Fibrous Matrix Research Articles

Electrospinning vs. Electro-Assisted Solution Blow Spinning for Fabrication of Fibrous Scaffolds for Tissue Engineering

Biodegradable polymeric fibrous non-woven materials are widely used type of scaffolds for tissue engineering. Their morphology and properties could be controlled by composition and fabrication technology. This work is aimed at development of fibrous scaffolds from a multicomponent polymeric system containing biodegradable synthetic (polylactide, polycaprolactone) and natural (gelatin, chitosan) components using different methods of non-woven mats fabrication: electrospinning and electro-assisted solution blow spinning. The effect of the fabrication technique of the fibrous materials onto their morphology and properties, including the ability to support adhesion and growth of cells, was evaluated. The mats fabricated using electrospinning technology consist of randomly oriented monofilament fibers, while application of solution blow spinning gave a rise to chaotically arranged multifilament fibers. Cytocompatibility of all fabricated fibrous mats was confirmed using in vitro analysis of metabolic activity, proliferative capacity and morphology of NIH 3T3 cell line. Live/Dead assay revealed the formation of the highest number of cell-cell contacts in the case of multifilament sample formed by electro-assisted solution blow spinning technology.

3D-Printed Prolamin Scaffolds for Cell-Based Meat Culture.

Cultivating meat from muscle stem cells in vitro requires 3D edible scaffolds as the supporting matrix. Electrohydrodynamic (EHD) printing is an emerging 3D-printing technology for fabricating ultrafine fibrous scaffolds with high precision microstructures for biomedical applications. However, edible EHD-printed scaffolds remain scarce in cultured meat (CM) production partly due to special requirements with regard to the printability of ink. Here, hordein or secalin is mixed, which are cereal prolamins extracted from barley or rye, with zein to produce pure prolamin-based inks, which exhibit favorable printability similar to common polycaprolactone ink. Zein/hordein and zein/secalin scaffolds with highly ordered tessellated structures are successfully fabricated after optimizing printing conditions. The prolamin scaffolds demonstrated good water stability and in vitro degradability due to the porous fiber surface, which is spontaneously generated by culturing muscle cells for 1week. Moreover, mouse skeletal myoblasts (C2C12) and porcine skeletal muscle satellite cells (PSCs) can adhere and proliferate on the fibrous matrix, and a CM slice is produced by culturing PSCs on prolamin scaffolds with high tissue similarity. The upregulation of myogenic proteins shows that the differentiation process is triggered in the 3D culture, demonstrating the great potential of prolamin scaffolds in CM production.

A Multilayer Nanofibrous Mat for the Topical Chemotherapy of the Positive Margin in Bladder Cancer.

Treatment of positive margins after solid tumor resection remains a significant challenge for clinicians. Owing to unique structural features, electrospun nanofibrous mats are promised to be an implantable antitumor system through the delivery of active agents in a controlled manner. In this study, we utilized sequential electrospinning to fabricate a multilayer mat in which gemcitabine (GEM) and cisplatin (CDDP) were electrospun individually in distinct layers. By designing the structure, the multilayer mat could deliver antitumor agents sustainedly and prolong the release of GEM, which is loaded in the inner layer. In vitro assays show that the multilayer mats effectively inhibit bladder cancer (BC) cells and elevate apoptosis. In animal models of BC, the implantable drug-loaded fibrous mat can effectively treat positive margins and prevent local recurrence. Moreover, the local delivery of GEM and CDDP significantly lowers liver toxicity compared with systemic chemotherapy. In summary, a multilayer nanofibrous mat is developed for the localized and controlled delivery of GEM, dramatically improving the treatment of residual tumors and preventing BC recurrence. Impact statement The designed multilayer nanofibrous mats can achieve two chemotherapeutic drugs (gemcitabine and cisplatin) co-loading and time-programmed sustained release, significantly improving our previous study. The antitumor effect of the drug-loaded mat in vivo and in vitro was sufficiently demonstrated. We expect to bring a new strategy of topical chemotherapy for treating positive surgical margins in bladder cancer.

Bio-Based Electrospun Fibers from Chitosan Schiff Base and Polylactide and Their Cu2+ and Fe3+ Complexes: Preparation and Antibacterial and Anticancer Activities.

The Schiff base derivative (Ch-8Q) of chitosan (Ch) and 8-hydroxyquinoline-2-carboxaldehyde (8QCHO) was prepared and fibrous mats were obtained by the electrospinning of Ch-8Q/polylactide (PLA) blend solutions in trifluoroacetic acid (TFA). Complexes of the mats were prepared by immersing them in a solution of CuCl2 or FeCl3. Electron paramagnetic resonance (EPR) analysis was performed to examine the complexation of Cu2+(Fe3+) in the Ch-8Q/PLA mats complexes. The morphology of the novel materials and their surface chemical composition were studied by scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The performed microbiological screening demonstrated that in contrast to the neat PLA mats, the Ch-8Q-containing mats and their complexes were able to kill all S. aureus bacteria within 3 h of contact. These fibrous materials had efficiency in suppressing the adhesion of pathogenic bacteria S. aureus. In addition, Ch-8Q/PLA mats and their complexes exerted good anticancer efficacy in vitro against human cervical HeLa cells and human breast MCF-7 cells. The Ch-8Q-containing fibrous materials had no cytotoxicity against non-cancer BALB/c 3T3 mouse fibroblast cells. These properties render the prepared materials promising as wound dressings as well as for application in local cancer treatment.

Colorimetric active carboxymethyl chitosan/oxidized sodium alginate-Oxalis triangularis ssp. papilionacea anthocyanins film@gelatin/zein-linalool membrane for milk freshness monitoring and preservation

Colorimetric active double-layer composites of film@membrane were developed via direct electrospinning functional nanofibers on colorimetric film. In the structure, oxidized sodium alginate cross-linked carboxymethyl chitosan (CO) was used as colorimetric film matrix to incorporate the anthocyanins extract from Oxalis triangularis ssp. papilionacea (OTA); while the blend of gelatin/zein (GZ) was used as fibrous matrix for linalool (L) encapsulation. Besides good barrier and water resistance, the outer-layer of CO-OTA showed colorimetric sensitivity towards pH-stimuli with reversible color changes. The inner-layer of GZ-L exhibited good antibacterial activities against Staphylococcus aureus and Escherichia coli. The volatile release of L from fibrous matrix was well controlled and mainly followed Fickian diffusion. Moreover, the antioxidant activity of the composites is source from the released linalool. The high reliability on milk freshness monitoring and double shelf-life extending at 25 °C suggest the potential of CO-OTA@GZ-L in colorimetric active food packaging.

Rotary Jet Spinning (RJS): A Key Process to Produce Biopolymeric Wound Dressings.

Wounds result from different causes (e.g., trauma, surgeries, and diabetic ulcers), requiring even extended periods of intensive care for healing, according to the patient's organism and treatment. Currently, wound dressings generated by polymeric fibers at micro and nanometric scales are promising for healing the injured area. They offer great surface area and porosity, mimicking the fibrous extracellular matrix structure, facilitating cell adhesion, migration, and proliferation, and accelerating the wound healing process. Such properties resulted in countless applications of these materials in biomedical and tissue engineering, also as drug delivery systems for bioactive molecules to help tissue regeneration. The techniques used to engineer these fibers include spinning methods (electro-, rotary jet-), airbrushing, and 3D printing. These techniques have important advantages, such as easy-handle procedure and process parameters variability (type of polymer), but encounter some scalability problems. RJS is described as a simple and low-cost technique resulting in high efficiency and yield for fiber production, also capable of bioactive agents' incorporation to improve the healing potential of RJS wound dressings. This review addresses the use of RJS to produce polymeric fibers, describing the concept, type of configuration, comparison to other spinning techniques, most commonly used polymers, and the relevant parameters that influence the manufacture of the fibers, for the ultimate use in the development of wound dressings.

Synthesis and Fabrication of a Betulin-Containing Polyolefin Electrospun Fibrous Mat for Antibacterial Applications.

Biocompounds play a significant role in the area of renewable polymers in terms of sustainability, as they can be employed or converted into monomers for polymerization in a manner similar to many petroleum-derived monomers. In this work, betulin, a plant-derived triterpene with antibacterial and antiviral properties, was converted to two kinds of α,ω-diene derivatives with different methylene spacer lengths between the olefin and the ester group via an esterification reaction. Polyolefins were subsequently made by acyclic diene metathesis (ADMET) polymerization of betulin-based α,ω-diene. The polymer consists of rigid betulin and flexible unsaturated aliphatic segments, which was confirmed by NMR spectroscopy and gel permeation chromatography (GPC). The influence of different parameters including temperature, catalysts, and catalyst loading on ADMET polymerization was investigated. These polyolefins with high molar mass (up to 20.0 kg/mol) were obtained in an elevated yield (≥95%). Thermal analysis of these (co)polymers showed excellent thermal stability (up to 360 °C) and tunable glass transition temperatures depending on the nature of betulin and alkene segments. To evaluate the antimicrobial potential of betulin-containing polymers, the fabrication of polyolefin fibrous mats (ca. 400 nm diameter) via the electrospinning technique was successfully achieved. Their morphology and hydrophobicity were studied by scanning electron microscopy (SEM) and water contact angle analyses. The fibrous mats possessed broad-spectrum antibacterial property, providing a feasible strategy to design betulin-based polymeric fibers for many applications in the biomedical field.

Pre-strain accommodation enabled multi-dimensionally and hierarchically elastomeric MoSe2/MXene and AC/MXene electrodes for stretchable sodium ion capacitors

Stretchable supercapacitors with simultaneously high energy/power densities and long life can enrich integrated power options for ever-increasing wearable electronics. However, supercapacitors with high electrochemical performances while maintaining high stretchability are still challenging. Herein, we report stretchable sodium ion capacitors (S-SICs) based on multi-dimensionally and hierarchically elastomeric composite electrodes, and stretchable high voltage gel polymer electrolyte (3.0 V). The elastomeric composite electrode is constructed by stretchable 3D electrospun polyurethane (PU) fibrous mat and conductive 1D Ag nanowire network. 2D MoSe2/MXene and 3D AC/MXene as anodic and cathodic materials are embedded in this conductive and stretchable mat. This hierarchical structure enables multi-dimensional conductive connections under tensile condition. The pre-strain treatment on PU fibrous mat further increases the relatively stretching distance before losing conductive connection among hierarchical components. The electrodes exhibit superior sodium ion storage performances (420 mAh g−1 at 5 A g−1), as well as good stretchability and stability (95% after 1000 cycles at 2 A g−1). Based on this, the S-SICs with high operating voltage demonstrate high energy/power densities (max. 5.44 mWh cm−3, 493.55 mW cm−3) and good stretchability. This prototypical exhibition of S-SICs indicates a promising design direction of stretchable supercapacitors with high electrochemical performances and tolerance of stretchability.

Abstract 15136: Matrix Mechanics Regulate Engineered Myocardial Microtissue Organization and Contractility

Introduction: The mechanical function of the myocardium is dictated by cardiomyocytes (CMs) and the surrounding fibrous extracellular matrix (ECM). Due to limitations in existing approaches for engineering myocardial tissue, how CMs sense and respond to mechanical microenvironmental changes remains understudied. Here, we established a method for creating arrays of cardiac microtissues with highly tunable mechanical features by integrating synthetic, fibrous matrices and iPSC-CMs. Through real-time contractility readouts enabled, we explored how biomechanical cues influence engineered cardiac tissue assembly and function. Methods: Arrayed cardiac microtissues were generated by selectively photo-crosslinking electrospun dextran vinyl sulfone fiber matrices onto pairs of microfabricated PDMS cantilevers. Subsequently, iPSC-CMs were patterned onto matrices using a microfabricated seeding mask. Matrix and cantilever stiffnesses were tuned by adjusting photoinitiator concentrations and cantilever geometry, respectively. Results: In tissues contracting against soft cantilevers (0.41 N/m), tissue contractile stress decreased with increasing matrix stiffness (E = 0.68 to 17.3 kPa). We also observed an increase in contractile stress on soft and aligned matrices, compared to non-aligned matrices. However, tissues contracting against stiffer cantilevers (1.2 N/m) exerted similar contractile stresses independent of matrix alignment. This may be explained by the enhanced alignment of myofibrils in non-aligned matrices contracting against stiffer posts. The size of vinculin-rich cell-ECM adhesion decreased on stiff matrices. Vinculin also localized to z-discs forming organized costameres on soft matrices. Tissue response to mavacamten suggests that β-cardiac myosins are required for costamere formation and myofibril maturation. Conclusions: We developed a new microfabrication strategy to create tunable cardiac microtissues and examined how biomechanical cues affect tissue assembly and function. We found that matrix stiffness, matrix alignment, and tissue constraint distinctly affect iPSC-CM function and structure, potentially due to differential influences on costamere formation and myofibrillar assembly.

Abstract 15800: Dissecting Cardiomyocyte-Fibroblast Communication During Homeostasis and Cardiac Fibrosis in a Compartmentalized Biomimetic Tissue Model

Introduction: Cardiac fibroblasts (CFs) maintain cardiac structure and function by synthesizing and remodeling the extracellular matrix (ECM) found throughout the heart. Homeostatic maintenance of the ECM required for healthy tissue function depends on CF communication with cardiomyocytes (CMs). During cardiac fibrosis, signals resulting from tissue injury and dysregulated CF-CM communication promote CF differentiation into α-smooth muscle actin + (αSMA) myofibroblasts (MFs), which deposit excess ECM that mechanically impairs heart function. Given the challenges involved in parsing the dynamic and multifactorial heterocellular interactions underlying tissue homeostasis versus fibrosis, we engineered a compartmentalized, bilayer cardiac tissues where iPSC-derived CMs and CFs can be cultured on either side of a shared fibrous ECM to study CM-CF communication. Methods: Dextran vinyl sulfone (DVS) fibers were electrospun onto arrays of microfabricated PDMS wells. Matrix stiffness and alignment were controlled by modulating the speed of the collecting surface and UV light exposure, respectively. iPSC-CMs and primary human CFs were seeded onto opposing sides of the matrix. Immunostaining for αSMA was conducted to assess CF differentiation to MFs. Results: In CF monocultures on matrices varying in alignment and stiffness, MF differentiation was greatest on stiff (17.3 kPa) aligned matrices with exogenous TGFβ1 compared to soft (0.68 kPa) aligned matrices and both soft/stiff random matrices. We also observed increased nuclear YAP expression on stiff/aligned matrices, indicating altered mechanosensing in response to matrix properties. However, the presence of co-cultured CMs inhibited MF differentiation despite exogenous TGFβ1. MF differentiation was also impaired in CFs cultured on glass below matrix-seeded CMs, implying the role of protective paracrine signaling from CMs to CFs. Conclusions: We developed a microfabricated biomimetic coculture platform to examine CM-CF communication driving tissue homeostasis versus fibrosis. Specifically, we find that fibrous mechanical cues modulate YAP-mediated signaling and αSMA expression. Further, CM-CF paracrine signaling mitigates MF differentiation on aligned fibrous matrices.

Encapsulation of TA in edible nanofibrous mat improves antioxidant efficiency and their modulation of fatty acids profile in flaxseed oil

SummaryEncapsulation of tannic acid (TA) in an edible guar gum (GG) – the nanofibrous delivery system was applied to improve antioxidant efficacy relative to butylated hydroxytoluene (BHT) and non‐encapsulated TA under accelerated oxidation of flaxseed oil (FO). The TA fibrous mat (average fibre diameter of 96 ± 22 nm) significantly improved oxidative stability compared to BHT‐ and non‐encapsulated TA‐treated samples during the oil‐accelerated oxidation test (peroxide value, p‐anisidine, P < 0.05). Principal component analysis (PCA) for eight fatty acids: palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, linoleic acid, linolenic acid and palmitoleic acid, explained 80.0% of the total variation. Linolenic acid, palmitoleic acid and stearic acid were essential to the discrimination of fatty acid changes in the PLS model among all the studied variables. After 30 days of oxidation, TA fibrous‐mat‐treated FO was separated from the control‐, BHT‐ and non‐encapsulated TA‐treated sample, mainly due to the changes in linolenic acid. Our original study provides a novel method to improve the oxidative stability of FO and may support further exploration of the interaction between active nanodelivery systems and fatty acids.

Concentration of Fibroblasts in the Vocal Fold of Elderly

To study the concentration of fibroblasts in the vocal folds of elderly people. The vocal folds of 13 cadavers were removed and divided into two age groups: Control group: n-5, 18-40 years; Elderly group: n-8, ≥75 years). The vocal folds were dissected and prepared for immunohistochemical analysis using the SA100 antibody to fibroblasts. The sites analyzed were maculae flavae and medial (or vibrating) portion of the vocal folds. The AVsoft program was used to count the cells. A higher concentration of fibroblasts was identified in the maculae flavae of the larynx of young adults and in the medial portion of the vocal folds of the elderly. However, these results did not determine statistically significant differences, allowing us to conclude that there was no effect of age on the concentration of fibroblasts in the vocal folds. In the larynx of the elderly, the fibroblast population remains similar to the young adults, both in the maculae flavae and in the body of the vocal folds, possibly being responsible for the constant production of fibrous matrix in the lamina propria. Functional changes in these cells are probably more marked than quantitative ones.

Strength Properties of Cellulosic Fibrous Mats Impregnated with Water Repellents Based on Reclaimed Polystyrene

Cellulosic fibrous mats were impregnated with various water-repellent formulations based on reclaimed polystyrene (5, 10, 15, and 20%), alkyd resin (5%), gum rosin (5%), and paraffin wax (0.5%). The mats were tested for their bursting strength and resistance to bending. They were also subjected to the ring crush test and short-span compression test. By increasing the concentration of total solid ingredients (5, 10, 15, 20, and 25.5%), the retention and grammage of the mats were increased, and all strength properties were improved. All formulations containing 20% reclaimed polystyrene had the highest strength properties. The formulations containing alkyd resin had higher bursting and bending strength than gum rosin. However, the formulations with gum rosin exhibited higher strength than those with alkyd resin in the ring crush test and the short-span compression test. Adding paraffin wax in formulations with 20% reclaimed polystyrene and gum rosin did not affect the strength properties.

Films, Gels and Electrospun Fibers from Serum Albumin Globular Protein for Medical Device Coating, Biomolecule Delivery and Regenerative Engineering.

Albumin is a natural biomaterial that is abundantly available in blood and body fluids. It is clinically used as a plasma expander, thereby increasing the plasma thiol concentration due to its cysteine residues. Albumin is a regulator of intervascular oncotic pressure, serves as an anti-inflammatory modulator, and it has a buffering role due to its histidine imidazole residues. Because of its unique biological and physical properties, albumin has also emerged as a suitable biomaterial for coating implantable devices, for cell and drug delivery, and as a scaffold for tissue engineering and regenerative medicine. As a biomaterial, albumin can be used as surface-modifying film or processed either as cross-linked protein gels or as electrospun fibers. Herein we have discussed how albumin protein can be utilized in regenerative medicine as a hydrogel and as a fibrous mat for a diverse role in successfully delivering drugs, genes, and cells to targeted tissues and organs. The review of prior studies indicated that albumin is a tunable biomaterial from which different types of scaffolds with mechanical properties adjustable for various biomedical applications can be fabricated. Based on the progress made to date, we concluded that albumin-based device coatings, delivery of drugs, genes, and cells are promising strategies in regenerative and personalized medicine.

Surface Modification of PHBV Fibrous Scaffold via Lithium Borohydride Reduction.

In this study, lithium borohydride (LiBH4) reduction was used to modify the surface chemistry of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibers. Although the most common reaction employed in the surface treatment of polyester materials is hydrolysis, it is not suitable for fiber modification of bacterial polyesters, which are highly resistant to this type of reaction. The use of LiBH4 allowed the formation of surface hydroxyl groups under very mild conditions, which was crucial for maintaining the fibers' integrity. The presence of these groups resulted in a noticeable improvement in the surface hydrophilicity of PHBV, as revealed by contact angle measurements. After the treatment with a LiBH4 solution, the electrospun PHBV fibrous mat had a significantly greater number of viable osteoblast-like cells (SaOS-2 cell line) than the untreated mat. Moreover, the results of the cell proliferation measurements correlated well with the observed cell morphology. The most flattened SaOS-2 cells were found on the surface that supported the best cell attachment. Most importantly, the results of our study indicated that the degree of surface modification could be controlled by changing the degradation time and concentration of the borohydride solution. This was of great importance since it allowed optimization of the surface properties to achieve the highest cell-proliferation capacity.

Encapsulation of Lactobacillus rhamnosus GG in edible electrospun mats from calcium and sodium caseinates with pullulan blends

Electrospinning has been proposed as a method to encapsulate and preserve bioactive compounds in nanofibrous mats to ensure their delivery and associated health benefits when consumed directly or added to a food formulation. In previous work, we demonstrated the production of edible fibers to form mats of both calcium (CaCAS) and sodium (NaCAS) caseinate-pullulan (PUL), with the polysaccharide PUL added as a carrier to facilitate molecular entanglement for fiber formation. In this study, we determined the viability of the probiotic bacteria, Lactobacillus rhamnosus GG (LGG), used as a model bacterium, in mats of CaCAS-PUL and NaCAS-PUL. Electrospinning of aqueous solutions at room temperature (21 ± 1°C) of 15% (wt/wt) CaCAS and NaCAS mixed with 15% (wt/wt) PUL, with a 1:1 ratio of CAS:PUL, resulted in fibrous mats with average fiber diameter sizes of 233 ± 20 and 244 ± 21 nm, respectively, as determined by scanning electron microscopy. Addition of LGG in the amounts of 9.3 and 9.0 log10 cfu/mL to the CaCAS-PUL and NaCAS-PUL solutions before electrospinning resulted in average fiber diameter sizes of 212 ± 14 and 286 ± 16 nm, respectively. The LGG was found to be distributed within the CaCAS-PUL and NaCAS-PUL fibers. The addition of LGG increased the shear viscosity and conductivity of the CaCAS-PUL solution, enhancing molecular entanglement and resulting in thinner fibers. For NaCAS, LGG increased the conductivity but reduced shear viscosity. Adjustment of the NaCAS-PUL composition would be needed to optimize conditions for thinner fibers. The numbers of viable LGG recovered from the CaCAS-PUL and NaCAS-PUL nanofibrous mats after electrospinning were 9.5 and 9.6 log10 cfu/g, respectively, proving that the electrospinning conditions used were capable of supporting probiotic encapsulation. These results demonstrate that food-grade electrospun fibrous mats can be used to develop functional foods with delivery of probiotics to improve human or animal health.

Heterogeneous Cu9S5/C nanocomposite fibers with adjustable electromagnetic parameters for efficient electromagnetic absorption

One-dimensional carbon-based materials have emerged as promising electromagnetic wave absorption agents due to their outstanding conductivity, high stability, low weight, and easy availability. Properly optimizing their electromagnetic parameters is expected to further enhance the electromagnetic wave attenuation capacity. In this work, efficient Cu9S5/C nanocomposite fibers are prepared by a combined approach of electrospinning and subsequent carbonization-sulfurization processes. The Cu9S5 nanoparticles with size of ca. 100–200 nm were homogeneously embedded in fibrous carbon matrix with diameter of 300 nm. For electromagnetic wave absorption, the optimized composited nanofibers (Cu9S5/C-3) exhibited an extremely superb reflection loss of −65.4 dB (9.5 GHz, 2.7 mm) at a lower mass fraction (20 wt%). And the effective absorption bandwidth could be up to 4.1 GHz (8.0–12.1 GHz) with a matching thickness of 2.9 mm, covering the whole X-band. Electromagnetic wave attenuation mechanism investigation revealed that the performance enhancement originated from the synergy of various loss pathways, including interfacial polarization, dipole polarization, and conductive loss. The unique hierarchical structure from particle embedding, one-dimensional fiber, to three-dimensional network further amplified the performance advantages of each component. This work is anticipated to provide a feasible strategy to synthesize sulfide/carbon binary composite fibers for efficient electromagnetic wave absorption.

Dual drug delivery system based on layered double hydroxides/carboxymethyl cellulose-poly ethylene oxide bionanocomposite electrospun fibrous mats: Fabrication, characterization, in-vitro and in-vivo studies

The main goal of the present project was to design and develop ibuprofen (IBU) and layered double hydroxides-vancomycin (LDH-VAN) nanohybrid loaded bionanocomposite fibrous mats to increase the wound healing rate. Thus, first, LDH-VAN nanohybrid particles was synthesized by in-situ incorporation of VAN into the Mg-Al-LDH interlayers during the co-precipitation of hydroxides. Then, LDH-VAN/IBU/CMC-PEO bionanocomposite fibrous mats were fabricated by electrospinning technique. Test samples were examined XRD, SEM, TEM, TGA, and FTIR. In vitro drug release test was performed in the phosphate buffer solution (pH = 7.4) to prove the efficiency of the fabricated bionanocomposite fibrous mats as a sustained-release carrier for both VAN and IBU. All the fabricated bionanocomposite fibrous mats did not displayed any significant cytotoxicity on NIH/3 T3 fibroblast cells. The wound area in the rats treated with LDH-VAN/IBU/CMC-PEO bionanocomposite fibrous mats was less than other treatment groups. Based on histological analysis, the LDH-VAN/IBU/CMC-PEO bionanocomposite fibrous mats possess a faster wound healing than other nanofibrous mats. Data obtained from the present project indicated that LDH-VAN/IBU/CMC-PEO bionanocomposite fibrous mats could accelerate the wound healing process.

The Impact of Coating Defects on Water Transport in the Gas Diffusion Layer of PEM Fuel Cells

Present study suggests that the breakthrough pressure of a mixed-non-wetting (MNW) meniscus is highly sensitive to the extent of coating defects. On the other hand, the wetting meniscus breakthrough pressure showed little sensitivity to the geometry of the pore. Hydrophobic coatings such as PTFE are used to improve the water transport behaviour of the gas diffusion layer. Improved performance is typically associated with high breakthrough pressure, as evidenced by experiments. Simulations employing pores consider the influence of the pore geometry, and that of heterogeneous wetting and pinning conditions of the water droplets in contact with the GDL fibrous matrix. This model examines the water percolation behaviour at pore level, the pore being defined as a contact line of an evolving droplet in contact with fibers. In contrast with the pores of a pore-network model, the pore-level model captures the evolution of a liquid-gas interface having both pinned and free contact line segments. The mixed-non-wetting behaviour is caused by the hydrophobic coating which allows parts of the meniscus contact line to deform freely in contact with the fibers, while other parts of the meniscus remain pinned due to coating defects. The MNW meniscus is critical to establishing a high breakthrough pressure and a small characteristic droplet volume. The influence of the coating defects is simulated by MNW menisci having various ratios of pinned-to-free contact line segments.

Chain-End Functionalization of Poly(ε-caprolactone) for Chemical Binding with Gelatin: Binary Electrospun Scaffolds with Improved Physico-Mechanical Characteristics and Cell Adhesive Properties.

Composite biocompatible scaffolds, obtained using the electrospinning (ES) technique, are highly promising for biomedical application thanks to their high surface area, porosity, adjustable fiber diameter, and permeability. However, the combination of synthetic biodegradable (such as poly(ε-caprolactone) PCL) and natural (such as gelatin Gt) polymers is complicated by the problem of low compatibility of the components. Previously, this problem was solved by PCL grafting and/or Gt cross-linking after ES molding. In the present study, composite fibrous scaffolds consisting of PCL and Gt were fabricated by the electrospinning (ES) method using non-functionalized PCL1 or NHS-functionalized PCL2 and hexafluoroisopropanol as a solvent. To provide covalent binding between PCL2 and Gt macromolecules, NHS-functionalized methyl glutarate was synthesized and studied in model reactions with components of spinning solution. It was found that selective formation of amide bonds, which provide complete covalent bonding of Gt in PCL/Gt composite, requires the presence of weak acid. With the use of the optimized ES method, fibrous mats with different PCL/Gt ratios were prepared. The sample morphology (SEM), hydrolytic resistance (FT-IR), cell adhesion and viability (MTT assay), cell penetration (fluorescent microscopy), and mechanical characteristics of the samples were studied. PCL2-based films with a Gt content of 20 wt% have demonstrated the best set of properties.