Coaxial Electrospinning Technique Research Articles

Fabrication of Drug-Eluting Polycaprolactone/poly(lactic-co-glycolic Acid) Prolapse Mats Using Solution-Extrusion 3D Printing and Coaxial Electrospinning Techniques.

We developed biodegradable drug-eluting prolapse mats using solution-extrusion 3D printing and coaxial electrospinning techniques. The mats were composed of polycaprolactone (PCL) mesh and lidocaine-, estradiol-, metronidazole-, and connective tissue growth factor (CTGF)-incorporated poly(lactic-co-glycolic acid) (PLGA) nanofibers that mimic the structure of the natural extracellular matrix of most connective tissues. The mechanical properties of degradable prolapse membrane were assessed and compared to commercial non-degradable polypropylene knitted meshes clinically used for pelvic organ prolapse (POP) repair. The release behaviors of the drug-loaded hybrid degradable membranes were also characterized. The experimental results suggest that 3D-printed PCL meshes exhibited comparable strengths to commercial POP meshes and survived through 10,000 cycles of fatigue test without breakage. Hybrid PCL meshes/PLGA nanofibrous membranes provided a sustainable release of metronidazole, lidocaine, and estradiol for 4, 25, and 30 days, respectively, in vitro. The membranes further liberated high levels of CTGF for more than 30 days. The animal tests show that the mechanical property of PCL mesh decreased with time, mainly due to degradation of the polymers post-implantation. No adverse effect of the mesh/nanofibers was noted in the histological images. By adopting solution-extrusion 3D printing and coaxial electrospinning, degradable drug-eluting membranes can be fabricated for POP applications.

Assessment of Antimicrobial Agents, Analgesics, and Epidermal Growth Factors-Embedded Anti-Adhesive Poly(Lactic-Co-Glycolic Acid) Nanofibrous Membranes: In vitro and in vivo Studies.

BackgroundPostoperative tissue adhesion is a major concern for most surgeons and is a nearly unpreventable complication after abdominal or pelvic surgeries. This study explored the use of sandwich-structured antimicrobial agents, analgesics, and human epidermal growth factor (hEGF)-incorporated anti-adhesive poly(lactic-co-glycolic acid) nanofibrous membranes for surgical wounds.Materials and MethodsElectrospinning and co-axial electrospinning techniques were utilized in fabricating the membranes. After spinning, the properties of the prepared membranes were assessed. Additionally, high-performance liquid chromatography and enzyme-linked immunosorbent assays were utilized in assessing the in vitro and in vivo liberation profiles of the pharmaceuticals and the hEGF from the membranes.ResultsThe measured data suggest that the degradable anti-adhesive membranes discharged high levels of vancomycin/ceftazidime, ketorolac, and hEGF in vitro for more than 30, 24, and 27 days, respectively. The in vivo assessment in a rat laparotomy model indicated no adhesion in the peritoneal cavity at 14 days post-operation, demonstrating the anti-adhesive capability of the sandwich-structured nanofibrous membranes. The nanofibers also released effective levels of vancomycin, ceftazidime, and ketorolac for more than 28 days in vivo. Histological examination revealed no adverse effects.ConclusionThe outcomes of this study implied that the anti-adhesive nanofibers with sustained release of antimicrobial agents, analgesics, and growth factors might offer postoperative pain relief and infection control, as well as promote postoperative healing of surgical wounds.

Coaxial electrospun membranes of poly(ε‐caprolactone)/poly(lactic acid) with reverse core‐shell structures loaded with curcumin as tunable drug delivery systems

AbstractNano fibrous membranes core‐shell of poly(lactic acid) (PLA) and poly(ε‐caprolactone) (PCL), encapsulating 1 wt% of curcumin, are fabricated by coaxial electrospinning technique. Morphology and physical properties, as well as the release of curcumin, are studied and compared with neat PLA and PCL individually spinned. Morphological analysis shows for all the samples the obtainment of fiber oriented in random way, without defect and with a narrow distribution of the fiber dimensions (344 nm for PCL fibers and 450 nm for PLA fibers). Mechanical performances and barrier properties are evaluated on all membranes and found to be dependent on the fibers' composition and morphology. Water contact angle for all membranes is found higher than 90° (from 103° for PLA‐Curc to 128° for PCL‐Curc), expected since the hydrophobic behavior of the micro/nano electrospun morphology. The curcumin release from the coaxial fibers, modeled with a modified Weibull equation, shows the possibility of a fine tuning of drug release (up to 15 days) for the produced materials, depending on the required application.

Design and In Vitro Study of a Dual Drug-Loaded Delivery System Produced by Electrospinning for the Treatment of Acute Injuries of the Central Nervous System.

Vascular and traumatic injuries of the central nervous system are recognized as global health priorities. A polypharmacology approach that is able to simultaneously target several injury factors by the combination of agents having synergistic effects appears to be promising. Herein, we designed a polymeric delivery system loaded with two drugs, ibuprofen (Ibu) and thyroid hormone triiodothyronine (T3) to in vitro release the suitable amount of the anti-inflammation and the remyelination drug. As a production method, electrospinning technology was used. First, Ibu-loaded micro (diameter circa 0.95–1.20 µm) and nano (diameter circa 0.70 µm) fibers were produced using poly(l-lactide) PLLA and PLGA with different lactide/glycolide ratios (50:50, 75:25, and 85:15) to select the most suitable polymer and fiber diameter. Based on the in vitro release results and in-house knowledge, PLLA nanofibers (mean diameter = 580 ± 120 nm) loaded with both Ibu and T3 were then successfully produced by a co-axial electrospinning technique. The in vitro release studies demonstrated that the final Ibu/T3 PLLA system extended the release of both drugs for 14 days, providing the target sustained release. Finally, studies in cell cultures (RAW macrophages and neural stem cell-derived oligodendrocyte precursor cells—OPCs) demonstrated the anti-inflammatory and promyelinating efficacy of the dual drug-loaded delivery platform.

MgO Nanoparticles-Incorporated PCL/Gelatin-Derived Coaxial Electrospinning Nanocellulose Membranes for Periodontal Tissue Regeneration.

Electrospinning technique has attracted considerable attention in fabrication of cellulose nanofibrils or nanocellulose membranes, in which polycaprolactone (PCL) could be used as a promising precursor to prepare various cellulose nanofibril membranes for periodontal tissue regeneration. Conventional bio-membranes and cellulose films used in guided tissue regeneration (GTR) can prevent the downgrowth of epithelial cells, fibroblasts, and connective tissue in the area of tooth root but have limitations related to osteogenic and antimicrobial properties. Cellulose nanofibrils can be used as an ideal drug delivery material to encapsulate and carry some drugs. In this study, magnesium oxide (MgO) nanoparticles-incorporated PCL/gelatin core-shell nanocellulose periodontal membranes were fabricated using coaxial electrospinning technique, which was termed as Coaxial-MgO. The membranes using single-nozzle electrospinning technique, namely Blending-MgO and Blending-Blank, were used as control. The morphology and physicochemical property of these nanocellulose membranes were characterized by scanning electron microscopy (SEM), energy-dispersive spectrum of X-ray (EDS), transmission electron microscopy (TEM), contact angle, and thermogravimetric analysis (TGA). The results showed that the incorporation of MgO nanoparticles barely affected the morphology and mechanical property of nanocellulose membranes. Coaxial-MgO with core-shell fiber structure had better hydrophilic property and sustainable release of magnesium ion (Mg2+). CCK-8 cell proliferation and EdU staining demonstrated that Coaxial-MgO membranes showed better human periodontal ligament stem cells (hPDLSCs) proliferation rates compared with the other group due to its gelatin shell with great biocompatibility and hydrophilicity. SEM and immunofluorescence assay results illustrated that the Coaxial-MgO scaffold significantly enhanced hPDLSCs adhesion. In vitro osteogenic and antibacterial properties showed that Coaxial-MgO membrane enhanced alkaline phosphatase (ALP) activity, formation of mineralized nodules, osteogenic-related genes [ALP, collagen type 1 (COL1), runt-related transcription factor 2 (Runx2)], and high antibacterial properties toward Escherichia coli (E. coli) and Actinobacillus actinomycetemcomitans (A. a) when compared with controls. Our findings suggested that MgO nanoparticles-incorporated coaxial electrospinning PCL-derived nanocellulose periodontal membranes might have great prospects for periodontal tissue regeneration.

Thermal Analysis of Organic and Nanoencapsulated Electrospun Phase Change Materials

Latent heat stored in phase change materials (PCM) can greatly improve energy efficiency in indoor heating/cooling applications. This study presents the materials and methods for the formation and characterization of a PCM layer for a latent heat thermal energy storage (LHTES) application. Four commercially available PCMs comprising the classes of organic paraffins and organic non-paraffins were selected for thermal storage application. Pure organic PCM and PCM in water emulsions were experimentally investigated. PCM electrospun microfibers were produced by a co-axial electrospinning technique, where solutions of Polycaprolactone (PCL) 9% w/v and 12% w/v in dichloromethane (DCM) were used as the fiber shell materials. PCM emulsified with sodium dodecyl sulfate (SDS), and Polyvinylalcohol 10% w/v (PVA) constituted the core of the fibers. The thermal behavior of the PCM, PCM emulsions, and PCM electrospun fibers were analyzed with differential scanning calorimetry (DSC). A commercial organic paraffin with a phase change temperature of 18 °C (RT 18) in its pure and emulsified forms was found to be a suitable PCM candidate for LHTES. The PVA-PCM electrospun fiber matrix of the organic paraffin RT18 with a PCL concentration of 12% w/v showed the most promising results leading to an encapsulation efficiency of 67%.

Bioresorbable, electrospun nonwoven for delayed and prolonged release of temozolomide and nimorazole

Glioblastoma multiforme is the most aggressive and lethal form of brain tumour due to the high degree of cancer cells infiltration into surrounding brain tissue. No form of monotherapy can guarantee satisfactory patient outcomes and is only of palliative importance. To find a potential option of glioblastoma treatment the bioresorbable, layer nonwoven mats for controlled temozolomide and nimorazole release were obtained by classical and coaxial electrospinning. Optimization of fibre structure that enables delayed and controlled drug release was performed. The studied bioresorbable polymers were poly(L-lactide-co-ε-caprolactone) and poly(L-lactide-co-glycolide-co-trimethylene carbonate). The physicochemical properties of polymers were determined as well as drug release profiles of nonwoven mats. A combination of coaxial electrospinning and electrospray technique provided three-phased release profiles of temozolomide and nimorazole: the slow release of very low drug doses followed by accelerated release and saturation phase. Results form the basis for further investigation since both studied polymers possess a great potential as nimorazole and temozolomide delivery systems in the form of layered nonwoven implants.

Double enhanced energy storage density via polarization gradient design in ferroelectric poly(vinylidene fluoride)-based nanocomposites

Encapsulating ferroelectric ceramic nanofillers into polymer matrix with various architectures has been demonstrated as an effective strategy for ultrahigh energy storage density. Nevertheless, large discrepancy in permittivities between ceramic fillers and polymer requires sophisticated interfacial modification to alleviate local charge concentration. The idea to design graded permittivity from the filler center to surrounding matrix in composites is promising, yet remains a big challenge. Here coaxial electrospinning technique has been employed to control the polarization gradient distribution in TiO2 nanofibers (TOnf) and poly(vinylidene fluoride)/poly(vinylidene fluoride-co-trifluoroethylene) [PVDF/P(VDF-TrFE)] core-shell structured hybrid nanocomposites system where TOnf is fixed at volume fraction 2%, and the polarization gradient of the polymer is adjusted via altering the volume ratios of PVDF and P(VDF-TrFE) in the coaxial electrospun polymer blends in two layers, respectively. Compared with nanocomposites made from mixed solution electrospun randomly and oriented TOnf-PVDF/P(VDF-TrFE) at the same constituent volume fraction, the dielectric losses of coaxial-spun films decrease more than twice, from 0.087 for random nanocomposite film to 0.028, and more intriguingly, the discharged energy storage density (Ue) doubled increasing from 6.5 J cm−3 for random nanocomposite film to 12.7 J cm−3 for coaxial electrospun film with medium polarization gradient. Finite element analyses reveal the polarization and local electric field distribution in the nanocomposites with various polarization gradient design, and the results unambiguously demonstrate that Ue can be significantly boosted via controlled polarization gradient design.

The effect of shell thickness on gas sensing properties of core-shell fibers

Cr2O3-TiO2 core-shell fibers (Cr-Ti CS-Fs) with different shell thicknesses were synthesized by a facile coaxial electrospinning technique. The gas-sensitive performance of Cr-Ti CS-Fs to acetone was enhanced by optimizing the TiO2 shell thickness. With the increase of the thickness of the TiO2 shell, the response of Cr-Ti CS-Fs to acetone showed a transition from p-type to n-type. Besides, the formation of Cr2O3-TiO2 heterojunction enabled the gas sensors to possess short response and recovery time to target gas. A possible mechanism of the enhancement of gas-sensitive performance of core-shell Fs was also illustrated.

Synthesis of vinyl ester resin-carrying PVDF green nanofibers for self-healing applications

Self-healing on the engineering applications is smart, decisive research for prolonging the life span of the materials and the innovations have been mounting still smarter. Connecting to advancements in self-healing carriers, in altering the chemical structure by optimizing the brittleness for self-healing performance and introducing the bio-degradability, for the first time TPS was blended to PVDF for the synthesis of nanofibers, as carriers of a vinyl ester (VE) resin (medication), by the coaxial electrospinning technique. TPS was mechanically mixed with PVDF base polymer and optimized the TPS content (10 wt%) based on mechanical performance. The novel nanofibers were characterized via field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy, X-ray diffraction, thermal, moisture analysis, and a mechanical line with FESEM and energy-dispersive X-ray analysis studied the self-healing. The TPS/PVDF fibers having hydrogen bonding and increased the crystallinity (40.57 → 44.12%) and the diameter (115 → 184 nm) along with the surface roughness of the fibers with increasing the TPS content. Microanalysis presented the flow-out of the VE resin at the scratched parts in the pierced fibers; interestingly, after some time, the etched part was cured automatically by the curing of the spread resin. Mechanical stretching of the nanofibers in the tensile tests up in the plastic region showed a decrement in the elasticity (TPS/PVDF fibers) and an increment in the brittle nature (cured VE resin) with the increase in Young’s modulus at each stretching, clearly elucidating the healing performance.

Composites of SnSb Nanoparticles Embedded in Porous Carbon Nanofibers Wrapped with Reduced Graphene Oxide for Sodium Storage

Alloying-type anode materials are hopeful candidates for sodium (Na)-ion batteries (SIBs) because of their high theoretical capacity by forming Na-rich intermetallic compounds. However, the huge volume changes lead to serious aggregation and crushing of active materials during the cycling process, resulting in a rapid decay in the capacity of the electrode materials. Herein, we report the manufacture of reduced graphene oxide wrapped on the surface of tin–antimony/nitrogen-doped porous carbon nanofibers (SnSb/N-PCNFs/rGO) by a coaxial electrospinning technique and subsequent annealing treatment. The cooperative effect of rGO and PCNFs can greatly relieve the volume expansion of the SnSb alloy in the cycling process and offer more insertion sites for Na+ ions, thus significantly improving the electrochemical performance. As a SIB anode, the SnSb/N-PCNFs/rGO composite exhibits better reversible capacity (maintaining 416 mAh g–1 at 100 mA g–1 after 120 cycles), excellent rate performance, and marvelous cycle performance (up to 303 mAh g–1 at 2000 mA g–1 after 1000 cycles), making it a hopeful anode candidate for SIBs.

Electrospun microfibers with embedded leuco dye-based thermochromic material for textile applications

Electrospinning is an inexpensive and versatile technique for fabricating micro- and nano- scaled fibers. There have been limited attempts to employ it for the fabrication of thermochromic (TC) fibers, and the fabrication of a three-component (dye, developer, and solvent) TC material has required the use of a more complicated coaxial electrospinning technique. Herein, a simple and novel method for creating thermochromic fibers by electrospinning single strands of poly (methyl methacrylate) (PMMA) with embedded thermochromic powder of a polymer encapsulated three-component system was employed. Unlike past leuco dye-based thermochromic fibers, an unmodified syringe tip can be used for the spinning process and only one flow rate needs to be determined. A solution of solvent (either N-dimethylformamide or chloroform), PMMA, and a commercially available black thermochromic powder was prepared and spun using a custom-made electrospinning apparatus. The spun fibers exhibited a clear color transition from grey to white and had average diameters of 2.53 µm and 1.96 µm for chloroform and N-dimethylformamide based fibers, respectively. The fibers were characterized by scanning electron and optical microscopy to determine their morphology, Fourier transform infrared spectroscopy to determine their chemical composition, and differential scanning calorimetry and thermogravimetric analysis to characterize their thermal properties.

Retinoic acid –loaded core-shell fibrous scaffold for neuronal differentiation of trabecular mesenchymal stem cells

Objective(s): Scientists believe that they can fabricate a biochemical scaffold and seed stem cells on it to create an extracellular matrix for tissue generation. This study sought to develop retinoic acid (RA)-loaded core-shell fibrous scaffolds (Poly-Caprolactone (PCL)/Polyethylene Oxide (PEO) based on electrospinning technique, to examine neural differentiation of trabecular mesenchymal stem cells (TM-MSCs). Materials and Methods: PEO-PCL core- shell fibrous scaffold was fabricated using coaxial electrospinning and Fourier transform infrared (FTIR) used to evaluate the chemical bond structure, scanning electron microscopy (SEM) has been utilized to evaluate surface topography and fibrous diameter, and transient electron microscopy (TEM) to evaluate core-shell structure. The neural differentiation was evaluated using Real-Time PCR.Results: The results of FTIR, SEM, and TEM confirm the fabrication of core-shell fibrous of PEO-PCL. The fabricated scaffold provides a suitable substrate for adhesion, cell proliferation, and differentiation. SEM images show changes in the morphology of TM-MSCs to neuronal cells. A sustained release of RA from the PEO/PCL scaffold was detected over 14 days. In addition, quantifying the expression of the gene indicates an increase in the gene expression of microtubule-associated protein 2 (MAP-2) gene.Conclusion:The PEO/PCL core-shell fibrous scaffold containing a RA constructed using coaxial electrospinning technique was a suitable substrate for inducing neuronal differentiation of TM-MSCs cultivated on core-shell scaffold.

Coaxial electrospun membranes with thermal energy storage and shape memory functions for simultaneous thermal/moisture management in personal cooling textiles

Developing textiles with simultaneous thermal regulation capability and adaptive moisture permeability is of great significance for not only reducing energy consumption but also enhancing personal comfort. To meet the above requirements, coaxial electrospun microfibers based on polyurethane (PU) and polyethylene glycol (PEG) were fabricated, in which PU worked as a supporting shell and PEG worked as an energy-storage core. The coaxial electrospinning technique made PEG to be uniformly encapsulated inside the microfibers to form a ‘core-shell’-like structure, imparting the membranes with a high phase change enthalpy (60.4 J/g), good encapsulation effect, thermal energy storage property and robust mechanical property (sustaining 125 times mass of load). Furthermore, the PU/PEG porous membranes exhibit excellent thermal-actuated shape memory effect, which enables macroscopic shape deformation and adaptive micropore geometry upon heating. The PU/PEG membranes with both thermal regulation capability and temperature-sensitive moisture permeability can generate excellent cooling and drying performances (7.6 °C cooler and better breathability than commercial cotton textile). Therefore, our work may provide a new strategy to design smart textiles with dynamic thermal and moisture management functions for improving the comfort of wearers under hot situations.

New Oral Coaxial Nanofibers forGadodiamide-Prospective Intestinal Magnetic Resonance Imagingand Theranostic.

PurposeGadodiamide (GDD) is a widely used magnetic resonance imaging (MRI) contrast agent. It is available only as intravenous injection. Unfortunately, it exhibits a high renal toxicity. In this respect, the author investigated the possibility of developing nanofibers (NFs, one-dimensional (1D) nanostructures) of GDD that would be promising for oral administration in intestinal imaging. NFs are prepared by electrospinning technique in which a strong electrostatic field is applied on a polymer solution.MethodsNFs were prepared by coaxial electrospinning technique using Eudragit S100 (ES 100) as a shell layer and GDD loaded with polyvinylpyrrolidone K90 (PVP K90) and hydroxypropyl-beta-cyclodextrin (HP-β-CyD) as core fibers. Compatibility study of the NFs ingredients was attested through ATR and DSC investigations. Thermogravimetric analysis of NFs was done to insure its stability. In vitro release of GDD in the intestinal medium with different pH values was measured. In vitro cytotoxicity test was done to prove its safety. Additionally, stability of NFs to perform its function was examined by X-ray.ResultsNFs experienced high entrapment efficiency of about 94.3% ± 3.1%. The ingredients of NFs were compatible through FT-IR and DSC study. The in vitro release data of GDD from coaxial NFs were slow (˂14%) in pH 1.2 till 2 h, while at pH 7.4 it showed burst release of about 12% in the first 2 min. Thermogravimetric analysis proved the NFs are stable. The in vitro cytotoxicity study proved the safety of NFs. Using mammography, the coaxial NFs behaved the same as GDD plain indicating its ability to be a contrasting agent.ConclusionCoaxial NFs of GDD as a core with PVP K90 and HP-β-CyD and ES 100 as a shell were stable and efficient as oral imaging dosage form for the intestine. It might be a prospective theranostic.

Coaxially electrospun PAN/HCNFs@PVDF/UiO-66 composite separator with high strength and thermal stability for lithium-ion battery

Various methods have been used to improve mechanical and thermal performance of electrospun separators in order to implement or scale up their application in batteries. Here a combination of organic & inorganic doping, hot-pressing and coaxial electrospinning technique is employed to develop a [email protected] – PAN/[email protected]/UiO-66 – composite membrane (PAN: polyacrylonitrile, HCNFs: helical carbon nanofibers, PVDF: poly (vinylidene fluoride), UiO-66: a Zr-based Metal-Organic Framework). The [email protected] structure is demonstrated in the electrospun fibers. With the synergetic effect of hot-pressing and the PAN/HCNFs core layer, the fiber membrane can stand tension up to 24.77 MPa. The core layer also helps the electrospun membrane keep intact profile at 200 °C. Besides the HCNFs can support the fibers without serious shape change during the hot-pressing treatment, facilitating retention of high porosity (77.61%). The PVDF/UiO-66 shell layer provides good affinity to electrolyte causing excellent electrochemical performance of lithium ion batteries with the composite membranes.

Core-Shell Nanofibers of Polyvinylidene Fluoride-based Nanocomposites as Piezoelectric Nanogenerators.

Flexible piezoelectric nanogenerators (PENG) are widely applied to harvest sustainable energy from multiple energy sources. The rational and simple design of PENG have great potential in soft electronics. Here we design a highly flexible PENG using the polyvinylidene fluoride (PVDF) and its copolymer, polyvinylidene hexafluoropropylene (PVDF-HFP) with two nanoarchitectures of semiconducting metal oxides, TiO2 and ZnO. The nanotubes of TiO2 and nanoflowers of ZnO are embedded in these different polymeric media by solvent mixing, and new fiber mats are generated by coaxial electrospinning technique. This process aligns the dipoles of polymers and nanomaterials, which is normally a pre-requisite for higher piezo potential. With excellent mechanical strength and flexibility, the tailored lightweight fiber mats are capable of producing good output voltage (a maximum of 14 V) during different mechanical vibrations at various frequencies and in response to human motions. The hybrid nanocomposite PENG is durable and inexpensive and has possible applications in wearable electronics.

CoMn2O4 embedded hollow activated carbon nanofibers as a novel peroxymonosulfate activator

Incorporation of cobalt-manganese oxide into the hollow carbonic framework is a prospective way to synthesize eco-friendly and efficient catalyst/adsorbent for advanced oxidation processes and wastewater treatments. Nonetheless, the complex fabrication process remains a major issue hindering the practical application of carbon-based bimetallic oxide catalyst. Herein, a facile and general method is developed to fabricate novel cobalt manganese oxide embedded hollow activated carbon nanofibers (CoxMn3−xO4/HACNFs, x = 0,1,3) by using coaxial electrospinning technique and subsequent thermal treatment. Among the three CoxMn3−xO4/HACNFs, CoMn2O4/HACNFs exhibited the best catalytic activity in PMS activation and Rhodamine B (RhB) degradation, due to the synergistic effect between spinel oxide and hybridized carbon network. Furthermore, HACNFs significantly improved the durability of CoMn2O4 by preventing metal leaching during PMS activation. A marginal decrease in the performance of used CoMn2O4/HACNFs was observed during five cycles, but the performance could be recovered by a simple calcination. A rational PMS activation mechanism of CoMn2O4/HACNFs was proposed. Benefiting from the unique structural features, CoMn2O4/HACNFs exhibited a superior adsorption and catalytic performance for RhB removal under continuous-flow reaction.

Electrospun Microvasculature for Rapid Vascular Network Restoration.

Sufficient blood supply through neo-vasculature is a major challenge in cell therapy and tissue engineering in order to support the growth, function, and viability of implanted cells. However, depending on the implant size and cell types, the natural process of angiogenesis may not provide enough blood supply for long term survival of the implants, requiring supplementary strategy to prevent local ischemia. Many researchers have reported the methodologies to form pre-vasculatures that mimic in vivo microvessels for implantation to promote angiogenesis. These approaches successfully showed significant enhancement in long-term survival and regenerative functions of implanted cells, yet there remains room for improvement. This paper suggests a proof-of-concept strategy to utilize novel scaffolds of dimpled/hollow electrospun fibers that enable the formation of highly mature pre-vasculatures with adequate dimensions and fast degrading in the tissue. Higher surface roughness improved the maturity of endothelial cells mediated by increased cell-scaffold affinity. The degradationof scaffold material for functional restoration of the neo-vasculatures was also expedited by employing the hollow scaffold design based on co-axial electrospinning techniques. This unique scaffold-basedpre-vasculature can hold implanted cells and tissue constructs for a prolonged time while minimizing thecellular loss, manifesting as a gold standard design for transplantable scaffolds.

Epidermal stimulating factors-gelatin/polycaprolactone coaxial electrospun nanofiber: ideal nanoscale material for dermal substitute

In this study, an ideal nano-scale material, named epidermal stimulating (ES) factors-gelatin/polycaprolactone (GT/PCL) nanofiber, was fabricated using a coaxial electrospinning technique. The ES-GT/PCL nanofibers possessed a highly porous structure with qualified mechanical properties for transplantation. With ES factors stored in the core and GT/PCL in the shell, the ES factors could be protected and released in a sustained manner. After seeding L929 cell line on ES-GT/PCL nanofibers for 7 days in vitro, the proliferation of cells was nearly 1.5 folds compared to the control group. The in vivo study showed that ES-GT/PCL nanofibers can accelerate skin wound healing rate during the healing course, especially on the early stage. The epidermal and dermal thickness, as well as skin appendages and fat tissue, were the most similar to the native skin. These findings provided valuable insights into the addition of multiple bioactive factors to nanometre biomaterials, and optimising the advantages of the compositions as a promising potential dermal substitute construct.