Electrospinning of nano/micro scale poly(L-lactic acid) aligned fibers and their potential in neural tissue engineering

Efficacy of aligned poly(l-lactic acid) (PLLA) nano/micro fibrous scaffolds for neural tissue engineering is described and their performance with random PLLA scaffolds is compared as well in this study. Perfectly aligned PLLA fibrous scaffolds were fabricated by an electrospinning technique under optimum condition and the diameter of the electrospun fibers can easily be tailored by adjusting the concentration of polymer solution. As the structure of PLLA scaffold was intended for neural tissue engineering, its suitability was evaluated in vitro using neural stem cells (NSCs) as a model cell line. Cell morphology, differentiation and neurite outgrowth were studied by various microscopic techniques. The results show that the direction of NSC elongation and its neurite outgrowth is parallel to the direction of PLLA fibers for aligned scaffolds. No significant changes were observed on the cell orientation with respect to the fiber diameters. However, the rate of NSC differentiation was higher for PLLA nanofibers than that of micro fibers and it was independent of the fiber alignment. Based on the experimental results, the aligned nanofibrous PLLA scaffold could be used as a potential cell carrier in neural tissue engineering.     

Electrospun nanostructured scaffolds for bone tissue engineering

The current challenge in bone tissue engineering is to fabricate a bioartificial bone graft mimicking the extracellular matrix (ECM) with effective bone mineralization, resulting in the regeneration of fractured or diseased bones. Biocomposite polymeric nanofibers containing nanohydroxyapatite (HA) fabricated by electrospinning could be promising scaffolds for bone tissue engineering. Nanofibrous scaffolds of poly-l-lactide (PLLA, 860 ± 110 nm), PLLA/HA (845 ± 140 nm) and PLLA/collagen/HA (310 ± 125 nm) were fabricated, and the morphology, chemical and mechanical characterization of the nanofibers were evaluated using scanning electron microscopy, Fourier transform infrared spectroscopy and tensile testing, respectively. The in vitro biocompatibility of different nanofibrous scaffolds was also assessed by growing human fetal osteoblasts (hFOB), and investigating the proliferation, alkaline phosphatase activity (ALP) and mineralization of cells on different nanofibrous scaffolds. Osteoblasts were found to adhere and grow actively on PLLA/collagen/HA nanofibers with enhanced mineral deposition of 57% higher than the PLLA/HA nanofibers. The synergistic effect of the presence of an ECM protein, collagen and HA in PLLA/collagen/HA nanofibers provided cell recognition sites together with apatite for cell proliferation and osteoconduction necessary for mineralization and bone formation. The results of our study showed that the biocomposite PLLA/collagen/HA nanofibrous scaffold could be a potential substrate for the proliferation and mineralization of osteoblasts, enhancing bone regeneration.     

牙周膜细胞在网格型与无纺型聚乳酸纳米纤维支架材料上体外培养的研究比较

研究对比牙周膜细胞在无纺型和网格型聚乳酸纳米纤维膜上的生长行为,探讨支架结构对细胞生长的影响.采用静电纺丝技术,用金属平板或金属网分别接收,得到无纺型和网格型聚乳酸纳米纤维膜;通过SEM观察两种支架形貌差异,并测试比较它们的力学性能.通过MTT测试和SEM观察,比较无纺型和网格型纳米纤维膜对细胞生长的影响.实验结果:网格型膜的纤维直径平均为500～600 nm;无纺型膜的纤维直径大于网格型膜,平均直径约为700 nm,但网格型膜的拉伸断裂应变略大.牙周细胞与支架联合培养的MTT结果显示,与在聚苯乙烯(TCPS) 培养板上的培养比较,两种纳米纤维膜都显示出促进细胞增殖的效果,其中网格膜的促进效果比无纺膜更加明显.SEM观察的结果显示,细胞无法进入无纺型膜内部生长,而网格型膜中由疏松纤维堆积形成的大孔结构则非常有利于细胞进入支架内部,细胞在后者上生长良好.因此,网格型纳米纤维支架是一种优于纤维为完全无纺排布的支架,更适用于组织工程研究.     

An aligned nanofibrous collagen scaffold by electrospinning and its effects on in vitro fibroblast culture

Fabrication of nanofibrous scaffolds with well-defined architecture mimicking native extracellular matrix analog has significant potentials for many specific tissue engineering and organs regeneration applications. The fabrication of aligned collagen nanofibrous scaffolds by electrospinning was described in this study. The structure and in vitro properties of these scaffolds were compared with a random collagen scaffold. All the collagen scaffolds were first crosslinked in glutaraldehyde vapor to enhance the biostability and keep the initial nano-scale dimension intact. From in vitro culture of rabbit conjunctiva fibroblast, the aligned scaffold exhibited lower cell adhesion but higher cell proliferation because of the aligned orientation of fibers when compared with the random scaffold. And the alignment of the fibers may control cell orientation and strengthen the interaction between the cell body and the fibers in the longitudinal direction of the fibers.     

Nanostructured biocomposite substrates by electrospinning and electrospraying for the mineralization of osteoblasts

Nanotechnology has enabled the engineering of nanostructured materials to meet current challenges in bone replacement therapies. Biocomposite nanofibrous scaffolds of poly(l-lactic acid)-co-poly(?-caprolactone), gelatin and hydroxyapatite (HA) were fabricated by combining the electrospinning and electrospraying techniques in order to create a better osteophilic environment for the growth and mineralization of osteoblasts. Electrospraying of HA nanoparticles on electrospun nanofibers helped to attain rough surface morphology ideal for cell attachment and proliferation and also achieve improved mechanical properties than HA blended nanofibers. Nanofibrous scaffolds showed high pore size and porosity up to 90% with fiber diameter in the range of 200–700 nm. Nanofibrous scaffolds were characterized for their functional groups and chemical structure by FTIR and XRD analysis. Studies on cell–scaffold interaction were carried out by culturing human fetal osteoblast cells (hFOB) on both HA blended and sprayed PLACL/Gel scaffolds and assessing their growth, proliferation, mineralization and enzyme activity. The results of MTS, ALP, SEM and ARS studies confirmed, not only did HA sprayed biocomposite scaffolds showed better cell proliferation but also enhanced mineralization and alkaline phosphatase activity (ALP) proving that electrospraying in combination with electrospinning produced superior and more suitable biocomposite nanofibrous scaffolds for bone tissue regeneration.     

The effect of poly (L-lactic acid) nanofiber orientation on osteogenic responses of human osteoblast-like MG63 cells

In this study, poly (L-lactic acid) (PLLA)/trifluoroethanol (TFE) solution was electrospun to fabricate fibrous scaffolds with different fiber orientations. Random and parallel PLLA nanofiber alignments were achieved by using a metal plate and a rolling rod as the receiver, respectively. The parallel PLLA fibrous scaffolds were further hot-stretched to obtain hyperparallel PLLA fibrous scaffolds. The PLLA fibrous scaffolds were characterized by fiber diameter, interfiber distance, fiber array angle, water contact angle, morphology and mechanical strength. The tensile strength of hyperparallel nano-fibers was approximately 5- and 14-times the parallel and random fibers, respectively. Osteoblast-like MG63 cells were cultured on the PLLA scaffolds to study the effects of fiber orientation on cell morphology, proliferation and differentiation. The cells on the randomly-oriented scaffolds showed irregular forms, while the cells exhibited shuttle-like shapes on the parallel scaffolds and had larger aspect ratios along the fiber direction of the hyperparallel scaffolds. Alkaline phosphatase (ALP) activity and collagen I (placeStateCol I) and osteocalcin (OC) deposition exhibited fiber orientation dependence. With an increase in parallelism of the fibers, there was a decrease in ALP activity and placeStateCol I and OC production. These results suggest that exploitation of PLLA fiber orientation may be used to control osteoblast-like cell responses.     

Electrospun Biomimic Nanofibrous Scaffolds of Silk Fibroin/Hyaluronic Acid for Tissue Engineering

Abstract

This study aimed to fabricate nanofibrous scaffolds which could biomimic the natural extracellular matrix from aqueous solutions of silk fibroin and hyaluronic acid blends (SF/HA) by means of electrospinning. Scanning electronic microscopy results indicated that electrospun SF/HA nanofibers were ribbon-shaped and their average width obviously decreased with the increase of HA content. However, there is no fiber observed when the volume of HA further increased to 50% of overall volume. After being treated with 75% ethanol vapor for 24 h, the fibers still remained their fibrous morphologies and presented good capability of water-resistance. Fourier transform infrared attenuated total reflectance spectroscopy, ¹³C-CP-MAS nuclear magnetic resonance and differential scanning calorimetry results revealed that HA did not induce SF conformation from random coil to β-sheet. SF conformation converted from random coil to β-sheet after being treated with 75% ethanol vapor. Cell viability studies demonstrated that SF/HA nanofibrous scaffolds significantly promoted cell proliferation. Electrospun SF/HA nanofibers may provide an ideal biomimic tissue-engineering scaffold or vehicle for water-soluble drugs.     

聚左旋乳酸/壳聚糖电纺丝纳米纤维支架与兔内皮祖细胞的生物相容性

背景：电纺丝技术能够使许多高分子材料制备出与细胞外基质相似的三维纳米纤维支架。聚乳酸/壳聚糖纳米纤维复合支架材料能够克服材料的不足,提高组织工程支架生物相容性。 目的：评价聚左旋乳酸/壳聚糖电纺丝纳米纤维支架与兔内皮祖细胞的生物相容性。 方法：电纺丝技术制备聚左旋乳酸,壳聚糖,聚左旋乳酸/壳聚糖的纳米纤维支架,扫描电镜观察其形貌结构。纳米纤维支架与内皮祖细胞进行复合培养后,观察细胞在不同材料上的黏附率、一氧化氮分泌,生长特征和在聚左旋乳酸/壳聚糖纳米纤维支架上的细胞表型特征。 结果与结论：聚左旋乳酸/壳聚糖纳米纤维支架比聚左旋乳酸、壳聚糖具有更合适的纤维直径,具有与细胞外基质相似的纳米纤维三维多孔结构。聚左旋乳酸/壳聚糖纳米纤维支架能够促进内皮祖细胞黏附率和细胞的一氧化氮分泌(P < 0.05,P < 0.01)。内皮祖细胞能够在聚左旋乳酸/壳聚糖复合材料膜上融合成片,保持了细胞的完整形态和分化功能,显示了内皮细胞特异性的vWF表型。提示聚左旋乳酸/壳聚糖电纺丝纳米纤维支架与兔内皮祖细胞具有良好的生物相容性。     

Characterization of neural stem cells on electrospun poly(L-lactic acid) nanofibrous scaffold

Nanofibrous poly(L-lactic acid) (PLLA) scaffolds were fabricated by an electrospinning technique and characterized by scanning electron microscopy, mercury porosimeter, atomic force microscopy and contact-angle test. The produced PLLA fibers with diameters ranging from 150 to 350 nm were randomly orientated with interconnected pores varying from several microm to about 140 microm in-between to form a three-dimensional architecture, which resembles the natural extracellular matrix structure in human body. The in vitro cell culture study was performed and the results indicate that the nanofibrous scaffold not only supports neural stem cell (NSC) differentiation and neurites out-growth, but also promotes NSC adhesion. The favorable interaction between the NSCs and the nanofibrous scaffold may be due to the greatly improved surface roughness of the electrospun nanofibrous scaffold. As evidenced by this study, the electrospun nanofibrous scaffold is expected to play a significant role in neural tissue engineering.     

Characterization of neural stem cells on electrospun poly(L-lactic acid) nanofibrous scaffold

Nanofibrous poly(L-lactic acid) (PLLA) scaffolds were fabricated by an electrospinning technique and characterized by scanning electron microscopy, mercury porosimeter, atomic force microscopy and contact-angle test. The produced PLLA fibers with diameters ranging from 150 to 350 nm were randomly orientated with interconnected pores varying from several μm to about 140 μm in-between to form a three-dimensional architecture, which resembles the natural extracellular matrix structure in human body. The in vitro cell culture study was performed and the results indicate that the nanofibrous scaffold not only supports neural stem cell (NSC) differentiation and neurites out-growth, but also promotes NSC adhesion. The favorable interaction between the NSCs and the nanofibrous scaffold may be due to the greatly improved surface roughness of the electrospun nanofibrous scaffold. As evidenced by this study, the electrospun nanofibrous scaffold is expected to play a significant role in neural tissue engineering.     

The engineering of patient-specific,anatomically shaped,digits

It is now recognized that geometric structures of scaffolds at several size levels have profound influences on cell adhesion, viability, proliferation and differentiation. This study aims to develop an integrated process to fabricate scaffolds with controllable geometric structures at nano-, micro- and macro-scales. A phase-separation method is used to prepare interconnected poly(l-lactide) (PLLA) nanofibrous (NF) scaffolds. The pore size of the NF scaffold at the scale of several hundred micrometers is controlled by the size of porogen, paraffin spheres. At millimeter scale and above, the overall shape of the scaffold is defined by a wax mold produced using a three-dimensional printer. The printer utilizes a stereo lithographic file generated from computed tomographic files retrieved from the National Library of Medicine's Visual Human Project. NF PLLA scaffolds with a human digit shape are successfully prepared using this process. Osteoblast cell line MC3T3-E1 cells are then seeded and cultured in the prepared scaffolds. Cell proliferation, differentiation and biomineralization are characterized to demonstrate the suitability of the scaffolds for the digit bone tissue engineering application.     

Simultaneous electrospin–electrosprayed biocomposite nanofibrous scaffolds for bone tissue regeneration

Currently, the application of nanotechnology in bone tissue regeneration is a challenge for the fabrication of novel bioartificial bone grafts. These nanostructures are capable of mimicking natural extracellular matrix with effective mineralization for successful regeneration of damaged tissues. The simultaneous electrospraying of nanohydroxyapatite (HA) on electrospun polymeric nanofibrous scaffolds might be more promising for bone tissue regeneration. In the current study, nanofibrous scaffolds of gelatin (Gel), Gel/HA (4:1 blend), Gel/HA (2:1 blend) and Gel/HA (electrospin–electrospray) were fabricated for this purpose. The morphology, chemical and mechanical stability of nanofibres were evaluated by means of field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy and with a universal tensile machine, respectively. The in vitro biocompatibility of different nanofibrous scaffolds was determined by culturing human foetal osteoblasts and investigating the proliferation, alkaline phosphatase (ALP) activity and mineralization of cells. The results of cell proliferation, ALP activity and FESEM studies revealed that the combination of electrospinning of gelatin and electrospraying of HA yielded biocomposite nanofibrous scaffolds with enhanced performances in terms of better cell proliferation, increased ALP activity and enhanced mineralization, making them potential substrates for bone tissue regeneration.     

Uniformly-aligned gelatin/polycaprolactone fibers promote proliferation in adipose-derived stem cells and have distinct effects on cardiac cell differentiation

Cardiac tissue engineering is a promising technique to regenerate cardiac tissue and treat cardiovascular disease. Here we applied a modified method to generate ultrafine uniformly-aligned composite gelatin/polycaprolactone fibers that mimic functional heart tissue. We tested the physical properties of these fibers and analyzed how these composite fibrous scaffolds affected growth and cardiac lineage differentiation in rat adipose-derived stem cells (rADSCs). We found that uniformly aligned composite fiber scaffolds had an anisotropic arrangement, functional mechanical properties, and strong hydrophilicity. The anisotropic scaffolds improved cell attachment, viability, and proliferative capacity of ADSCs over randomly-aligned scaffolds. Furthermore, uniformly aligned composite fiber scaffolds increased the efficiency of cardiomyogenic differentiation, but might reduce the efficiency of cardiac conduction system cell differentiation in ADSCs compared to randomly-oriented scaffolds and tissue culture polystyrene. However, the randomly-oriented composite scaffolds showed no obviously facilitated effects over tissue culture polystyrene on the two cells’ differentiation process. The above results indicate that the scaffold fiber alignment has a greater effect on cell differentiation than the composition of the scaffold. Together, the uniformly-aligned composite fibers displayed excellent physical and biocompatible properties, promoted ADSC proliferation, and played distinct roles in the differentiation of cardiomyogenic cells and cardiac conduction system cells from ADSCs. These results provide new insight for the application of anisotropic fibrous scaffolds in cardiac tissue engineering for both in vitro and in vivo research.     

Beneficial effect of aligned nanofiber scaffolds with electrical conductivity for the directional guide of cells

Abstract

Conducting polymer-based scaffolds receive biological and electrical signals from the extracellular matrix (ECM) or peripheral cells, thereby promoting cell growth and differentiation. Chitin, a natural polymer, is widely used as a scaffold because it is biocompatible, biodegradable, and nontoxic. In this study, we used an electrospinning technique to fabricate conductive scaffolds from aligned chitin/polyaniline (Chi/PANi) nanofibers for the directional guidance of cells. Pure chitin and random and aligned Chi/PANi nanofiber scaffolds were characterized using field emission scanning electron microscope (FE-SEM) and by assessing wettability, mechanical properties, and electrical conductivity. The diameters of aligned Chi/PANi nanofibers were confirmed to be smaller than those of pure chitin and random nanofibers owing to electrostatic forces and stretching produced by rotational forces of the drum collector. The electrical conductivity of aligned Chi/PANi nanofiber scaffolds was ~91% higher than that of random nanofibers. We also studied the viability of human dermal fibroblasts (HDFs) cultured on Chi/PANi nanofiber scaffolds in vitro using a CCK-8 assay, and found that cell viability on the aligned Chi/PANi nanofiber scaffolds was ~2.1-fold higher than that on random Chi/PANi nanofiber scaffolds after 7 days of culture. Moreover, cells on aligned nanofiber scaffolds spread in the direction of the aligned nanofibers (bipolar), whereas cells on the random nanofibers showed no spreading (6 h of culture) or multipolar patterns (7 days of culture). These results suggest that aligned Chi/PANi nanofiber scaffolds with conductivity exert effects that could improve survival and proliferation of cells with directionality.     

Electrospun Poly(L-Lactic Acid) Nanofibres Loaded with Dexamethasone to Induce Osteogenic Differentiation of Human Mesenchymal Stem Cells

Abstract

Dexamethasone (Dex), a synthetic corticosteroid, was loaded into poly(L-lactic acid) (PLLA) nanofibrous scaffolds with a concentration of 0.333 wt% by electrospinning. The Dex-loaded PLLA nanofibres increased the mechanical strength in comparison with pure PLLA nanofibres. A sustained release profile for over 2 months with an initial burst release after 12 h of 17% was shown. Importantly, the amounts of Dex released from the PLLA nanofibres every 3 days were close to the ones used for the standard osteogenic medium. The sustained osteoinductive environment created by released Dex strongly differentiated human mesenchymal stem cells (hMSCs) cultured in the Ost^–Dex medium. ALP activity, BSP expression and calcium deposition were significantly higher than those of the cells cultured on the PLLA scaffolds without Dex. A large amount of hydroxyapatite-like minerals was observed on the Dex-loaded PLLA scaffolds after 21 days culture. The cells on these scaffolds also indicated an osteoblastic morphology on the 14th day. Besides, these scaffolds slightly increased the cell proliferation comparing to the scaffolds without Dex. As such, the PLLA nanofibres loaded with 0.333 wt% Dex was an effective osteoinductive scaffold which acts as a promising strategy for bone treatment.     

天冬氨酸修饰纳米羟基磷灰石/聚乳酸复合物制备软骨组织工程支架及其生物性能研究

目的:通过天冬氨酸修饰的纳米羟基磷灰石（Asp-nHA）和左旋聚乳酸（PLLA）复合,制备软骨组织工程支架,并进行体外实验研究,探索其作为软骨组织工程支架的可行性。 方法:以碳二亚胺盐酸盐/N-羟基琥珀酰亚胺偶联法制备Asp-nHA,并与PLLA复合,获得新型Asp-nHA/PLLA纳米复合支架。比较成骨细胞在该新型材料表面的粘附、生长和增殖的情况。 结果:加入nHA后,Asp-nHA/PLLA复合材料可显著增强细胞的粘附、生长、增殖;Asp-nHA/PLLA的生物学性能明显优于PLLA及HA/PLLA,且Asp-nHA/PLLA具有最强的体外诱导成骨细胞分化能力。 结论:Asp-nHA/PLLA制备简单,具有良好的生物相容性和成骨活性,是一种性能良好的骨组织工程支架材料。     

Preparation and characterization of bionic bone structure chitosan/hydroxyapatite scaffold for bone tissue engineering

Three-dimensional oriented chitosan (CS)/hydroxyapatite (HA) scaffolds were prepared via in situ precipitation method in this research. Scanning electron microscopy (SEM) images indicated that the scaffolds with acicular nano-HA had the spoke-like, multilayer and porous structure. The SEM of osteoblasts which were polygonal or spindle-shaped on the composite scaffolds after seven-day cell culture showed that the cells grew, adhered, and spread well. The results of X-ray powder diffractometer and Fourier transform infrared spectrometer showed that the mineral particles deposited in the scaffold had phase structure similar to natural bone and confirmed that particles were exactly HA. In vitro biocompatibility evaluation indicated the composite scaffolds showed a higher degree of proliferation of MC3T3-E1 cell compared with the pure CS scaffolds and the CS/HA10 scaffold was the highest one. The CS/HA scaffold also had a higher ratio of adhesion and alkaline phosphate activity value of osteoblasts compared with the pure CS scaffold, and the ratio increased with the increase of HA content. The ALP activity value of composite scaffolds was at least six times of the pure CS scaffolds. The results suggested that the composite scaffolds possessed good biocompatibility. The compressive strength of CS/HA15 increased by 33.07% compared with the pure CS scaffold. This novel porous scaffold with three-dimensional oriented structure might have a potential application in bone tissue engineering.     

Biocompatibility evaluation of emulsion electrospun nanofibers using osteoblasts for bone tissue engineering

Emulsion electrospinning is an advanced technique to fabricate core-shell structured nanofibrous scaffolds, with great potential for drug encapsulation. Incorporation of dual factors hydroxyapatite (HA) and laminin, respectively, within the shell and core of nanofibers through emulsion electrospinning might be of advantageous in supporting the adhesion, proliferation, and maturation of cells instead of single factor-encapsulated nanofibers. We fabricated poly(L-lactic acid-co-?-caprolactone) (PLCL)/hydroxyapaptite (PLCL/HA), PLCL/laminin (PLCL/Lam), and PLCL/hydroxyapatite/laminin (PLCL/HA/Lam) scaffolds with fiber diameter of 388?±?35, 388?±?81, and 379?±?57?nm, respectively, by emulsion electrospinning. The elastic modulus of the prepared scaffolds ranged from 22.7–37.0?MPa. The osteoblast proliferation on PLCL/HA/Lam scaffolds, determined on day 21, was found 10.4% and 12.0% higher than the cell proliferation on PLCL/Lam or PLCL/HA scaffold, respectively. Cell maturation determined on day 14, by alkaline phosphatase (ALP) activity, was significantly higher on PLCL/HA/Lam scaffolds than the ALP activity on PLCL/HA and PLCL/Lam scaffolds (p???0.05). Results of the energy dispersive X-ray studies carried out on day 28 also showed higher calcium deposition by cells seeded on PLCL/HA/Lam scaffolds. Osteoblasts were found to adhere, proliferate, and mature actively on PLCL/HA/Lam nanofibers with enhanced cell proliferation, ALP activity, bone protein expression, and mineral deposition. Based on the results, we can conclude that laminin and HA individually played roles in osteoblast proliferation and maturation, and the synergistic function of both factors within the novel emulsion electrospun PLCL/HA/Lam nanofibers enhanced the functionality of osteoblasts, confirming their potential application in bone tissue regeneration.     

Improvement of dual-leached polycaprolactone porous scaffolds by incorporating with hydroxyapatite for bone tissue regeneration

Polycaprolactone (PCL)/hydroxyapatite (HA) composite scaffolds were prepared by combining solvent casting and salt particulate leaching with a polymer leaching technique. The hydrophilicity of the dual-leached scaffold was improved by alkaline (NaOH) treatment. Well-defined interconnected pores were detected by scanning electron microscopy. The water absorption capacity of the NaOH-treated PCL/HA dual-leached scaffold increased greatly, confirming that the hydrophilicity of the scaffold was improved by NaOH treatment. The compressive modulus of the PCL/HA dual-leached scaffold was greatly increased by the addition of HA particles. An indirect evaluation of the cytotoxicity of all PCL dual-leached scaffolds with mouse fibroblastic cells (L929) and mouse calvaria-derived pre-osteoblastic cells (MC3T3-E1) indicated that the PCL dual-leached scaffolds are non-toxic to cells. The ability of the scaffolds to support mouse calvaria-derived pre-osteoblastic cell (MC3T3-E1) attachment, proliferation, differentiation, and mineralization was also evaluated. Although the viability of cells was lower on the PCL/HA dual-leached scaffold than on the tissue-culture polystyrene plates (TCPS) and on the other substrates at early time points, both the PCL and NaOH-treated PCL/HA dual-leached scaffolds supported the attachment of MC3T3-E1 at significantly higher levels than TCPS. During the proliferation period (days 1–3), all of the PCL dual-leached scaffolds were able to support the proliferation of MC3T3-E1 at higher levels than the TCPS; in addition, the cells grown on NaOH-treated PCL/HA dual-leached scaffolds proliferated more rapidly. The cells cultured on the surfaces of NaOH-treated PCL/HA dual-leached scaffolds had the highest rate of mineral deposition.     

Synergistic effects of electrospun PLLA fiber dimension and pattern on neonatal mouse cerebellum C17.2 stem cells

Topographical features, including fiber dimensions and pattern, are important aspects in developing fibrous scaffolds for tissue engineering. In this study aligned poly(l-lactide) (PLLA) fibers with diameters of 307 ± 47, 500 ± 53, 679 ± 72 and 917 ± 84 nm and random fibers with diameters of 327 ± 40, 545 ± 54, 746 ± 82 and 1150 ± 109 nm were obtained by optimizing the electrospinning parameters. We cultured neonatal mouse cerebellum C17.2 cells on the PLLA fibers. These neural stem cells (NSCs) exhibited significantly different growth and differentiation depending upon fiber dimension and pattern. On aligned fibers cell viability and proliferation was best on 500 nm fibers, and reduced on smaller or larger fibers. However, on random fibers cell viability and proliferation was best with the smallest (350 nm) and largest (1150 nm) diameter fibers. Polarized and elongated cells were orientated along the fiber direction on the aligned fibers, with focal contacts bridging the cell body and aligned fibers. Cells of spindle and polygonal morphologies were randomly distributed on the random fibers, with no focal contacts observed. Moreover, longer neurites were obtained on the aligned fibers than random fibers within the same diameter range. Thus, the surface topographic morphologies of fibrous scaffolds, including fiber pattern, dimensions and mesh size, play roles in regulating the viability, proliferation and neurite outgrowth of NSCs. Nevertheless, our results indicated that aligned 500 nm fiber are most promising for fine tuning the design of a nerve scaffold.