Mean Fibre Diameter Research Articles

Simultaneous loading of clarithromycin and zinc oxide into the chitosan/gelatin/polyurethane core–shell nanofibers for wound dressing

Clarithromycin as a macrolide antibiotic and zinc oxide (ZnO) nanoparticles with antibacterial and anti-inflammatory properties was incorporated into the chitosan/gelatin/polyurethane (PU) core–shell nanofibers prepared by the coaxial electrospinning method. The morphology and structure of nanofibers were characterized using SEM, FTIR, water contact angle, degradation rate, and swelling tests. The mean fiber diameters of the chitosan/gelatin/PU (CGP), CGP containing 1000 μM clarithromycin, CGP containing 2000 μM clarithromycin, CGP containing 0.5% ZnO, CGP containing 1 wt% ZnO, CGP containing 1000 μM clarithromycin, and 0.5 wt% ZnO and CGP containing 2000 μM clarithromycin, and 1 wt% ZnO were 210 ± 110 nm, 235 ± 100 nm, 250 ± 120 nm, 300 ± 120 nm, 360 ± 130 nm, 410 ± 130 nm, and 460 ± 140 nm, respectively. The gradual faster release of ZnO nanoparticles from core–shell nanofibers was obtained within 24 h; whereas, the sustained release of clarithromycin was achieved during 120 h. Loading of clarithromycin and ZnO nanoparticles into the nanofibers resulted in 100% bactericidal activity of core–shell nanofibers against both Escherichia coli and Staphylococcus aureus. The cell viability results indicated that loading of 0.5 wt% ZnO nanoparticles and 2000 μM clarithromycin was suitable for the development of the synthesized core–shell nanofibers as a potential wound dressing.

Determining the Correct Resection Level in Patients with Hirschsprung Disease Using Contrast Enema and Full Thickness Biopsies: Can the Diagnostic Accuracy be Improved by Examining Submucosal Nerve Fiber Thickness?

BackgroundIntraoperative resection level in patients with Hirschsprung disease (HD) is determined by contrast enema, surgeon's intraoperative judgement and full thickness biopsy (FTB) identifying ganglia. This study aims to evaluate diagnostic accuracy of contrast enema and FTB in determination of resection level and whether this can be improved by measuring submucosal nerve fiber diameter. MethodsWe retrospectively analyzed contrast enema and intraoperative FTBs obtained in our center, determining diagnostic accuracy for level of resection. Gold standard was pathological examination of resection specimen. Secondly, we matched transition zone pull-through (TZPT) patients with non-TZPT patients, based on age and length of resected bowel, to blindly compare nerve fibers diameters between two groups using group comparison. ResultsFrom 2000–2021, 209 patients underwent HD surgery of whom 180 patients (138 males; median age at surgery: 13 weeks) with 18 TZPTs (10%) were included. Positive predictive value of contrast enema was 65.1%. No caliber change was found in patients with total colon aganglionosis (TCA). Negative predictive value of surgeon's intraoperative judgement and FTB in determining resection level was 79.0% and 90.0% (91.2% single-stage, 84.4% two-stage surgery) respectively. Mean nerve fiber diameter in TZPT was 25.01 µm (SD= 5.63) and in non-TZPT 24.35 µm (SD= 6.75) (p = 0.813). ConclusionDetermination of resection level with combination of contrast enema, surgeon's intraoperative judgement and FTB results in sufficient diagnostic accuracy in patients with HD. If no caliber change is seen with contrast enema, TCA should be considered. Resection level or transition zone cannot be determined by assessment of submucosal nerve fiber diameter in FTB. Type of Studyclinical research paper.

Electrospun Chitosan-Polyvinyl Alcohol Nanofiber Dressings Loaded with Bioactive Ursolic Acid Promoting Diabetic Wound Healing.

The design and development of novel dressing materials are urgently required for the treatment of chronic wounds caused by diabetic ulcers in clinics. In this study, ursolic acid (UA) extracted from Chinese herbal plants was encapsulated into electrospun nanofibers made from a blend of chitosan (CS) and polyvinyl alcohol (PVA) to generate innovative CS-PVA-UA dressings for diabetic wound treatment. The as-prepared CS-PVA-UA nanofiber mats exhibited randomly aligned fiber morphology with the mean fiber diameters in the range of 100–200 nm, possessing great morphological resemblance to the collagen fibrils which exist in the native skin extracellular matrix (ECM). In addition, the CS-PVA-UA nanofiber mats were found to possess good surface hydrophilicity and wettability, and sustained UA release behavior. The in vitro biological tests showed that the high concentration of UA could lead to slight cytotoxicity. It was also found that the CS-PVA-UA nanofiber dressings could significantly reduce the M1 phenotypic transition of macrophages that was even stimulated by lipopolysaccharide (LPS) and could effectively restore the M2 polarization of macrophages to shorten the inflammatory period. Moreover, the appropriate introduction of UA into CS-PVA nanofibers decreased the release levels of TNF-α and IL-6 inflammatory factors, and suppressed oxidative stress responses by reducing the generation of reactive oxygen species (ROS) as well. The results from mouse hepatic hemorrhage displayed that CS-PVA-UA nanofiber dressing possessed excellent hemostatic performance. The in vivo animal experiments displayed that the CS-PVA-UA nanofiber dressing could improve the closure rate, and also promote the revascularization and re-epithelization, as well as the deposition and remodeling of collagen matrix and the regeneration of hair follicles for diabetic wounds. Specifically, the mean contraction rate of diabetic wounds using CS-PVA-UA nanofiber dressing could reach 99.8% after 18 days of treatment. In summary, our present study offers a promising nanofibrous dressing candidate with multiple biological functions, including anti-inflammation, antioxidation, pro-angiogenesis, and hemostasis functions, for the treatment of hard-to-heal diabetic wounds.

Design of a nanofibrous guided tissue regeneration carrier as a potential drug delivery system for tetracycline hydrochloride in the management of periodontitis

To accelerate the recovery process in the treatment of periodontitis, a guided tissue regeneration (GTR) nanofibrous membrane containing the antibacterial agent, tetracycline hydrochloride (TCH), was prepared and evaluated for its in vivo performance as a drug carrier in a rabbit model. Polycaprolactone (PCL) solutions containing tetracycline were electrospun to obtain nanofibers and characterized. The surface morphology was investigated and Fourier-transform infrared spectroscopy (FTIR) was performed to detect any potential interactions that may have led to a major alteration of the pharmacologically active moiety. The release behavior was investigated both in vitro and in vivo. The in vitro cytotoxicity was performed to determine the non-toxic nature of the formulation. The antibacterial efficacy was examined against common periodontal pathogens. The formulations possessed suitable strength to preserve their integrity during administration with enough flexibility. A uniform morphology with a mean fiber diameter of 261–324 nm was achieved due to the high potential of the electrospinning process. The antibacterial efficacy and the FTIR confirmed the fact that no major interactions occurred between the drug and polymer. Appropriate cell viability of more than 80% was achieved with no sign of irritation after the implantation of the membranes in a rabbit model. Both in vitro and in vivo studies demonstrated an extended release of the drug for more than 6 days. Suitable biocompatibility in rat and rabbit models was observed. The obtained result suggests that TCH-loaded GTR membranes can be suitable for intrapacket delivery during periodontitis to reduce the frequency of administration and to accelerate the recovery process.

Sequence Variation in Caprine KRTAP6-2 Affects Cashmere Fiber Diameter.

Simple SummaryKeratin-associated proteins (KAPs) are a structural component of wool fibers. Despite the gene encoding the high-glycine/tyrosine KAP6-2 (called KRTAP6-2) having been described in sheep, it has not been identified goats. This study describes the identification of caprine KRTAP6-2, reports variation in the gene, and describes its association with cashmere fiber diameter in Longdong cashmere goats.Keratin-associated proteins (KAPs) are a structural component of cashmere fibers and in part determine fiber attributes. The gene encoding the high-glycine/tyrosine KAP6-2 (called KRTAP6-2) has been described in sheep, but it has not been identified goats. In this study, a 252-bp open reading frame with similarity to ovine KRTAP6-2 was found on goat chromosome 1, with its upstream and downstream flanking sequences are closely related with ovine KRTAP6-2 but are clearly distinct from other ovine KRTAP6-n sequences. Polymerase chain reaction amplification followed by single strand conformation polymorphism analysis of this region revealed five distinct banding patterns representing five different sequences (A to E) in 230 Longdong cashmere goats. Eleven diallelic single nucleotide polymorphisms (SNPs), a three-nucleotide sequence variation, and a 12-bp insertion/deletion were found among these five sequences, with most SNPs being either outside the coding region or synonymous. The presence of variant D was found to be associated with decreased mean fiber diameter (MFD; present: 13.26 ± 0.07 µm; absent: 13.55 ± 0.04 µm; p < 0.001), suggesting that variation in KRTAP6-2 may affect fiber diameter and have value as a molecular marker for improving the cashmere fiber diameter trait.

Relación entre el diámetro de fibra, peso y precio del mercado, en vellones del ovino Junín

The objective of this study was to evaluate the relationship between the mean fiber diameter (MDF), its weight and the sale value, according to the classification categories of wool by the English-Peruvian method, such as the classification of: B, A, AA, AAA and AAAA; For this, we proceeded to obtain 25 samples of fleeces of the same number of sheep with 2 years of age, of the "Junín" breed, once the wicks were obtained, we proceeded with washing, after each wick five sub-samples were separated to measure the MDF, weight and then set the price with the help of Pro Lana as of October 13, 2021. The results indicate a high correlation between the MDF and its weight at a level of 0.01 with 0.756** and with a linear regression of 57.40%; In the same way, a high negative correlation was obtained between the MDF and its market price at a level of 0.01 with -0.985** with a linear regression of 97.10%. Concluding that the finest wool has a lower weightwith a higher price and thicker wool has a higher weight with a lower price.

Enhancement of PCL/PLA Electrospun Nanocomposite Fibers Comprising Silver Nanoparticles Encapsulated with Thymus Vulgaris L. Molecules for Antibacterial and Anticancer Activities.

Silver nanoparticles (AgNPs) have been recognized for their outstanding antibacterial activities, which are required for antibacterial coating materials in therapeutic applications. A bacterial-resistant electrospun nanofibrous mat made of polycaprolactone (PCL) in combination with polylactide acid (PLA) containing silver nanoparticles encapsulated with Thymus vulgaris L. (thyme) extract (eAgNPs) was fabricated in order to assess the potential of applicability in biomedical applications such as cancer treatment, wound healing, or surgical sutures. In the current study, PCL and PLA used as the basis polymers were blended with biosynthesized eAgNPs, pure AgNPs, and thyme extract (TE) to observe the effects of additives in terms of antibacterial and anticancer activity and morphologic, thermal, mechanical, biocompatibility, and biodegradability properties. The biological characteristics of fabricated electrospun nanofibrous mats were evaluated in vitro. Physicochemical characteristics of the nanofibrous mats were examined by UV-vis spectrophotometry, scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), mechanical tensile testing, X-ray diffraction (XRD), thermogravimetric examination (TGA), and water contact angles (WCAs). The results showed that a biodegradable nanofiber scaffold with a mean fiber diameter of 280 nm is morphologically homogeneous and highly hydrophobic, has higher tensile strength than PCL/PLA nanocomposite fiber, and is resistant to Escherichia coli and Staphylococcus aureus. The cytotoxic and anticancer properties of nanomaterials were defined using L929 and SK-MEL-30 cells. The developed material inhibited cell proliferation and led to apoptosis of cell lines. It can be suggested that the use of Thymus vulgaris L. extract-encapsulated silver nanoparticle-doped PCL/PLA nanofibers produced by the electrospinning method has the potential for cancer therapy in skin tumor cell lines.

The adsorptive behaviour of electrospun hydrophobic polymers for optimized uptake of estrogenic sex hormones from aqueous media: kinetics, thermodynamics, and reusability study

AbstractBackgroundEstrogenic hormones as micropollutants in water systems cause severe adverse effects on human health and marine life, leading to fatal diseases, such as breast, ovarian, and prostate cancer. Electrospun polymers have proven high stability and impressive performance in adsorption removal. In this study, electrospun polysulfone (PSU), polyvinylidene fluoride, and polylactic acid were prepared and characterized using scanning electron microscope (SEM), fourier‐transform intrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Brunauer Emmett Teller (BET), surface area measurement X‐Ray diffraction (XRD), and porometry.ResultsNanofibers possess a mean fiber diameter of 149–183 nm and a specific surface area of 1.6–6.3 m2/g. The adsorption efficiency of the simultaneous removal of estrone (E1), 17β‐estradiol (E2), estriol (E3), and 17α‐ethinylestradiol (EE2) in a mixed concentration was investigated using high performace liquid chromatography (HPLC). The results indicate that spun PSU fibers exhibited the highest removal of all four estrogens, with a maximum removal efficiency of 71.2%, 65.9%, 56.9%, and 36.1% and adsorption capacity of 0.508, 0.703, 0.550, and 0.354 mg/g for E1, EE2, E2, and E3, respectively. Additionally, the adsorption was optimised by varying parameters, such as concentration of adsorbate, pH, adsorbent dosage, and temperature, to statistically analyse one‐way variance using ANOVA. The pseudo‐second‐order is best fitted for E1, EE2, and E2, while the pseudo‐first‐order is best for E3. The Langmuir–Freundlich isothermal model was most suitable for evaluation, and the thermodynamics depicted the adsorption to be exothermic and spontaneous.ConclusionThe results indicate that spun PSU can be an efficient adsorbent in the simultaneous elimination of estrogens from wastewater and it exhibits a high regeneration performance of over 60% after six adsorption–desorption cycles. © 2022 Society of Chemical Industry (SCI).

The structural and figure of merit photodetector of PVP-doped with lanthanum

This study describes the fabrication and characterization of PVP and PVP/La thin films from a mixture of high molecular weight polyvinylpyrrolidone (PVP) and (1, 2, and 3)% lanthanum chloride using an electrospinning process on glass and silicon. It includes an N- type (Si) (111) substrate at room temperature. Field Emission Scanning Electron Microscopy (FESEM) analysis reveals fibers with an average diameter in the range of 125-250 nm. The mean fiber diameter decreases with increasing concentration (La). The optical energy gap was determined from the analysis of the transmission spectrum in the UV-visible region. The optical gap (Eg) gradually decreases from 4 eV to 3.64 eV for undoped PVP films due to the increase in La ion content at 3%, which determines the feasibility of using these obtained fibers in the manufacturing process. PVP/La nanofibers as detectors.

Ultrafine nanofiber-based high efficiency air filter from waste cigarette butts

Air and water pollution caused by particulate natters (PM) and waste cigarette butts (WCBs) have wreaked havoc across the globe in last several years, where the latter is subtle in nature. This work aims to tackle both the concerns by recycling WCB into air filter, a value-added product, to remove PMs from air. The air filters consist of ultrafine nanofibers extruded from WCB solution in acetone using supersonic solution blowing (SSB). The ultrafine nanofiber layer, sandwiched between two spunbond polyester membranes, demonstrated remarkable particle filtration efficiency (PFE) of 99.99% at PM2 and 99.7% at PM0.1 when tested at face velocity of 0.96 m/s (i.e., 90 L per minute). The ultrafine nanofiber membrane demonstrated unique architectural feature with 94% volumetric porosity and mean fiber diameter of 92.4 ± 1.2 nm. The structural characterization confirmed its identity as cellulose acetate (CA), free of nicotine and various heavy metals which WCBs generally have. The ultrafine fiber diameter and highly porous structure allowed the 3-ply arrangement to operate at high efficiency with a pressure drop (ΔP) of 50.4 Pa at 0.96 m/s, compared to 41.8 Pa of 2-ply spunbond layers, and PFE of 69.2% at PM2. A laboratory-scale multi-layer prototype filter was developed to mimic a commercial HEPA filter which demonstrated a PFE >99.99% at face velocity of 2.12 m/s and PM0.1. The membrane containing ultrafine nanofibers demonstrated enhanced hydrophobicity (contact angle- 132.8°), which could repel water drops of mean size 256 ± 92 μm when impacted at a velocity of 10 m/s, mimicking a sneezing pattern.

Parameter Screening and Optimization for a Polycaprolactone-Based GTR/GBR Membrane Using Taguchi Design.

Our objective was to determine and optimize the significant parameters affecting mechanical properties and mean fiber diameter (MFD) of a novel GTR/GBR membrane composed of polycaprolactone (PCL) and chicken eggshell membrane (ESM). For this, we prepared electrospun membrane specimens (n = 16) with varying concentrations of PCL, ESM, nano-hydroxyapatite (HAp), and altered electrospinning parameters as generated by DOE++ software. After the determination of MFD and mechanical properties for all specimens, Taguchi orthogonal array L8 design was used to screen significant factors affecting the MFD and mechanical properties. PCL wt%, ESM wt%, HAp wt%, applied voltage (AV), flow rate (FR), and spinneret-collector distance (SCD) were the independent variables investigated. The response variables analyzed were MFD, tensile strength (TS), and elastic modulus. ANOVA outlined ESM wt%, HAp wt%, AV, FR, SCD, and an interactive effect between PCL wt% and AV to be the significant factors affecting modulus values of an electrospun PCL/ESM membrane (p < 0.05). Furthermore, concentrations of PCL and ESM were the significant factors affecting MFD (p < 0.05) and there were no significant factors affecting the TS values. Optimization using DOE++ software predicted that the maximal TS of 3.125 MPa, modulus of 278.168 MPa, and MFD of 882.75 nm could be achieved.

Microstructure and particle filtration behavior of multimodal fibrous filter media made of fibres of different sizes for engine intake air filtration

This paper reports a set of theoretical expressions for describing the microstructure of multimodal fibrous filter media comprising fibres of different cross-sectional sizes along with the application of such expressions to predict the filtration performance of clean and clogging media for engine intake air filtration. It is found that the overall filtration efficiency corresponds very well with the classical theory of air filtration after suitably modifying the single fibre efficiency and mean fibre diameter. The square of mean fibre diameter is found to be a weighted harmonic mean of the square of fibre diameter of individual component. The single fibre efficiency of multimodal filter media, when expressed as a summation of single fibre efficiencies of individual component of fibres weighted by the corresponding surface area fraction, correlates very well with the experimental results. The evolution of pressure drop is explained satisfactorily based on Berman’s approach after suitably modifying the Davies equation.

Electrospun halloysite nanotube loaded polyhydroxybutyrate-starch fibers for cartilage tissue engineering

Articular cartilage is a connective load-bearing tissue with a low rate of regeneration due to slow metabolism. Fabricating tissue-like structure modified based on natural features can improve healing process. Fibrous scaffolds based on the composition of hydrophobic polyhydroxybutyrate (PHB) and hydrophilic starch reinforced using halloysite nanotubes (HNTs) with appropriate physico-chemical and biological properties was produced via electrospinning technique for long-term applications like cartilage regeneration. Textural properties were analyzed through SEM imaging that showed incorporating HNTs up to 2 wt% decreased mean fiber diameter to 158 ± 48 nm with larger pore size and appropriate porosity percentage. Moreover, the tensile strength was improved up to 4.21 ± 0.31 MPa after HNTs incorporation support chondrocyte cell growth. Furthermore, incorporating HNTs induced surface hydrophilicity and in vitro degradation. The biological assays both MTT assay and cell attachment of chondrocyte cells on 2 wt% HNTs incorporated into PHB-starch fibers indicated that HNTs incorporation can support cell growth and attachment without any toxicity for biomedical applications. To conclude, the obtained results demonstrated PHB-starch/HNTs fibrous scaffold could be potential for further experimental studies for tissue engineering applications like cartilage.

Surpassing Cyphochilus scales in optical scattering strength by well-controlled electrospun nanostructures

Scales of Cyphochilus white beetles present one of the strongest optical scattering materials in nature. However, the intricate optical fibrillar network nanostructure inside the scales has been difficult to mimic. Here, characteristic structural parameters inside Cyphochilus scales – mean fiber diameter, diameter distribution, filling fraction, and structural anisotropy – are replicated in synthetic nanofibrous materials to functionally mimic the biological material. To fabricate the synthetic nanostructure, electrospinning is chosen because this conventional technique is amenable to nanomanufacturing. The optimized parameters in electrospun structures are found to be only slightly different from those in Cyphochilus scales. At the optimum, electrospun structures exhibit even stronger optical scattering than Cyphochilus scales. An electrospun film with the similar characteristic structural parameters as those in Cyphochilus scales gives two resonance peaks in visible reflectance spectrum in the limit of a uniform fiber diameter, giving a purple structural color. As the distribution of diameter increases appreciably to experimentally achievable degrees, the resonance peaks broaden and the reflectance spectrum becomes relatively flat, resulting in disappearance of the structural color. These results support that controllable fibrous nanostructures that exceed the exceptionally strong broadband optical scattering found among living organisms can be volume-produced.

Promoting keratocyte stem like cell proliferation and differentiation by aligned polycaprolactone-silk fibroin fibers containing Aloe vera.

There is a long history behind applying biological macromolecules like Aloe vera (AV) in regenerative medicine; endowed with anti-inflammatory and antimicrobial activities besides improving immune activity, AV has always been of particular interest to regenerate/reconstruct injuries and burns. In the present study, aligned electrospun polycaprolactone (PCL)-silk fibroin (SF) fibers containing different percentages of AV (0, 2.5, 5, and 7.5%wt) were fabricated for stromal regeneration. The results illustrated that a uniform bead-free structure was obtained, and the AV incorporation decreased the mean fiber diameter from 552 down to 182nm and led to more alignment in the fibers. The Young's modulus raised from 4.96 to 5.26MPa by higher amount of AV up to 5%wt. It is noteworthy that both the fiber alignment and AV affected the scaffolds' transparency and water uptake to increase. The human stromal keratocyte cells (hSKC)s culture revealed that the addition of AV and morphological properties of scaffolds encouraged cell adhesion and proliferation. The mRNA expression level for keratocan and ALDH3A1 and immunocytochemistry F-actin revealed the positive effect of AV on hSKCs differentiation. Our study indicated the promising potential of AV as a biological macromolecule for stromal tissue regeneration.

Multimodal Structural Analysis of the Human Aorta: From Valve to Bifurcation

The aims of the present study were to assess the relative proportion of collagen and elastin in the arterial wall and to evaluate the collagen microstructure from the aortic root to the external iliac artery. Arterial wall tissue samples sampled during post-mortem examination from 16 sites in 14 individuals without aneurysm disease were fixed and stained for collagen and elastin. Stained sections were imaged and analysed to calculate collagen and elastin content as a percentage of overall tissue area. Scanning electron microscopy was used to quantify the collagen microstructure at six specific arterial regions. From the aortic root to the level of the suprarenal aorta, the percentages (area fractions) of collagen (ascending, descending, and suprarenal aorta respectively with 95% confidence interval [CI] 37.5%, 31.7 – 43.2; 38.9%, 33.1 – 44.7; 44.8%, 37.4 – 52.1) and elastin (43.0%, 37.3 – 48.8; 40.3%, 34.8 – 46.1; 32.4%, 25.2 – 39.6) in the aortic wall were similar. From the suprarenal aorta to the internal iliac arteries, the percentage of collagen increased (abdominal aorta, common and internal iliac arteries and external iliac artery respectively with 95% CI 50.6%, 42.7 – 58.7; 51.2%, 45.5 – 56.9; 49.2%, 42.0 – 56.4) reaching a double percentage for elastin (23.6%, 15.7 – 31.6; 20.8%, 15.1 – 26.5; 22.2%, 14.9 – 29.5). Mean collagen fibre diameter (MFD) and average segment length (ASL) were significantly larger in the external iliac artery (MFD 6.03, 95% CI 5.95 – 6.11; ASL 22.21, 95% CI 20.80 – 23.61) than in the ascending aorta (MFD 5.81, 5.72 – 5.89; ASL 19.47, 18.07 – 20.88) and the abdominal aorta (MFD 5.92, 5.84 – 6.00; ASL 21.10, 19.69 – 22.50). In subjects lacking aneurysmal disease, the aorta and iliac arteries are not structurally uniform along their length. There is an increase in collagen percentage and decrease in elastin percentage progressing distally along the aorta. Mean collagen fibre diameter and average segment length are larger in the external iliac artery, compared with the ascending and the abdominal aorta.

Electrospun Silk Fibroin/kappa-Carrageenan Hybrid Nanofibers with Enhanced Osteogenic Properties for Bone Regeneration Applications.

Simple SummaryBone tissue engineering has recently been considered as a potential alternative approach to treating patients with bone disorders/defects caused by tumors, trauma, and infection. Scaffolds play a crucial role in the field because they can serve as a template that can provide optimal structural and functional support for cells. In this study, we prepared a series of electrospun silk fibroin/kappa-carrageenan nanofibrous membranes with the aim of mimicking bone extracellular matrix structure and composition and improving the biological properties of silk-fibroin-based nanofibers. Our research found that a combinational approach blending kappa-carrageenan and silk fibroin could enhance the biological properties of the nanostructured scaffold. kappa-carrageenan could also enhance the osteogenic potential and bioactivity properties of silk fibroin nanofibers, while genipin crosslinking preserved the mechanical strength of hybrid nanofibrous mats, indicating that the electrospun hybrid scaffolds could be a potential candidate for bone regeneration applications.In this study, a novel nanofibrous hybrid scaffold based on silk fibroin (SF) and different weight ratios of kappa-carrageenan (k-CG) (1, 3, and 5 mg of k-CG in 1 mL of 12 wt% SF solution) was prepared using electrospinning and genipin (GP) as a crosslinker. The presence of k-CG in SF nanofibers was analyzed and confirmed using Fourier transform infrared spectroscopy (FTIR). In addition, X-ray diffraction (XRD) analysis confirmed that GP could cause SF conformation to shift from random coils or α-helices to β-sheets and thereby facilitate a more crystalline and stable structure. The ultimate tensile strength (UTS) and Young’s modulus of the SF mats were enhanced after crosslinking with GP from 3.91 ± 0.2 MPa to 8.50 ± 0.3 MPa and from 9.17 ± 0.3 MPa to 31.2 ± 1.2 MP, respectively. Notably, while the mean fiber diameter, wettability, and biodegradation rate of the SF nanofibers increased with increasing k-CG content, a decreasing effect was determined in terms of UTS and Young’s modulus. Additionally, better cell viability and proliferation were observed on hybrid scaffolds with the highest k-CG content. Osteogenic differentiation was determined from alkaline phosphatase (ALP) activity and Alizarin Red staining and expression of osteogenic marker genes. To this end, we noticed that k-CG enhanced ALP activity, calcium deposition, and expression of osteogenic genes on the hybrid scaffolds. Overall, hybridization of SF and k-CG can introduce a promising scaffold for bone regeneration; however, more biological evaluations are required.

Statistical optimization for preparing nanofibrous mats of polybutylene adipate co‐terephthalate/poly(vinylpyrrolidone) blends by solution blow spinning

AbstractSolution blow spinning (SBS) is used to make poly(butylene‐adipate‐co‐terephthalate) (PBAT) and poly(vinylpyrrolidone) (PVP) blend nanofibers and study the effect of process parameters on their formation. A 34–1 fractional factorial statistical model with three levels and four factors was applied. The factors included the concentration of PVP (wt%) in the PBAT polymer matrix, pressurized air pressure (psi), working distance (cm), and feed rate (ml h−1). The linear and quadratic effects were analyzed using a Pareto chart and verified in a well‐adjusted response surface model. The PVP concentration and working distance had a significant effect on the production of nanofibers. The nanofibrous mats were evaluated by scanning electron microscopy (SEM) and had a mean diameter ranging from 164 to 656 nm. A higher concentration of PVP and a shorter working distance resulted in lower mean fiber diameter. In addition, X‐ray diffraction revealed an increase in the degree of crystallinity of the nanofibrous PBAT due to a greater degree of packing among the polymer molecules. However, the addition of PVP to the polymer matrix is associated with a reduction in the degree of crystallinity of the nanofibrous mat.

Enhancement of Antiwetting Properties of Polystyrene Nanofibrous Membrane by Doping with Graphene Nanoplatelets

Membrane distillation (MD) being an emerging technology, it suffers from many limitations. One of which is the need for membranes with specific characteristics to ensure successful operation and sustainable performance. Membrane wetting phenomenon is one of the significant disadvantages of MD which take place primarily due to membrane pore wetting with the operating liquids. The present work studies the effect of addition of graphene nanoplatelets (GNPs) on enhancing the antiwetting properties of enhanced polystyrene (PS12-SDS) nanofibrous membranes. Results showed that adding 0.5wt% of GNPs to the PS12-SDS polymer matrix enhanced the hydrophobicity of the produced membranes and decreased the mean fiber diameter of the produced membranes by about 5.5% and 36.6%, respectively. The composite (PS12-SDS-GNPs) membrane also showed better salt rejection compared with PS12-SDS at all studied feed flow rates.

Incorporating fingolimod through poly(lactic‐co‐glycolic acid) nanoparticles in electrospun polyurethane/polycaprolactone/gelatin scaffold: An in vitro study for nerve tissue engineering

AbstractFingolimod as a useful drug in nerve regeneration is a promising candidate for promoting axonal regeneration by positively affecting neonatal and adult Schwann cells. Nerve tissue engineering show a novel practical approach by recruiting the scientific methods for creating neural extracellular matrix. In this study, fingolimod was incorporated in polylactic‐co‐glycolic acid and then, an electrospun scaffold composed of polyurethane (PU), polycaprolactone (PCL) and gelatin polymers containing different amount of encapsulated fingolimod (0.01%, 0.02%, and 0.03%) were fabricated. The morphology and microstructure of each scaffold were assessed by scanning electron microscopy (SEM). The physicochemical properties of scaffolds including Fourier transform infrared spectroscopy, mechanical properties, water contact angle, and degradation test were evaluated. MTT assay and also SEM were utilized for the investigation of cell viability and adhesion. The results showed that the mean fiber diameter of scaffold was increased from 151 ± 31 to 243 ± 68 nm followed by increase of fingolimod. Young's modulus was showed all scaffold had in the expected range for nerve tissues. Cell viability assessment proved that PU/PCL/Gel/0.01% fingolimod had a higher cell survival among other groups. The results suggest that PU/PCL/gelatin scaffolds loading from 0.01 fingolimod can be a suitable candidate for peripheral nerve regeneration.