A new nanofiber fabrication technique based on coaxial electrospinning

In tissue engineering, nanofibrous scaffolds can achieve better biological responses than microfibrous scaffolds and electrospinning is a common method for producing fibrous scaffolds. However, not all biopolymers can be made into nanofibers through conventional electrospinning. The current investigation developed an innovative nanofiber fabrication technique based on coaxial electrospinning and used poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) as an example for achieving nanofibers. For obtaining PHBV nanofibers, core-shell structured fibers were fabricated first via coaxial electrospinning, with PHBV being the core and chitosan being the shell. The chitosan shell was then removed by washing electrospun scaffolds with water, leading to the formation of nanofibrous PHBV scaffolds. The PHBV nanofiber diameter was affected by the inner polymer (i.e., PHBV) solution concentration during coaxial electrospinning, which can be explained in terms of the coaxial electrospinning process and polymer solution viscosity. Compared to the approach of using a conductivity-enhancing salt in polymer solution to produce polymer nanofibers, the new technique not only eliminates the biocompatibility concerns but also provides a more effective way of reducing fiber diameters to the nano-size range.     

Electrospun PCL/PLA/HA based nanofibers as scaffold for osteoblast-like cells

Polycaprolactone (PCL), poly (lactic acid) (PLA) and hydroxyapatite (HA) are frequently used as materials for tissue engineering. In this study, PCL/PLA/HA nanofiber mats with different weight ratio were prepared using electrospinning. Their structure and morphology were studied by FTIR and FESEM. FTIR results demonstrated that the HA particles were successfully incorporated into the PCL/PLA nanofibers. The FESEM images showed that the surface of fibers became coarser with the introduction of HA nanoparticles into PCL/PLA system. Furthermore, the addition of HA led to the decreasing of fiber diameter. The average diameters of PCL/PLA/HA nanofiber were in the range of 300-600 nm, while that of PCL/PLA was 776 +/- 15.4 nm. The effect of nanofiber composition on the osteoblast-like MC3T3-E1 cell adhesion and proliferation were investigated as the preliminary biological evaluation of the scaffold. The MC3T3-E1 cell could be attached actively on all the scaffolds. The MTT assay revealed that PCL/PLA/HA scaffold shows significantly higher cell proliferation than PCL/PLA scaffolds. After 15 days of culture, mineral particles on the surface of the cells was appeared on PCL/PLA/HA nanofibers while normal cell spreading morphology on PCL/PLA nanofibers. These results manifested that electrospun PCL/PLA/HA scaffolds could enhance bone regeneration, showing their marvelous prospect as scaffolds for bone tissue engineering.     

Gravity Drawing of Micro‐ and Nanofibers for Additive Manufacturing of Well‐Organized 3D‐Nanostructured Scaffolds

This work introduces a gravity fiber drawing (GFD) method of making single filament nanofibers from polymer solutions and precise alignment of the fibers in 3D scaffolds. This method is advantageous for nanofiber 3D alignment in contrast to other known methods. GFD provides a technology for the fabrication of freestanding filament nanofibers of well‐controlled diameter, draw ratio, and 3D organization with controllable spacing and angular orientation between nanofibers. The GFD method is capable of fabricating complex 3D scaffolds combining fibers with different diameters, chemical compositions, mechanical properties, angular orientations, and multilayer structures in the same construct. The scaffold porosity can be as high as 99% to secure transport of nutrients and space for cell infiltration and differentiation in tissue engineering and 3D cell culture applications.     

Electrospun nanofibers: Work for medicine?

Attempts have been made to fabricate nanofibrous scaffolds to mimic the chemical composition and structural properties of the extracellular matrix (ECM) for tissue/organ replacement. Nanofiber scaffolds with various patterns have been successfully produced from synthetic and natural polymers through a relatively simple technique of electrospinning. The resulting patterns can mimic some of the diverse tissue-specific orientation and three-dimensional (3D) fibrous structures. Studies on cell-nanofiber interactions, including studies on stem cells, have revealed the importance of nanotopography on cell adhesion, proliferation and differentiation. Furthermore, clinical application of electrospun nanofibers including wound healing, tissue regeneration, drug delivery and stem cell therapy are highly feasible due to the ease and flexibility of fabrication of making nanofiber with this cost-effective method using electrospinning. In this review, we have highlighted the current state of the art and provided future perspectives on electrospun nanofiber in medical applications.     

Surface modified electrospun nanofibrous scaffolds for nerve tissue engineering

The development of biodegradable polymeric scaffolds with surface properties that dominate interactions between the material and biological environment is of great interest in biomedical applications. In this regard, poly-ε-caprolactone (PCL) nanofibrous scaffolds were fabricated by an electrospinning process and surface modified by a simple plasma treatment process for enhancing the Schwann cell adhesion, proliferation and interactions with nanofibers necessary for nerve tissue formation. The hydrophilicity of surface modified PCL nanofibrous scaffolds (p-PCL) was evaluated by contact angle and x-ray photoelectron spectroscopy studies. Naturally derived polymers such as collagen are frequently used for the fabrication of biocomposite PCL/collagen scaffolds, though the feasibility of procuring large amounts of natural materials for clinical applications remains a concern, along with their cost and mechanical stability. The proliferation of Schwann cells on p-PCL nanofibrous scaffolds showed a 17% increase in cell proliferation compared to those on PCL/collagen nanofibrous scaffolds after 8 days of cell culture. Schwann cells were found to attach and proliferate on surface modified PCL nanofibrous scaffolds expressing bipolar elongations, retaining their normal morphology. The results of our study showed that plasma treated PCL nanofibrous scaffolds are a cost-effective material compared to PCL/collagen scaffolds, and can potentially serve as an ideal tissue engineered scaffold, especially for peripheral nerve regeneration.     

Impact of Scaffold Micro and Macro Architecture on Schwann Cell Proliferation under Dynamic Conditions in a Rotating Wall Vessel Bioreactor

Over the last decade tissue engineering has emerged as a powerful alternative to regenerate lost tissues owing to trauma or tumor. Evidence shows that Schwann cell containing scaffolds have improved performance in vivo as compared to scaffolds that depend on cellularization post implantation. However, owing to limited supply of cells from the patients themselves, several approaches have been taken to enhance cell proliferation rates to produce complete and uniform cellularization of scaffolds. The most common approach is the application of a bioreactor to enhance cell proliferation rate and therefore reduce the time needed to obtain sufficiently significant number of glial cells, prior to implantation.In this study, we show the application of a rotating wall bioreactor system for studying Schwann cell proliferation on nanofibrous spiral shaped scaffolds, prepared by solvent casting and salt leaching techniques. The scaffolds were fabricated from polycaprolactone (PCL), which has ideal mechanical properties and upon degradation does not produce acidic byproducts. The spiral scaffolds were coated with aligned or random nanofibers, produced by electrospinning, to provide a substrate that mimics the native extracellular matrix and the essential contact guidance cues.At the 4 day time point, an enhanced rate of cell proliferation was observed on the open structured nanofibrous spiral scaffolds in a rotating wall bioreactor, as compared to static culture conditions. However, the cell proliferation rate on the other contemporary scaffolds architectures such as the tubular and cylindrical scaffolds show reduced cell proliferation in the bioreactor as compared to static conditions, at the same time point. Moreover, the rotating wall bioreactor does not alter the orientation or the phenotype of the Schwann cells on the aligned nanofiber containing scaffolds, wherein, the cells remain aligned along the length of the scaffolds. Therefore, these open structured spiral scaffolds pre-cultured with Schwann cells, in bioreactors could potentially shorten the time needed for grafts for peripheral nerve regeneration.     

Preparation and characterization of electrospun poly(ε-caprolactone)-poly(l-lactic acid) nanofiber tubes

Recently, attempts have been made to develop nanofiber tubes suitable for nerve regeneration made of biodegradable nanofibers. Among all polymeric nanofibers, poly(ε-caprolactone) (PCL) is distinctively known for better mechanical stability and poly(l-lactic acid) (PLLA) for relatively faster biodegradability. Our purpose of study is to investigate their blending compatibility and the ability to form nanofiber tubes via electrospinning. We electrospun the PCL–PLLA nanofiber tubular using different blend ratios of PCL–PLLA. The electrospun nanofibers were continuously deposited over high speed rotating mandrel to fabricate nanofiber tubes having inner diameter of 2 mm and the wall thickness of 55–65 μm. The diameters of nanofibers were between 715 and 860 nm. The morphologies of PCL–PLLA nanofiber tubes were examined under scanning electron microscope, and showed better structural stability and formability than the neat PLLA nanofibers. Fourier transform infrared spectroscopy study revealed that the PCL–PLLA blend nanofiber exhibited characteristic peaks of both PCL and PLLA and was composition-dependent. Raman and X-ray diffraction studies showed that the increasing PCL ratio in the PCL–PLLA blend increased crystallinity of PCL–PLLA blends. Differential scanning calorimetry revealed recrystallization peaks in PCL–PLLA blends ratios of 1:2 and 1:1. Based on characterization, the electrospun PCL–PLLA nanofiber tubes is considered to be a better candidate for further in vivo or in vitro investigation, and resolve biocompatibility issues in tissue engineering.     

Adipose-derived stem cells could sense the nano-scale cues as myogenic-differentiating factors

Microenvironmental cues, such as surface topography and substrate stiffness, may affect stem cells adhesion, morphology, alignment, proliferation and differentiation. Adipose derived stem cells (ASCs) have attracted considerable interest in regenerative medicine due to their easy isolation, extensive in vitro expandability and ability to differentiate along a number of different tissue-specific lineages. The aim of this work was to investigate ASCs adhesion, alignment and differentiation into myogenic lineage on nanofibrous polymeric scaffolds with anisotropic topography. Nanostructured scaffolds with randomized or parallel fibers were fabricated by electrospinning using polycaprolactone (PCL) and the polycarbonate-urethane ChronoFlex AL 80A (CFAL). Cells expressed myosin (fast skeletal) and tropomyosin in all surface topographies 7 days after seeding but myotube formation was only observed on CFAL scaffolds and only few myotubes were formed on PCL scaffolds. The different cell behavior could be ascribed to two main parameters: fibers dimensions and fibers orientation of the substrates that could result in a better myotube formation on CFAL scaffolds.     

Effect of electrospinning parameters on the nanofiber diameter and length

Polymer nanofibers exhibit properties that make them a favorable material for the development of tissue engineering scaffolds, filtration devices, sensors, and high strength lightweight materials. Electrospinning is a versatile method commonly used to manufacture polymer nanofibers. Collection of electrospun nanofibers across two parallel plates is a technique useful for creating nanofiber structures because it allows for the collection of linearly oriented individual nanofiber arrays and these arrays can be easily transferred to other substrates or structures. It is of importance to have some understanding of the capabilities of this collection method, such as the maximum length of fibers that can be collected across two parallel plates. The effect of different electrospinning parameters on maximum fiber length, average fiber diameter, diameter uniformity, and fiber quality was explored. It was shown that relatively long continuous polycaprolactone (PCL) nanofibers with average diameters from approximately 350 nm to 1 μm could be collected across parallel plates at lengths up to 35-50 cm. Experimental results lead to the hypothesis that even longer continuous nanofibers over 50 cm could be collected if the size of the parallel plates were increased. Extending the maximum fiber length that can be collected across parallel plates could expand the applications of electrospinning. Polymer solution concentration, plate size, and applied voltage were all shown to have varying effects on maximum fiber length, fiber diameter, and fiber uniformity.     

Fabrication,characterization and in vitro drug release behavior of electrospun PLGA/chitosan nanofibrous scaffold

In this study both aligned and randomly oriented poly(d,l-lactide-co-glycolide) (PLGA)/chitosan nanofibrous scaffold have been prepared by electrospinning. The ratio of PLGA to chitosan was adjusted to get smooth nanofiber surface. Morphological characterization using scanning electron microscopy showed that the aligned nanofiber diameter distribution obtained by electrospinning of polymer blend increased with the increase of chitosan content which was similar to that of randomly oriented nanofibers. The release characteristic of model drug fenbufen (FBF) from the FBF-loaded aligned and randomly oriented PLGA and PLGA/chitosan nanofibrous scaffolds was investigated. The drug release rate increased with the increase of chitosan content because the addition of chitosan enhanced the hydrophilicity of the PLGA/chitosan composite scaffold. Moreover, for the aligned PLGA/chitosan nanofibrous scaffold the release rate was lower than that of randomly oriented PLGA/chitosan nanofibrous scaffold, which indicated that the nanofiber arrangement would influence the release behavior. In addition, crosslinking in glutaraldehyde vapor would decrease the burst release of FBF from FBF-loaded PLGA/chitosan nanofibrous scaffold with a PLGA/chitosan ratio less than 9/1, which would be beneficial for drug release.     

Novel 3D scaffold with enhanced physical and cell response properties for bone tissue regeneration,fabricated by patterned electrospinning/electrospraying

Developing three dimensional scaffolds mimicking the nanoscale structure of native extracellular matrix is a key parameter in tissue regeneration. In this study, we aimed to introduce a novel 3D structures composed of nanofibers (NF) and micro particles (MP) and compare their efficiency with 2D nanofibrous scaffold. The conventional nanofibrous PCL scaffolds are 2D mats fabricated by the electrospinning technique, whereas the NF/MP and patterned NF/MP PCL scaffolds are three dimensional structures fabricated by a modified electrospinning/electrospraying technique. The mentioned method was carried out by varying the electrospinning solution parameters and use of a metal mesh as the collector. Detailed fabrication process and morphological properties of the fabricated structures is discussed and porosity, pore size and PBS solution absorption value of the prepared structures are reported. Compared with the 2D structure, 3D scaffolds possessed enhanced porosity and pore size which led to the significant increase in their water uptake capacity. In vitro cell experiments were carried out on the prepared structures by the use of MG-63 osteosarcoma cell line. The fabricated 3D structures offered significantly increased cell attachment, spread and diffusion which were confirmed by SEM analysis. In vitro cytocompatibility assessed by MTT colorimetric assay indicated a continuous cell proliferation over 21 days on the innovative 3D structure, while on 2D mat cell proliferation stopped at early time points. Enhanced osteogenic differentiation of the seeded MG-63 cells on 3D scaffold was confirmed by the remarkable ALP activity together with increased and accelerated calcium deposition on this structure compared to 2D mat. Massive and well distributed bone minerals formed on patterned 3D structure were shown by EDX analysis. In comparison between NF/MP quasi-3D and Patterned NF/MP 3D scaffolds, patterned structures proceeded in all of the above properties. As such, the innovative Patterned NF/MP 3D scaffold could be considered as a proper bone graft substitute for bone tissue regeneration.     

Nanofibrous membrane of collagen–polycaprolactone for cell growth and tissue regeneration

Nanofibrous substrates of synthetic polymers including polycaprolactone (PCL) have shown considerable potential in tissue regeneration. This paper reports the use of PCL/collagen nanofibers to improve the in vitro osteoblastic responses for the applications in bone regeneration area. Collagen and PCL were dissolved in a co-solvent, and the resulting solution was electrospun into a nanofibrous web. Nonwoven fibrous matrices were successfully produced at various compositional ratios (PCL/collagen = 1/3, 1 and 3 by weight). Although the PCL nanofiber was hydrophobic, the presence of collagen significantly improved the water affinity, such as the water contact angle and water uptake capacity. Tensile mechanical tests showed that the collagen–PCL nanofiber had a significantly higher extension rate (approximately 2.8-fold) than the PCL while maintaining the maximum tensile load in a similar range. The osteoblastic cells cultured on the collagen–PCL nanofibrous substrate showed better initial adhesion and a higher level of growth than those cultured on the PCL nanofiber. Furthermore, real-time RT-PCR revealed the expression of a series of bone-associated genes, including osteopontin, collagen type I and alkaline phosphatase. The expression of these genes was significantly higher on the collagen–PCL nanofiber than on the PCL nanofiber. When subcutaneously implanted in mouse the collagen–PCL membrane facilitated tissue cells to well penetrate into the nanofibrous structure at day 7, whilst no such cell penetration was noticed in the pure PCL nanofiber. Overall, the presence of collagen within the PCL nanofiber improves the water affinity, tensile extension rate, and the tissue cell responses, such as initial adhesion, growth, penetration and the expression of bone-associated genes. Therefore, the collagen–PCL nanofibrous membrane may have potential applications in the cell growth and bone tissue regeneration.     

Fabrication and characterization of three-dimensional nanofiber membrance of PCL–MWCNTs by electrospinning

The uniform and highly smooth nanofibers of poly(ε-caprolactone) (PCL) composited with different multi-walled carbon nanotubes (MWCNTs) content (ranging from 0.1 wt.% to 5 wt.%) were successfully prepared by electrospinning method without the occurrence of bead defects in this study. The PCL–0.5 wt.%MWCNTs nanofiber membrane exhibited the maximum tensile strength (about 1.42 MPa), which was increased by 46% compared with that of electrospun pure PCL nanofiber membrane. Moreover, the PCL–MWCNTs nanofiber membrane exhibited three-dimensional porous structure with a high porosity over 90%. The average diameter of PCL–MWCNTs nanofibers decreased with the addition of MWCNTs and there was a narrow diameter distribution in the range of 52–244 nm when the amount of MWCNTs was 0.5 wt.%. Compared with pure PCL nanofibers, PCL–MWCNTs nanofibers showed accelerating degradation behavior. In addition, the cytotoxicity results revealed that the electrospun PCL–MWCNTs nanofiber membranes possessed good in vitro biocompatibility, and hemolysis and kinetic clotting tests indicated that the PCL nanofiber membranes did not enhance blood coagulation after the addition of MWCNTs. It can be concluded that such kind of electrospun PCL–MWCNTs nanofibers may be promising candidate for tissue engineering scaffold application.     

Fabrication of hierarchical polycaprolactone/gel scaffolds via combined 3D bioprinting and electrospinning for tissue engineering

It is a severe challenge to construct 3D scaffolds which hold controllable pore structure and similar morphology of the natural extracellular matrix(ECM).In this study,a compound technology is proposed by combining the 3D bioprinting and electrospinning process to fabricate 3D scaffolds,which are composed by orthogonal array gel microfibers in a grid-like arrangement and intercalated by a nonwoven structure with randomly distributed polycaprolactone(PCL) nanofibers.Human adiposederived stem cells(hASCs) are seeded on the hierarchical scaffold and cultured 21 d for in vitro study.The results of cells culturing show that the microfibers structure with controlled pores can allow the easy entrance of cells and the efficient diffusion of nutrients,and the nanofiber webs layered in the scaffold can significantly improve initial cell attachment and proliferation.The present work demonstrates that the hierarchical PCL/gel scaffolds consisting of controllable 3D architecture with interconnected pores and biomimetic nanofiber structures resembling the ECM can be designed and fabricated by the combination of 3D bioprinting and electrospinning to improve biological performance in tissue engineering applications.     

Seamless, axially aligned, fiber tubes, meshes, microbundles and gradient biomaterial constructs

A new electrospinning apparatus was developed to generate nanofibrous materials with improved organizational control. The system functions by oscillating the deposition signal (ODS) of multiple collectors, allowing significantly improved nanofiber control by manipulating the electric field which drives the electrospinning process. Other electrospinning techniques designed to impart deposited fiber organizational control, such as rotating mandrels or parallel collector systems, do not generate seamless constructs with high quality alignment in sizes large enough for medical devices. In contrast, the ODS collection system produces deposited fiber networks with highly pure alignment in a variety of forms and sizes, including flat (8?×?8?cm²), tubular (1.3?cm diameter), or rope-like microbundle (45?μm diameter) samples. Additionally, the mechanism of our technique allows for scale-up beyond these dimensions. The ODS collection system produced 81.6?% of fibers aligned within 5° of the axial direction, nearly a four-fold improvement over the rotating mandrel technique. The meshes produced from the 9?% (w/v) fibroin/PEO blend demonstrated significant mechanical anisotropy due to the fiber alignment. In 37?°C PBS, aligned samples produced an ultimate tensile strength of 16.47?±?1.18?MPa, a Young’s modulus of 37.33?MPa, and a yield strength of 7.79?±?1.13?MPa. The material was 300?% stiffer when extended in the direction of fiber alignment and required 20 times the amount of force to be deformed, compared to aligned meshes extended perpendicular to the fiber direction. The ODS technique could be applied to any electrospinnable polymer to overcome the more limited uniformity and induced mechanical strain of rotating mandrel techniques, and greatly surpasses the limited length of standard parallel collector techniques.     

Wet chemical process to enhance osteoconductivity of electrospun chitosan nanofibers

In this study, chitosan/hydroxyapatite (CS/HA) nanofibers were prepared using a wet chemical method. First, CS nanofibers with uniform diameters were fabricated using electrospinning. Then, a wet chemical process was used to mineralize nanofiber surfaces to form a homogeneous HA deposit. Reactions with three cycles were found to optimize biomimetic properties of the HA. The mineralization process required only approximately 3 h, which corresponded to a saving of 98 % in preparation time compared with that needed by the process using a simulated body fluid (SBF). According to the attachment and spreading of UMR (rat osteosarcoma) cells on the CS/HA composite fibers, the deposited mineralization layer significantly enhanced cell affinity of the CS nanofibers and the HA created by the wet chemical method was as effective as that created by the SBF. The composite nanofibrous scaffolds produced by the wet chemical process also promoted osteogenic differentiation by inducing ossification. Thus, expressions of collagen type I, alkaline phosphatase, osteocalcin, bone sialoprotein, and osterix were all enhanced. These results demonstrated that composite electrospun fibers can be efficiently prepared using wet chemical method and the resulting nanofibrous scaffolds have considerable potential in future bone tissue engineering applications.     

静电纺丝天然-人工合成聚合物复合纳米纤维及其对细胞黏附、增殖和迁移的影响

生物材料组成成分对细胞生物功能有不同的影响。利用静电纺丝技术制备了基于聚己内酯(PCL,polycaprolactone)的不同天然蛋白、多糖(丝素蛋白(SF,silk fibroin)、透明质酸(HA,hyaluronicacid))的混合组分纳米纤维,采用了扫描电镜和接触角对纳米纤维进行基础表征。同时,进一步考察了纳米纤维作为组织工程支架的可行性。研究结果表明SF组分能增加材料的可纺性,有利于细胞的前期黏附,并能够促进细胞增殖。HA组分可以改善材料的亲水性,增加细胞伪足并促进细胞迁移。重要的是,PCL/SF/HA纳米纤维能同时结合SF和HA的优点,有望在组织工程领域得到应用。     

Electrospinning of PLGA/gelatin randomly-oriented and aligned nanofibers as potential scaffold in tissue engineering

Electrospinning technique can be used to produce the three-dimensional nanofibrous scaffold similar to natural extracellular matrix, which satisfies particular requirements of tissue engineering scaffold. Randomly-oriented and aligned poly(lactic-co-glycolic acid) (PLGA) and PLGA/gelatin biocomposite scaffolds were successfully produced by electrospinning in the present study. The resulting nanofibrous scaffolds exhibited smooth surface and high porous structure. Blending PLGA with gelatin enhanced the hydrophilicity but decreased the average fiber diameter and the mechanical properties of the scaffolds under the same electrospinning condition. The cell culture results showed that the elongation of the osteoblast on the aligned nanofibrous scaffold was parallel to the fiber arrangement and the cell number was similar to that of randomly-oriented scaffold, indicating that the aligned nanofibrous scaffold provide a beneficial approach for the bone regeneration.     

Nanofibrous modification on ultra-thin poly(e-caprolactone) membrane via electrospinning

Poly(e-caprolactone) (PCL) is a favorable material for tissue engineering. PCL was successfully fabricated into less than 10 μm thin membranes using a 2-roll-heated-mill and biaxial stretching process. However, PCL is known for its poor cellular adhesion and surface modifications are needed for any tissue engineering applications. This paper reports on a novel surface modification technique of the PCL membrane by coating with electrospun nanofibers. The purpose was to mimic the architecture of the natural extracellular matrix and create nanotopography for enhanced cellular attachment. The surfaces were characterized by scanning electron microscopy (SEM), water contact angle and atomic force microscopy. The results showed that uniform nanofibrous topology were successfully achieved on the surface of the PCL membrane, with increased roughness (more than 17 times) and surface area. This nanofibrous topology induced capillary effects after sodium hydroxide (NaOH) treatment, causing the water contact angle to drop to almost zero. Scratch tests revealed a strong interaction of PCL nanofiber coating on the PCL membrane. AlamarBlue assay indicated that 3T3 fibroblast cells proliferated well on the nanofibrous membrane. Confocal Laser Scanning Microscope revealed better cell attachment onto the nanofibrous membranes than the untreated membranes. Results from SEM showed that the cells' spindle-shaped morphology on the NaOH-treated fibrous surface was evident while they remained in isolated spherical shaped entities in the non-treated fibrous surfaces.     

Poly(lactide-co-glycolide)/hydroxyapatite nanofibrous scaffolds fabricated by electrospinning for bone tissue engineering

Poly(lactide-co-glycolide) (PLGA) nanofibrous composite scaffolds having nano-hydroxyapatite particles (HAp) in the fibers were prepared by electrospinning of PLGA and HAp with an average diameter of 266.6 ± 7.3 nm. Microscopy and spectroscopy characterizations confirmed integration of the crystalline HAp in the scaffolds. Agglomerates gradually appeared and increased on the fiber surface along with increase of the HAp concentration. In vitro mineralization in a 5 × simulated body fluid (SBF) revealed that the PLGA/HAp nanofibrous scaffolds had a stronger biomineralization ability than the control PLGA scaffolds. Biological performance of the nanofibrous scaffolds of the control PLGA and PLGA with 5 wt% HAp (PLGA/5HAp) was assessed by in vitro culture of neonatal mouse calvaria-derived MC3T3-E1 osteoblasts. Both types of the scaffolds could support cell proliferation and showed sharp increase of viability until 7 days, but the cells cultured on the PLGA/5HAp nanofibers showed a more spreading morphology. Despite the similar level of the cell viability and cell number at each time interval, the alkaline phosphatase secretion was significantly enhanced on the PLGA/5HAp scaffolds, indicating the higher bioactivity of the as-prepared nano-HAp and the success of the present method for preparing biomimetic scaffold for bone regeneration.