Development and characterization of collagen-based electrospun scaffolds containing silver sulphadiazine and Aspalathus linearis extract for potential wound healing applications

Bilayer regenerated cellulose/quaternized chitosan-hyaluronic acid/collagen electrospun scaffold for potential wound healing applications

In this study, a bilayer electrospun scaffold has been prepared using regenerated cellulose (RC)/quaternized chitosan (CS) as the primary layer and collagen/hyaluronic acid (HA) as the second layer. An approximate 48 mol% substituted (estimated from 1H NMR) quaternized CS was used in this study. Both layers were crosslinked with EDC/NHS, reflecting an increase in UTS (2.29 MPa for the bilayer scaffold compared to 1.82 MPa for the RC scaffold). Initial cell viability, cell adhesion and proliferation, FDA staining for live cells, and hydroxyproline release rate from cells were evaluated with L929 mouse fibroblast cells. Also, detailed in vitro studies were performed using HADF cells, which include MTT Assay, Live/Dead imaging, DAPI staining, gene expression of PDGF, VEGF-A, and COL1 in RT-PCR, and cell cycle analysis. The collagen/HA-based bilayer scaffold depicted a 9.76-fold increase of VEGF-A compared to a 2.1-fold increase for the RC scaffold, indicating angiogenesis and vascularization potential. In vitro scratch assay was performed to observe the migration of cells in simulated wounds. Antimicrobial, antioxidant, and protease inhibitory activity were further performed, and overall, the primary results highlighted the potential usage of bilayer scaffold in wound healing applications.

State-of-the-Art Review of Advanced Electrospun Nanofiber Composites for Enhanced Wound Healing

Wound healing is a complex biological process with four main phases: hemostasis, inflammation, proliferation, and remodeling. Current treatments such as cotton and gauze may delay the wound healing process which gives a demand for more innovative treatments. Nanofibers are nanoparticles that resemble the extracellular matrix of the skin and have a large specific surface area, high porosity, good mechanical properties, controllable morphology, and size. Nanofibers are generated by electrospinning method that utilizes high electric force. Electrospinning device composed of high voltage power source, syringe that contains polymer solution, needle, and collector to collect nanofibers. Many polymers can be used in nanofiber that can be from natural or from synthetic origin. As such, electrospun nanofibers are potential scaffolds for wound healing applications. This review discusses the advanced electrospun nanofiber morphologies used in wound healing that is prepared by modified electrospinning techniques.

Development of Mucoadhesive Electrospun Scaffolds for Intravaginal Delivery of Lactobacilli spp., a Tenside, and Metronidazole for the Management of Bacterial Vaginosis

Bacterial vaginosis (BV) is an infection of the vagina associated with thriving anaerobes, such as Gardnerella vaginitis and other associated pathogens. These pathogens form a biofilm responsible for the recurrence of infection after antibiotic therapy. The aim of this study was to develop a novel mucoadhesive polyvinyl alcohol and polycaprolactone electrospun nanofibrous scaffolds for vaginal delivery, incorporating metronidazole, a tenside, and Lactobacilli. This approach to drug delivery sought to combine an antibiotic for bacterial clearance, a tenside biofilm disruptor, and a lactic acid producer to restore healthy vaginal flora and prevent the recurrence of bacterial vaginosis. F7 and F8 had the least ductility at 29.25% and 28.39%, respectively, and this could be attributed to the clustering of particles that prevented the mobility of the crazes. F2 had the highest at 93.83% due to the addition of a surfactant that increased the affinity of the components. The scaffolds exhibited mucoadhesion between 31.54 ± 0.83% and 57.86 ± 0.95%, where an increased sodium cocoamphoacetate concentration led to increased mucoadhesion. F6 showed the highest mucoadhesion at 57.86 ± 0.95%, as compared to 42.67 ± 1.22% and 50.89 ± 1.01% for the F8 and F7 scaffolds, respectively. The release of metronidazole via a non-Fickian diffusion-release mechanism indicated both swelling and diffusion. The anomalous transport within the drug-release profile pointed to a drug-discharge mechanism that combined both diffusion and erosion. The viability studies showed a growth of Lactobacilli fermentum in both the polymer blend and the nanofiber formulation that was retained post-storage at 25 °C for 30 days. The developed electrospun scaffolds for the intravaginal delivery of Lactobacilli spp., along with a tenside and metronidazole for the management of bacterial vaginosis, provide a novel tool for the treatment and management of recurrent vaginal infection.

Bioactive and Physico-Chemical Assessment of Innovative Poly(lactic acid)-Based Biocomposites Containing Sage, Coconut Oil, and Modified Nanoclay

The bioactivity of the versatile biodegradable biopolymer poly(lactic acid) (PLA) can be obtained by combining it with natural or synthetic compounds. This paper deals with the preparation of bioactive formulations involving the melt processing of PLA loaded with a medicinal plant (sage) and an edible oil (coconut oil), together with an organomodifed montmorillonite nanoclay, and an assessment of the resulting structural, surface, morphological, mechanical, and biological properties of the biocomposites. By modulating the components, the prepared biocomposites show flexibility, both antioxidant and antimicrobial activity, as well as a high degree of cytocompatibility, being capable to induce the cell adherence and proliferation on their surface. Overall, the obtained results suggest that the developed PLA-based biocomposites could potentially be used as bioactive materials in medical applications.

Development of curcumin-loaded liposomes in lysine–collagen hydrogel for surgical wound healing

Background

A surgical wound is an incision made by a surgeon. Slow surgical wound healing may lead to chronic wounds which may be a potential health problem. The aim of this study is to formulate curcumin-loaded liposomes in lysine–collagen hydrogel for enhancing surgical wound healing. Curcumin-loaded liposomes were prepared using thin-film hydration method. The liposomal formulation was characterized by analysing its size, morphology, encapsulation efficiency, and in vitro release. The hydrogel base was prepared, and then, curcumin-loaded liposomes were infused to give formulation (F1). Curcumin-loaded liposomes were infused into the hydrogel base after which lysine and collagen were incorporated to give (F2), while (F3) comprised lysine and collagen incorporated in hydrogel base. All formulations were characterized by evaluation of the safety, stability, swelling index, pH, rheological properties, and in vivo wound healing assay. Histology and histomorphometry of tissue samples of wound area treated with formulations F1, F2, and F3 and the control, respectively, were examined.

Results

Curcumin-loaded liposomes were 5–10 µm in size, and the values for encapsulation efficiency and flux of the loaded liposomes are 99.934% and 51.229 µg/cm2/h, respectively. Formulations F1, F2, and F3 had a pH of 5.8. F1 had the highest viscosity, while F2 had the highest swelling index indications for efficient sustained release of drug from the formulation. The in vivo wound healing evaluation showed that curcumin-loaded liposomes in lysine–collagen hydrogel had the highest percentage wound contraction at 79.25% by day three post-surgical operation. Histological evaluation reflected a normal physiological structure of the layers of the epidermis and dermis after surgical wound healing in tissue samples from wound areas treated with formulations F1 and F2. The histomorphometrical values show highest percentage of collagen, lowest inflammatory rates, highest presence of microvessels, and re-epithelization rates at wound site in wounds treated with formulation F2 (curcumin-loaded liposomes in lysine–collagen hydrogel).

Conclusion

Curcumin-loaded liposomes in lysine–collagen hydrogel was found to be the most effective of the three formulations in promoting wound healing. Hence, this formulation can serve as a prototype for further development and has great potential as a smart wound dressing for the treatment of surgical wounds.

Development and characterization of mupirocin encapsulated in animal bone-derived hydroxyapatite for management of chronic wounds

Background

Hydroxyapatite is an important biomedical material used in drug delivery owing to its excellent bioactivity and biocompatibility. In this study, hydroxyapatite isolated from bovine and caprine bones was capped and used as a drug carrier to encapsulate mupirocin as an active pharmaceutical product in hydrogel formulations which were utilized in wound healing application using animal model (Wistar Rats).

Results

Characterization of the mupirocin-encapsulated hydroxyapatite using Fourier transform infrared spectroscopy, and X-ray diffractometer revealed the active presence of mupirocin after encapsulation. The in-vitro drug release study revealed that the capped hydroxyapatite obtained from caprine bone loaded with mupirocin gave drug release rate of 84.67% of the drug within 75 min while conventional mupirocin ointment had the lowest at 27.04% within the same time. The capped hydroxyapatite obtained from bovine bone loaded with mupirocin had the highest encapsulation efficiency of 73.67%. However, the animals treated with formulation prepared from capped hydroxyapatite obtained from caprine bone loaded with mupirocin had the highest wound closure area of 377.8 mm2, while conventional mupirocin ointment had 231.5 mm2 in 16 days of treatment. All the formulations with mupirocin except the ointment showed excellent resistance against Klebsiella pneumonia and Staphylococcus aureus of about 40 mm of inhibition zone.

Conclusions

The mupirocin encapsulated in hydroxyapatite extracted from bovine and caprine bones has been demonstrated to be more superior to the conventional ointment in the management of chronic wound conditions.

Biomaterials-Based Regenerative Strategies for Skin Tissue Wound Healing

Skin tissue wound healing proceeds through four major stages, including hematoma formation, inflammation, and neo-tissue formation, and culminates with tissue remodeling. These four steps significantly overlap with each other and are aided by various factors such as cells, cytokines (both anti- and pro-inflammatory), and growth factors that aid in the neo-tissue formation. In all these stages, advanced biomaterials provide several functional advantages, such as removing wound exudates, providing cover, transporting oxygen to the wound site, and preventing infection from microbes. In addition, advanced biomaterials serve as vehicles to carry proteins/drug molecules/growth factors and/or antimicrobial agents to the target wound site. In this review, we report recent advancements in biomaterials-based regenerative strategies that augment the skin tissue wound healing process. In conjunction with other medical sciences, designing nanoengineered biomaterials is gaining significant attention for providing numerous functionalities to trigger wound repair. In this regard, we highlight the advent of nanomaterial-based constructs for wound healing, especially those that are being evaluated in clinical settings. Herein, we also emphasize the competence and versatility of the three-dimensional (3D) bioprinting technique for advanced wound management. Finally, we discuss the challenges and clinical perspective of various biomaterial-based wound dressings, along with prospective future directions. With regenerative strategies that utilize a cocktail of cell sources, antimicrobial agents, drugs, and/or growth factors, it is expected that significant patient-specific strategies will be developed in the near future, resulting in complete wound healing with no scar tissue formation.

Poly(lactic acid)-Based Electrospun Fibrous Structures for Biomedical Applications

Poly(lactic acid)(PLA) is an aliphatic polyester that can be derived from natural and renewable resources. Owing to favorable features, such as biocompatibility, biodegradability, good thermal and mechanical performance, and processability, PLA has been considered as one of the most promising biopolymers for biomedical applications. Particularly, electrospun PLA nanofibers with distinguishing characteristics, such as similarity to the extracellular matrix, large specific surface area and high porosity with small pore size and tunable mechanical properties for diverse applications, have recently given rise to advanced spillovers in the medical area. A variety of PLA-based nanofibrous structures have been explored for biomedical purposes, such as wound dressing, drug delivery systems, and tissue engineering scaffolds. This review highlights the recent advances in electrospinning of PLA-based structures for biomedical applications. It also gives a comprehensive discussion about the promising approaches suggested for optimizing the electrospun PLA nanofibrous structures towards the design of specific medical devices with appropriate physical, mechanical and biological functions.

Electrospun Fibers Loaded with Natural Bioactive Compounds as a Biomedical System for Skin Burn Treatment. A Review

Burns are a major threat to public health and the economy due to their costly and laborious treatment and high susceptibility to infection. Efforts have been made recently to investigate natural bioactive compounds with potential use in wound healing. The importance lies in the capacities that these compounds could possess both in infection control by common and resistant microorganisms, as well as in the regeneration of the affected tissues, having in both cases low adverse effects. However, some bioactive molecules are chemically unstable, poorly soluble, and susceptible to oxidative degradation or have low bioavailability. Therefore, developing new technologies for an efficient treatment of wound healing poses a real challenge. In this context, electrospun nanofibers have gained increasing research interest because bioactive molecules can be easily loaded within the nanofiber, resulting in optimal burst control and enhanced drug stability. Additionally, the nanofibers can mimic the extracellular collagen matrix, providing a suitable highly porous structural support for growing cells that facilitate and accelerate skin burns healing. This review gives an overview of the current state of electrospun fibers loaded with natural bioactive compounds as a biomedical system for skin burn treatment.

AK, Ramakrishna S, Amirul AAA. Surface Characterization and Physiochemical Evaluation of P(3HB-co-4HB)-Collagen Peptide Scaffolds with Silver Sulfadiazine as Antimicrobial Agent for Potential Infection-Resistance Biomaterial

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] is a bacterial derived biopolymer widely known for its unique physical and mechanical properties to be used in biomedical application. In this study, antimicrobial agent silver sulfadiazine (SSD) coat/collagen peptide coat-P(3HB-co-4HB) (SCCC) and SSD blend/collagen peptide coat-P(3HB-co-4HB) scaffolds (SBCC) were fabricated using a green salt leaching technique combined with freeze-drying. This was then followed by the incorporation of collagen peptides at various concentrations (2.5-12.5 wt.%) to P(3HB-co-4HB) using collagen-coating. As a result, two types of P(3HB-co-4HB) scaffolds were fabricated, including SCCC and SBCC scaffolds. The increasing concentrations of collagen peptides from 2.5 wt.% to 12.5 wt.% exhibited a decline in their porosity. The wettability and hydrophilicity increased as the concentration of collagen peptides in the scaffolds increased. In terms of the cytotoxic results, MTS assay demonstrated the L929 fibroblast scaffolds adhered well to the fabricated scaffolds. The 10 wt.% collagen peptides coated SCCC and SBCC scaffolds displayed highest cell proliferation rate. The antimicrobial analysis of the fabricated scaffolds exhibited 100% inhibition towards various pathogenic microorganisms. However, the SCCC scaffold exhibited 100% inhibition between 12 and 24 h, but the SBCC scaffolds with SSD impregnated in the scaffold had controlled release of the antimicrobial agent. Thus, this study will elucidate the surface interface-cell interactions of the SSD-P(3HB-co-4HB)-collagen peptide scaffolds and controlled release of SSD, antimicrobial agent.

Bio-Based Electrospun Fibers for Wound Healing

Being designated to protect other tissues, skin is the first and largest human body organ to be injured and for this reason, it is accredited with a high capacity for self-repairing. However, in the case of profound lesions or large surface loss, the natural wound healing process may be ineffective or insufficient, leading to detrimental and painful conditions that require repair adjuvants and tissue substitutes. In addition to the conventional wound care options, biodegradable polymers, both synthetic and biologic origin, are gaining increased importance for their high biocompatibility, biodegradation, and bioactive properties, such as antimicrobial, immunomodulatory, cell proliferative, and angiogenic. To create a microenvironment suitable for the healing process, a key property is the ability of a polymer to be spun into submicrometric fibers (e.g., via electrospinning), since they mimic the fibrous extracellular matrix and can support neo- tissue growth. A number of biodegradable polymers used in the biomedical sector comply with the definition of bio-based polymers (known also as biopolymers), which are recently being used in other industrial sectors for reducing the material and energy impact on the environment, as they are derived from renewable biological resources. In this review, after a description of the fundamental concepts of wound healing, with emphasis on advanced wound dressings, the recent developments of bio-based natural and synthetic electrospun structures for efficient wound healing applications are highlighted and discussed. This review aims to improve awareness on the use of bio-based polymers in medical devices.

Polylactic acid-based electrospun fiber and hyaluronic acid-valsartan hydrogel scaffold for chronic wound healing

Background

In this study, the chronic wound healing ability of PLA-based electrospun nanofibers loaded with hyaluronic acid, valsartan, and ascorbic acid is explored. PLA-based scaffolds were fabricated by electrospinning, followed by loading the scaffolds with different concentrations of hyaluronic acid, valsartan, and ascorbic acid hydrogels. The produced formulations were characterized by scanning electron microscopy imaging (SEM), tensile strength testing, Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). An in vitro drug release study was conducted to monitor the release of valsartan from the different formulations. This was followed by exploring the wound healing effects of the scaffolds in alloxan-induced diabetic rats and comparing the wound healing effects with positive and negative controls.

Results

The average diameter of the fibers was in the range of 300 to 490 nm with high porosity in the range of 63.90 to 79.44%, offering a large surface area-to-volume ratio, enhanced drug solubility, oxygen permeability, and fluid uptake. The presence of valsartan significantly impacted on the re-epithelization rate. Percentage re-epithelization rate was 31.2% ± 1.77% in the absence of treatment. Histologic section of tissue showed skin with underlying loose fibro-collagenous stroma (dermis) containing sebaceous glands and hair follicles for animals treated with VA, VB, VC, and VD. All the scaffolds reduced the number of inflammatory cell infiltrates at the wound site compared to the no treatment and conventionally treated groups. Conventional antibiotic treatment and VD (electrospun biomimetic scaffolds containing ascorbic acid) had % re-epithelization rates of 59.45% ± 1.69% and 62.01% ± 1.68% which were significantly lower than the PLA/HA-valsartan hydrogel scaffolds with VB having the highest % re-epithelization rate of 85.5% ± 1.7% (Figure 4B & 5C).

Conclusion

This study explored the use of biomimetic polylactic acid-based electrospun fiber and HA-valsartan hydrogel scaffold incorporating topical angiotensin receptor blockers to successfully accelerate wound healing. The novel PLA-based electrospun fibers loaded with hyaluronic acid-valsartan hydrogels were stable and possessed proven diabetic wound healing property. This was as a result of the known biomimetic effect of the fibers and increased re-epithelization facilitated by the hydrogels containing valsartan.

Graphical abstract

Development of electrospun keratin/coenzyme Q10/poly vinyl alcohol nanofibrous scaffold containing mupirocin as potential dressing for infected wounds

Background

Nanostructured wound dressings produced by electrospinning biocompatible polymers possess great potential because they resemble the natural extracellular matrix and support cell adhesion, proliferation, and differentiation. This study seeks to fabricate mupirocin, keratin, and coenzyme Q10 (Co Q10)-loaded PVA electrospun scaffolds intended for wound healing application and to characterize their morphology, physical properties, antibacterial activity, and biocompatibility. Polyvinyl alcohol (PVA) (10% w/v), various concentrations of keratin/Co Q10 fibrous scaffolds (electrospun at a voltage of 50 kV, flow rate of 4 mL/h), and 2% mupirocin was designed and fabricated to activate keratinocytes in the wound bed, stimulate cell proliferation, and increase antimicrobial penetration.

Results

The diameters of the scaffolds were observed to be in the nanoparticulate range 2.11 ± 0.20 to 3.27 ± 0.10 nm. By 30 min, all the scaffolds had more than 50% of the cumulative concentration of mupirocin released with 51.06 ± 2.104% to 74.66 ± 1.72% of mupirocin released. At 1 h, 80% of the mupirocin in the scaffold was seen to have diffused out of the scaffold. Release of mupirocin was modulated; an initial burst release was followed by sustained release over 2 h. Electrospun keratin/Co Q10/PVA scaffold containing mupirocin showed excellent antimicrobial activity against all the clinical isolates of 2586, Staphylococcus aureus 2590, 2583, 2587, 2555. All the electrospun scaffolds showed higher cell viability values than the control at 48 and 72 h, with the optimized CoQ10 scaffold concentration being 0.05% w/w.

Conclusion

Electrospun nanofibers combining the biocompatibility potential of PVA with the bioactive nature of keratin (0.01% w/w) and CoQ10 (0.5% w/w) and the antibacterial property of mupirocin as a new potential for proper wound care was successfully developed. The cell line studies on this electrospun scaffold (PKCM 3) showed their ability to support the growth of keratinocytes hence the potential of developed scaffolds as a wound dressing. In vivo studies to further investigate the applications of the electrospun keratin/Co Q10/PVA nanofibrous scaffold as a wound dressing is however required.