into electrospun polyvinyl alcohol (PVA)/chitosan polymer blend to develop a composite nanofibrous dressing. To make the yarns, kaolin with weight ratio of 5% was added to PVA/chitosan polymer blend and subsequently formed into nanofibres using the electrospinning method. Scaffolds were evaluated for to their microstructure, mechanical properties, surface wettability, water vapour transmission rate, water-uptake capacity, blood uptake capacity, blood compatibility, microbial penetration test, the number of colonies, and cellular response with the L929 cell line. Rats with full-thickness excisional wounds were treated with kaolin-containing and kaolin-free dressings. The study showed that rats treated with the kaolin-incorporated mats demonstrated a significant closure to nearly 97.62±4.81% after 14 days compared with PVA/chitosan and the sterile gauze, which showed 86.15±8.11% and 78.50±4.22% of wound closure, respectively. The histopathological studies showed that in the PVA/chitosan/kaolin group, dense and regular collagen fibres were formed, while wounds treated with sterile gauze or PVA/chitosan scaffolds had random and loose collagen fibres. Our results show the potential applicability of PVA/chitosan/kaolin scaffolds as a wound care material.

Oxygen Generating Polymeric Nano Fibers That Stimulate Angiogenesis and Show Efficient Wound Healing in a Diabetic Wound Model.

IntroductionDiabetic wounds are challenging to treat due to a wide range of pathophysiological changes. Hypoxia is one of the predominant contributing factors of poor vascularization and chronicity in diabetic wounds. This study was designed to develop polycaprolactone (PCL)-based oxygen-releasing electrospun wound dressings and evaluate their efficacy for improved full thickness wound healing in diabetic rats.MethodsPCL-based oxygen releasing wound dressings were made using electrospinning technology. The developed dressings were characterized in terms of physical as well as biological properties both in vitro and in vivo. E-spun nanofibrous dressings were physically characterized with scanning electron microscopy, Fourier-transform infrared spectroscopy, and Energy-dispersive X-ray spectroscopy. To study the likely impact of the fabricated wound dressings in hypoxic conditions, HIF-1α expression analysis was carried out both at gene and protein levels. Wound dressings were further evaluated for their healing potential for extensive wounds in diabetic rat models.ResultsThe experimental results showed that the developed dressings were capable of continuously generating oxygen for up to 10 days. Cell studies further confirmed pronounced expression of HIF-1α at gene and protein levels in cells seeded on PCL-sodium percarbonate (SPC) and PCL scaffolds compared with the cells cultured on a tissue culture plate. Chorioallantoic membrane assay revealed the supportive role of oxygen releasing dressings on angiogenesis compared to the control group. Histological assessment of the regenerated skin tissues proved that full thickness wounds covered with SPC loaded PCL dressings had a comparatively better vascularized and compact extracellular matrix with completely covered thick epithelium.DiscussionThe developed oxygen generating polymeric nanofibrous wound dressings could potentially be used as an envisioned approach for the efficient recovery of chronic diabetic wounds.

Physicochemical and Antibacterial Characterization of Nanofibrous Wound Dressing from Silk Fibroin-polyvinyl Alcohol- Elaeagnus Angustifolia Extract

The herbal drug incorporated nanofibers with potential accelerating wound healing has become a promising wound dressing to treat wounds. The present research aimed to study the effects of adding different amounts of Elaeagnus Angustifolia (EA) extract on physical, mechanical, and biological properties of silk fibroin-polyvinyl alcohol (SF-PVA) nanofibers. Thus, different electrospun mats were made by changing the SF to the EA ratio. The successful incorporation of EA in SF-PVA nanofibers was confirmed by Fourier transform infrared spectroscopy (FTIR). No obvious change was observed in the mean fiber diameter except for EA/SF ratio 1:3. Also, mechanical properties results showed that the ultimate tensile strength of samples dropped from 9±0.8 MPa to 2.50±0.03 MPa with decreasing SF amount. The in vitro release studies indicated that the fickian diffusion controlled the EA release profile and it was faster in the nanofibers containing more EA. Furthermore, the addition of EA into the nanofibrous dressings improved their antioxidant activity as well as antibacterial activity against both gram-positive (S. aureus) and gram- negative (E. coli) bacteria. Cell viability was also measured using fibroblast cells cultured on prepared dressings and results proved that the higher amounts of EA have a significant impact on cell viability. These findings suggest the advantages of EA as an additive to regulate cell behavior and for skin tissue regeneration.

Human Adipose-Derived Stem Cell Secreted Extracellular Matrix Incorporated into Electrospun Poly(Lactic-co-Glycolic Acid) Nanofibrous Dressing for Enhancing Wound Healing.

Wound dressing, which prevents dehydration and provides a physical barrier against infection to wound beds, can improve wound healing. The interactions between extracellular matrix (ECM) and growth factors is critical to the healing process. Electrospun nanofibers are promising templates for wound dressings due to the structure similarity to ECM of skin. Otherwise, the ECM secreted by human adipose-derived stem cells (hASCs) is rich in growth factors known to enhance wound healing. Accordingly, we propose that the PLGA nanofibrous template incorporated with hASCs-secreted ECM may enhance wound healing. In this study, PLGA nanofibrous matrixes with an aligned or a random structure were prepared by electrospinning. Human ASCs cultured on the aligned matrix had a better viability and produced a larger amount of ECM relative to that of random one. After 7 days’ cultivation, the hASCs on aligned PLGA substrates underwent decellularization to fabricate cECM/PLGA dressings. By using immunohistochemical staining against F-actin and cell nucleus, the removal of cellular components was verified. However, the type I collagen and laminin were well preserved on the cECM/PLGA nanofibrous matrixes. In addition, this substrate was hydrophilic, with appropriate mechanical strength to act as a wound dressing. The L929 fibroblasts had good activity, survival and proliferation on the cECM/PLGA meshes. In addition, the cECM/PLGA nanofibrous dressings improved the wound healing of surgically created full-thickness skin excision in a mouse model. This hASCs-secreted ECM incorporated into electrospun PLGA nanofibrous could be a promising dressing for enhancing wound healing.

Tazarotene Released from Aligned Electrospun Membrane Facilitates Cutaneous Wound Healing by Promoting Angiogenesis.

Wound treatment is a long-lasting clinical issue. Poor angiogenesis leading to delayed wound closure causes huge challenges for healing. Functional electrospun membranes have been established as an efficient strategy to promote wound recovery by protecting and improving vascular regeneration. Here, we aimed to investigate the effect of tazarotene, an active drug for angiogenesis, loaded in aligned electrospun nanofibrous barrier on a soft tissue wound. This aligned membrane was arranged in a single direction, and tazarotene could be released from its nanofibers sustainably. The in vitro study demonstrated that compared with the random drug-loaded or other control groups, the aligned tazarotene-loaded membranes [poly-caprolactone (PCL)/AT] could stimulate proliferation, migration, angiogenesis, and vascular endothelial growth factor secretion and its gene expression of human umbilical vein endothelial cells. Furthermore, the in vivo model showed that the prepared tazarotene-loaded aligned membrane significantly accelerated the speed of healing, improved the neovascularization and re-epithelialization, and inhibited the inflammatory reaction in the wound area. All these results above indicated that the PCL/AT nanofibrous dressing, which could promote angiogenesis because of both stimulation of structure and chemical signals, is a promising wound-caring material.

Poly-ε-caprolactone and polyvinyl alcohol electrospun wound dressings: adhesion properties and wound management of skin defects in rabbits.

Aim: This study evaluates the effect of electrospun dressings in critical sized full-thickness skin defects in rabbits. Materials & methods: Electrospun poly-ε-caprolactone (PCL) and polyvinyl alcohol (PVA) nanofibers were tested in vitro and in vivo. Results: The PCL scaffold supported the proliferation of mesenchymal stem cells, fibroblasts and keratinocytes. The PVA scaffold showed significant swelling, high elongation capacity, limited protein adsorption and stimulation of cells. Nanofibrous dressings improved wound healing compared with the control group in vivo. A change of the PCL dressing every 7days resulted in a decreased epithelial thickness and type I collagen level in the adhesive group, indicating peeling off of the newly formed tissue. In the PVA dressings, the exchange did not affect healing. Conclusion: The results demonstrate the importance of proper dressing exchange.

Composite nanofibrous membranes of PLGA/Aloe vera containing lipid nanoparticles for wound dressing applications

Electrospun nanofibrous dressings present suitable characteristics to be used in wound healing, such as high porosity and high surface area-to-volume ratio. In this study, a wound dressing based on PLGA and Aloe vera containing lipid nanoparticles (NLCs) was developed. NLCs were added in order to add a lipid component that could avoid the adhesion of the dressing to the wound and improve its handling. Membranes with and without NLCs were composed of uniform fibers of about 1 µm in diameter. Their porosity was above 80% and their thickness was about 160 µm. Both dressings showed similar water vapour transmission rate 1100 g/m2day. The formulation containing NLCs presented a higher ultimate tensile strength (2.61 ± 0.46 MPa) and a higher water uptake. Both formulations were biocompatible in vitro. Furthermore, the cell adhesion assay demonstrated that both membranes had a low adherence profile, although it was lower with the dressing containing NLCs. Finally, their efficacy was evaluated in a full thickness wound healing assay conducted in db/db mice, where both enhanced healing similarly. Accordingly, the PLGA-AV-NLC membrane might be a promising strategy for the treatment of chronic wounds, since it improved handling in comparison to the formulation without NLCs.

Biocompatible antimicrobial electrospun nanofibers functionalized with ε-poly-l-lysine

The antimicrobial polypeptide ε-poly(l-lysine) (ε-PL) was electrostatically incorporated to poly(acrylic acid) (PAA)/poly(vinyl alcohol) (PVA) electrospun nanofibers. ε-PL loading and distribution was assessed by infrared spectra, ζ-potential measurements and the primary amino reactive dye fluorescamine. Functionalized fibers with 485 ± 140 nm diameter, could be loaded with 0.57–0.74 g ε-PL (g dressing)−1 that released at a constant rate of 5.4 ± 2.8 mg ε-PL (g dressing day)−1. Such a dressings resulted in two orders of magnitude lower bacterial colonization than non-functionalized PAA-PVA after 14 days of incubation. Bacterial impairment was attributed to the damage of cell membranes and the formation of intracellular reactive oxygen species. ε-PL functionalized nanofibers did not display cytotoxicity to human corneal epithelial cells, HCEpC, in 24 h MTT assays. However, the viability of rapidly growing tumoral HeLa cells decreased >50% under the same conditions. The prepared biocompatible nanofibrous dressings with durable antibacterial activity show potential application as wound dressings and other biomedical uses.

Fabricated approach for an effective wound dressing material based on a natural gum impregnated with Acalypha indica extract

Although acute wounds are common, treatment for a scarless condition remains limited and ineffective as medicated dressings act only as an epidermal coverage and no interdermal interactions happen. This study examined the benefit of Acalypha indica, a traditionally acclaimed plant for wound healing, as a three-dimensional nanofibrous dressing. guar gum, a natural polysaccharide, was chosen as the raw material, in combination with a synthetic copolymer polyvinyl alcohol. A series of polymer blend nanofibers made of 3:7 of 1% wt guar and 10% wt polyvinyl alcohol along with varied ratios of A. indica were prepared using electrospinning. The effect of cross-linking by citric acid on the nanofibers was studied using Fourier transform infrared. A 5% wt A. indica content was optimized in the electrospun solution to get nanosized morphology, roughness, water absorbing capacity, thermal stability, and tensile strength. The composite material was found inhibitory to both Gram-positive and Gram-negative strains as measured by zone of inhibition. The ability of the dressing to support and proliferate human dermal fibroblasts was evaluated by cell proliferation assay and Calcein acetomethyl (AM) staining assay. The results confirmed that the composite dressing could support long-term cell growth in the 9-day cell culture study. The incorporation of A. indica to guar/polyvinyl alcohol composite nanofibers has thus resulted in a wound dressing material with nanosized morphology for mimicking the extracellular matrix, surface roughness for the absorbtion of proteins, swelling capacity for the absorption of exudates, antimicrobial activity for prevention of microbial infections, and cell proliferation activity for the complete wound closure. The electrospun guar/polyvinyl alcohol/ A. indica composite which proved to be a suitable dressing for acute wounds when ascertained in vitro can surely be developed as an ethical plant bioactive wound healant.

1α,25-dihydroxyvitamin D3-eluting nanofibrous dressings induce endogenous antimicrobial peptide expression.

The aim of this study was to develop a nanofiber-based dressing capable of local sustained delivery of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) and augmenting human CAMP induction. Nanofibrous wound dressings containing 1,25(OH)2D3 were successfully prepared by electrospinning, which were examined in vitro, in vivo and ex vivo. 1,25(OH)2D3 was successfully loaded into nanofibers with encapsulation efficiency larger than 90%. 1,25(OH)2D3 showed a sustained release from nanofibers over 4weeks. Treatment of U937 and HaCaT cells with 1,25(OH)2D3-loaded poly(ϵ-caprolactone) nanofibers significantly induced hCAP18/LL37 expression in monocytes and keratinocytes, skin wounds of humanized transgenic mice and artificial wounds of human skin explants. 1,25(OH)2D3 containing nanofibrous dressings could enhance innate immunity by inducing antimicrobial peptide production.

Potential of silk sericin based nanofibrous mats for wound dressing applications

Wound dressing developed using bioactive materials has been a current area of research for treating chronic non-healing wounds owing to its high demand. Here, we report the fabrication and evaluation of nanofibrous matrix based wound dressings using biopolymer poly(vinyl alcohol) (PVA) incorporated with silk sericin (SS). SS extracted from the cocoons of mulberry variety Bombyx mori and non-mulberry variety Antheraea assama has been used to develop two types of blended mats. Herein, SS based nanofibrous dressings fabricated using electrospinning technique were thoroughly characterized and evaluated for wound healing applications. The developed SS based nanofibrous mats ranged from 130 to 160 nm in diameter with micro to nanoporous structure. The dressings were endowed with free radical scavenging capacity, antibacterial activity, swelling capacity, and biocompatibility due to incorporation of SS. Furthermore, murine fibroblasts (L929) and human keratinocytes (HaCaT) cultured on the PVA-SS blended mats showed higher proliferation as compared to pristine PVA mats as observed over a period of 14 days (p ≤ 0.01). The blended mats also showed spread out morphology of cells in comparison to spherical clumps formed on PVA mats. In addition, SS from both silk types exhibited excellent antioxidant potential without hampering the cell viability even under H2O2 driven oxidative stress. Moreover, SS (both types) released from the nanofibrous mats also healed the wounds at thrice the rate of control under in vitro conditions. Furthermore, subcutaneous implantation of nanofibrous mats in mice showed in vivo tolerance of the blended nanofibrous mats observed over four weeks without eliciting any inflammatory reactions to the host tissue. Taken together, the developed silk sericin-based dressings signify an attractive substrate for treatment of chronic wounds like diabetic foot ulcers.

106 Initial Experience with a New Bedside Electrospun Nanofibrous Dressing for Second Degree Burns

106 Initial Experience with a New Bedside Electrospun Nanofibrous Dressing for Second Degree Burns

Starch nanoparticle as a vitamin E-TPGS carrier loaded in silk fibroin-poly(vinyl alcohol)-Aloe vera nanofibrous dressing.

Core-sheath nanofibrous mat as a new vitamin E (VE) delivery system based on silk fibroin (SF)/poly(vinyl alcohol) (PVA)/aloe vera (AV) was successfully prepared by the electrospinning method. Initially, VE-loaded starch nanoparticles were produced and then incorporated into the best beadless SF-PVA-AV nanofibers. The successful loading of VE in starch nanoparticles was proved by Fourier-transform infrared spectroscopy. The scanning electron microscopy and transmission electron microscopy indicated that spherical nanoparticles were successfully embedded within the nanofibers. In vitro release studies demonstrated that the release of VE was controlled by Fickian diffusion and was faster in samples containing more nanoparticles. Fibroblast attachment, proliferation, and collagen secretion were enhanced after adding AV and VE to the SF-PVA nanomatrix. Moreover, the incorporation of VE into the nanocomposite dressing enhanced antioxidant activity, which can have a positive effect on wound healing process by protecting the cells from toxic oxidation products.

Creation and Evaluation of New Porcine Model for Investigation of Treatments of Surgical Site Infection.

Surgical site infection (SSI) is the most common cause of surgical failure, increasing the risks of postoperative mortality and morbidity. Recently, it has been reported that the use of antimicrobial dressings at the incision site help with prevention of SSI. Despite the increased body of research on the development of different types of antimicrobial dressings for this application, to our knowledge, nobody has reported a reliable large animal model to evaluate the efficacy of developed materials in a preclinical SSI model. In this study, we developed a porcine full-thickness incision model to investigate SSI caused by methicillin-resistant Staphylococcus aureus (MRSA), the leading cause of SSI in the United States. Using this model, we then evaluated the efficacy of our newly developed silver releasing nanofibrous dressings for preventing and inhibiting MRSA infection. Our results confirmed the ease and practicality of a new porcine model as an in vivo platform for evaluation of biomaterials for SSI. Using this model, we found that our silver releasing scaffolds significantly reduced bacterial growth in wounds inoculated with MRSA relative to nontreated controls and to wounds treated with the gold standard, silver sulfadiazine, without causing inflammation at the wound site. Findings from this study confirm the potential of our silver-releasing nanofibrous scaffolds for treatment/prevention of SSI, and introduce a new porcine model for in vivo evaluation of additional SSI treatment approaches.

Pectinate nanofiber mat with high absorbency and antibacterial activity: A potential superior wound dressing to alginate and chitosan nanofiber mats

Polysaccharides including pectin, alginate and chitosan are fabricated into dressings of micrometer-scaled architecture (micro- fiber or particle) and widely applied in wound treatments clinically. This work characterized and compared the properties of electrospun nanofibrous dressings of these polysaccharides. We found that although the three polysaccharide nanofiber mats had comparable mechanical strength and vapour permeability, the pectinate nanofiber mat could absorb 1.2 times and 3.6 times more exudates than the alginate and chitosan nanofiber mats, respectively, within less time. Moreover, the pectinate nanofiber mat showed much higher antibacterial activity (73.1%) than the alginate and chitosan nanofiber mats (11.8% and 17.1%, respectively). Further examinations demonstrated that the superior absorbency and antibacterial activity of the pectinate nanofiber mat were associated with the moderate extent of swelling of pectinate nanofibers under hydrated conditions. All these results suggest that the pectinate nanofiber mat might be a superior wound dressing to the alginate and chitosan nanofiber mats.

The Feasibility of a Handheld Electrospinning Device for the Application of Nanofibrous Wound Dressings.

Objectives: The aim of this study was to determine the feasibility of a portable electrospinning device for the application of wound dressings. Approach: Four polymer nanofibers dressings were applied on superficial partial thickness wounds to a porcine model and compared with a traditional paraffin tulle gras dressing. The polymer nanofibrous dressings were applied using a handheld portable electrospinning device activated at a short distance from the wound. The partial thickness donor sites were evaluated on day 2, 7, and 14 when dressings were removed and tissue samples were taken for histological examination. Results: No significant difference was detected between the different electrospun nanofibrous dressings and traditional paraffin tulle gras. Desirable characteristics of the electrospun nanofiber dressing group included nontouch technique, ease of application, adherence and reduction in wound edema and inflammation. There was no delayed wound healing or signs of infection reported in both the electrospun nanofiber and traditional tulle gras dressings. Innovation: Used on partial thickness wounds, polymer electrospun nanofiber dressings provide excellent surface topography and are a nontouch, feasible, and safe method to promote wound healing with the potential to reduce wound infections. Such custom-made nanofibrous dressings have implications for the reduction of pain and trauma, number of dressing changes, scarring, and an added cost benefit. Conclusion: We have demonstrated that this portable handheld electrospinning device can be utilized for different formulations and materials and customized according to the characteristics of the target wound at the various stages of wound healing.

Novel nanofibrous dressings containing rhEGF and Aloe vera for wound healing applications

Nanofibrous membranes produced by electrospinning possess a large surface area-to-volume ratio, which mimics the three-dimensional structure of the extracellular matrix. Thus, nanofibrous dressings are a promising alternative for chronic wound healing, since they can replace the natural ECM until it is repaired. Therefore, in this study we have developed a PLGA nanofibrous membrane that contains recombinant human Epidermal Growth Factor (rhEGF) and Aloe vera (AV) extract. Both of them promote wound healing, as EGF is a wound healing mediator and AV stimulates the proliferation and activity of fibroblast. The obtained membranes were composed of uniform and randomly oriented fibers with an average diameter of 356.03±112.05nm, they presented a porosity of 87.92±11.96% and the amount of rhEGF was 9.76±1.75μg/mg. The in vitro viability assay demonstrated that the membranes containing rhEGF and AV improved fibroblast proliferation, revealing the beneficial effect of the combination. Furthermore, these membranes accelerated significantly wound closure and reepithelisation in an in vivo full thickness wound healing assay carried out in db/db mice. Overall, these findings demonstrated the potential of PLGA nanofibers containing rhEGF and AV for the treatment of chronic wounds.

Electrospinning of natural polymers for advanced wound care: towards responsive and adaptive dressings.

In the last few years, the health-care services have registered worldwide an increased number of patients suffering from chronic wounds and ulcers, which are mainly associated with diabetes, obesity and cancer. The need for regenerating rapidly and effectively the injured skin has stimulated the research of advanced therapies for wound care. This review will discuss how biomimetic architectures produced by electrospinning natural biopolymers fulfil most of the requirements of ideal wound dressings. It will also examine the recent progress in the area of portable electrospinning systems and of multiscale instructive materials that integrate stimuli responsive and sensing elements.

Silk fibroin/gelatin electrospun nanofibrous dressing functionalized with astragaloside IV induces healing and anti-scar effects on burn wound

Functional wound dressing has provided new challenges for researchers who focus on burn to improve skin graft quality, reduce scarring, and develop a pluristratified dermal or epidermal construct of a burn wound. This study aimed to investigate the effect of a silk fibroin/gelatin (SF/GT) electrospun nanofibrous dressing loaded with astragaloside IV (AS) on deep partial-thickness burn wound. AS-loaded SF/GT-blended nanofibrous dressing was prepared by electrospinning nanotechnology. The optimal ratio (25:75) of silk fibroin to gelatin was further optimized by evaluating ATR-FTIR characteristics, mechanical properties, porosity, swelling rate, degradation, and release profile of the AS-loaded SF/GT nanofibrous dressing. In contrast to the blank control, the AS-loaded SF/GT nanofibrous dressing promoted cell adhesion and proliferation with good biocompatibility in vitro (p<0.01). This dressing also accelerated wound healing and inhibited scar formation in vivo by stimulating wound closure (p<0.05), increasing angiogenesis, regulating newly formed types of collagen, and improving collagen organization. These results showed that SF/GT nanofibrous dressing is a promising topical drug delivery system. Furthermore, AS-functionalized SF/GT nanofibrous dressing is an excellent topical therapeutic that could be applied to promote healing and elicit anti-scar effects on partial-thickness burn wound.

Fabrication of bioactive glass-introduced nanofibrous membranes with multifunctions for potential wound dressing

Bioactive glass-introduced gelatin/chitosan nanofibrous dressings were developedviaelectrospinning to endow improved antibacterial activity, adjustable bioactivity and water uptake capacity for enhancing chronic wound healing.