Aligned poly(L-lactide) (PLLA)/poly(?-caprolactone) (PCL)/hydroxyapaite (HA) composite fibrous membranes were fabricated by electrospinning. Their morphology, thermal stability, mechanical properties, hydrophilic properties and biocompatibility were investigated. The electrospun fibers are highly aligned and the HA are oriented along the fiber axis. When HA are incorporated, the PLLA/PCL/HA composite fibers become thinner due to the increased conductivity. In addition, the aligned HA reinforce the electrospun fibrous membranes. The larger porosity and higher hydrophilic properties induced by HA in the electrospun fibers have improved the degradation of the PLLA/PCL/HA fibrous membranes which have no toxic effect on proliferation of adipose-derived stem cells. 相似文献
Polymorphism control of PVDF has been realized through electrospinning. PVDF fibrous membranes with fiber diameter in the range of 100 nm to several micrometers were produced by electrospinning and the crystal phase of electrospun PVDF fibers can be adjusted at the same time. Through the control of electrospinning parameters such as the solvent, electrospinning temperature, feeding rate, and tip‐to‐collector distance, PVDF fibrous membranes containing mainly α‐ or β‐ or γ‐phase could be fabricated successfully.
Electrospun zein membranes were prepared using DMF as solvent. By changing the solution concentration, the electrospinning voltage and the distance between the spinneret and collector, nanofibrous meshes without bead defects could be obtained. In order to improve the mechanical strength of the hydrated zein meshes, core-shell-structured nanofibrous membranes with PCL as the core material and zein forming the shell were prepared by coaxial electrospinning. The core-shell structure of the composite fibers was confirmed by SEM characterization of the fibers, either extracted with chloroform to remove the inner PCL, or elongated to expose their cross-section. The composition and average diameter of the composite fibers could be modulated by the feed rate of the inner PCL solution. It was found that the core-shell fibrous membranes have similar wettability to the electrospun zein mesh. The presence of PCL in the fibers could significantly improve the mechanical properties of the zein membrane. 相似文献
In this work, nanofibrous hydrogel has been fabricated from needleless electrospinning of Poly(acrylic acid) (PAA) in an aqueous solution with different concentrations. First, all solution samples were characterized for pH, surface tension, conductivity and viscosity. Next, electrospinnability of the PAA-water dope solution was investigated using the needleless electrospinning technique under constant conditions. Results indicated that the PAA-water solution was not electrospinnable. Therefore, the neutralization of carboxylic groups in the PAA chemical structure using the NaOH solution was investigated to enhance the PAA electrospinnability. Morphology observation revealed that the fiber diameters ranged from 40 to 250 nm and increased with increasing the solution concentrations. Increasing the neutralization degree (10%, 15% and 20% with 50 wt% NaOH solution) led to increase the dope viscosity and conductivity. The resultant nanofibers could be rendered water-insoluble by incorporating 1,4-butanediol diglycidyl-ether in the PAA-water dope solution, then heat-induced crosslinking was performed using a microwave at different curing times (1–5 min) and temperatures (45–105 °C). The nanofibrous hydrogel mat was then characterized by FTIR. The resulting nanofibrous hydrogel showed remarkable water absorption capacity up to 17,000% and 51,000% (within 15 min) in the standard saline solution and distilled water, respectively. 相似文献
PEG-N-chitosan and PEG-N,O-chitosan were synthesized via reductive amination and acylation of chitosan, respectively. The structures were confirmed
by FTIR and H1NMR. The extents of PEGylation increased with reducing chain lengths of either chitosan (Mv = 137–400 kDa) or poly(ethyelene glycol) (PEG, Mn = 500–2 kDa). Water solubility were easily achieved at degree of substitution (DS) as low as 0.2 for either derivtive whereas the
PEG-N,O-chitosan at DS = 1.5 was soluble in organic solvents, including CHCl3, DMF, DMSO and THF. None of the aqueous solutions of PEG-N-chitosan or PEG-N,O-chitosan alone could be electrospun into fibers. Electrospinning of PEG550-N,O-chitosan145 at 25% in DMF produced fibrous structure intermixed with beads. The efficiency of fiber formation and the uniformity
of fibers were improved by increasing the solution viscosity using a cosolvent or reducing the solution surface tensions with
a non-ionic surfactant. Ultra-fine fibers with diameters ranging from 40 nm to 360 nm and an average diameter of 162 nm were
efficiently generated from electrospinning of 15% PEG550-N,O-chitosan145 in 75/25 (v/v) THF/DMF cosolvents with 0.5% Triton X-100TM. 相似文献
Temperature‐triggered switchable nanofibrous membranes are successfully fabricated from a mixture of cellulose acetate (CA) and poly(N‐isopropylacrylamide) (PNIPAM) by employing a single‐step direct electrospinning process. These hybrid CA‐PNIPAM membranes demonstrate the ability to switch between two wetting states viz. superhydrophilic to highly hydrophobic states upon increasing the temperature. At room temperature (23 °C) CA‐PNIPAM nanofibrous membranes exhibit superhydrophilicity, while at elevated temperature (40 °C) the membranes demonstrate hydrophobicity with a static water contact angle greater than 130°. Furthermore, the results here demonstrate that the degree of hydrophobicity of the membranes can be controlled by adjusting the ratio of PNIPAM in the CA‐PNIPAM mixture.
A facile fabrication of a cross-linked hyaluronic acid (HA) hydrogel nanofibers by a reactive electrospinning method is described. A thiolated HA derivative, 3,3'-dithiobis(propanoic dihydrazide)-modified HA (HA-DTPH), and poly(ethylene glycol) diacrylate (PEGDA) are selected as the cross-linking system. The cross-linking reaction occurs simultaneously during the electrospinning process using a dual-syringe mixing technique. Poly(ethylene oxide) (PEO) is added into the spinning solution as a viscosity modifier to facilitate the fiber formation and is selectively removed with water after the electrospinning process. The nanofibrous structure of the electrospun HA scaffold is well preserved after hydration with an average fiber diameter of 110 nm. A cell morphology study on fibronectin (FN)-adsorbed HA nanofibrous scaffolds shows that the NIH 3T3 fibroblasts migrate into the scaffold through the nanofibrous network, and demonstrate an elaborate three-dimensional dendritic morphology within the scaffold, which reflects the dimensions of the electrospun HA nanofibers. These results suggest the application of electrospun HA nanofibrous scaffolds as a potential material for wound healing and tissue regeneration. [image: see text] Laser scanning confocal microscopy demonstrates that the NIH3T3 fibroblast develops an extended 3D dendritic morphology within the fibronectin-adsorbed electrospun HA nanofibrous scaffold. 相似文献
An optical oxygen sensor based on an EuIII complex/polystyrene (PS) composite nanofibrous membrane is prepared by electrospinning. The emission intensity of [Eu(TTA)3(phencarz)] (TTA=2‐thenoyltrifluoroacetonate, phencarz=2‐(N‐ethylcarbazolyl‐4)imidazo[4,5‐f]1,10‐phenanthroline) decreases with increasing oxygen concentration, and thus the [Eu(TTA)3 (phencarz)]/PS composite nanofibrous membranes can be used as an optical oxygen‐sensing material based on emission quenching caused by oxygen. Elemental analysis, UV/Vis absorption spectra, scanning electron microscopy (SEM), fluorescence microscopy, luminescence‐intensity quenching Stern–Volmer plots, and excited‐state decay analysis are used to characterize the obtained oxygen‐sensing materials. A high sensitivity (IN2/IO2) of 3.38 and short response and recovery times (t↓=5.0, t↑=8.0 s) are obtained. These results are the best values reported for oxygen sensors based on EuIII complexes. The high surface area‐to‐volume ratio and porous structure of the electrospun nanofibrous membranes are taken to be responsible for the outstanding performance. 相似文献
An injectable nanofibrous hydrogel scaffold integrated with growth factors (GFs) loaded polysaccharide nanoparticles was developed that specifically allows for targeted adipose‐derived stem cells (ASCs) encapsulation and soft tissue engineering. The nanofibrous hydrogel was produced via biological conjugation of biotin‐terminated star‐shaped poly(ethylene glycol) (PEG‐Biotin) and streptavidin‐functionalized hyaluronic acid (HA‐Streptavidin). The polysaccharide nanoparticles were noncovalently assembled via electrostatic interactions between low‐molecular‐weight heparin (LMWH) and N,N,N‐trimethylchitosan chloride (TMC). Vascular endothelial growth factor (VEGF) was entrapped in the LMWH/TMC nanoparticles by affinity interactions with LMWH. 相似文献
Bicomponent nanofibers of N-carboxyethylchitosan (CECh) and poly(vinyl alcohol) (PVA) were obtained by electrospinning of mixed aqueous solutions. The electrospinning of CECh-containing nanofibers was enabled by the ability of PVA to form an elastically deformable entanglement network based on hydrogen bonds. The average diameters of the bicomponent fibers were in the range 100-420 nm. Water-resistant nanofibrous mats were obtained by thermal crosslinking at 100 °C for 10 h. Nanofibrous materials with 1D-, 1D-transversery or 3D fiber alignment were obtained depending on the type of the collector used. 相似文献
The properties of mixtures of two polysaccharides, arabinogalactan (AG) and hyaluronic acid (HA), were investigated in solution by the measurement of diffusion coefficients D of water protons by DOSY (Diffusion Ordered SpectroscopY), by the determination of viscosity and by the investigation of the affinity of a small molecule molecular probe versus AG/HA mixtures in the presence of bovine submaxillary mucin (BSM) by 1HNMR spectroscopy. Enhanced mucoadhesive properties, decreased mobility of water and decreased viscosity were observed at the increase of AG/HA ratio and of total concentration of AG. This unusual combination of properties can lead to more effective and long-lasting hydration of certain tissues (inflamed skin, dry eye corneal surface, etc.) and can be useful in the preparation of new formulations of cosmetics and of drug release systems, with the advantage of reducing the viscosity of the solutions. 相似文献