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.     

Electrospun chitosan/hydroxyapatite nanofibers for bone tissue engineering

Chitosan (CS) nanofibers were prepared by an electrospinning technique and then treated with simulated body fluid (SBF) to encourage hydroxyapatite (HA) formation on their surface. The CS/HA nanofibers were subjected to scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy, and X-ray diffraction (XRD) to confirm HA formation as well as determine the morphology of the nanofibrous scaffolds. The SEM image indicated that the distribution of HA on the CS nanofibers was homogeneous. The results from EDS and XRD indicated that HA was formed on the nanofibrous surfaces after 6-day incubation in the SBF. The calcium/phosphorus ratio of deposited HA was close to that of natural bone. To determine biocompatibility, the CS/HA scaffolds were applied to the culture of rat osteosarcoma cell lines (UMR-106). The cell densities on the CS/HA nanofibers were higher than those on the CS nanofibers, the CS/HA film, and the CS film, indicating that cell proliferation on CS/HA nanofibers was enhanced. Moreover, the early osteogenic differentiation on CS/HA was also more significant, due to the differences in chemical composition and the surface area of CS/HA nanofibers. The biocompatibility and the cell affinity were enhanced using the CS/HA nanofibers. This indicates that electrospun CS/HA scaffolds would be a potential material in bone tissue engineering.     

New approach to bone tissue engineering: simultaneous application of hydroxyapatite and bioactive glass coated on a poly(L-lactic acid) scaffold

A combination of bioceramics and polymeric nanofibers holds promising potential for bone tissue engineering applications. In the present study, hydroxyapatite (HA), bioactive glass (BG), and tricalcium phosphate (TCP) particles were coated on the surface of electrospun poly(L-lactic acid) (PLLA) nanofibers, and the capacity of the PLLA, BG-PLLA, HA-PLLA, HA-BG-PLLA, and TCP-PLLA scaffolds for bone regeneration was investigated in rat critical-size defects using digital mammography, multislice spiral-computed tomography (MSCT) imaging, and histological analysis. Electrospun scaffolds exhibited a nanofibrous structure with a homogeneous distribution of bioceramics along the surface of PLLA nanofibers. A total of 8 weeks after implantation, no sign of complication or inflammation was observed at the site of the calvarial bone defect. On the basis of imaging analysis, a higher level of bone reconstruction was observed in the animals receiving HA-, BG-, and TCP-coated scaffolds compared to an untreated control group. In addition, simultaneous coating of HA and BG induced the highest regeneration among all groups. Histological staining confirmed these findings and also showed an efficient osseointegration in HA-BG-coated nanofibers. On the whole, it was demonstrated that nanofibrous structures could serve as an appropriate support to guide the healing process, and coating their surface with bioceramics enhanced bone reconstruction. These bioceramic-coated scaffolds can be used as new bone-graft substitutes capable of efficiently inducing osteoconduction and osseointegration in orthopedic fractures and defects.     

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.     

左旋聚乳酸/多壁碳纳米管/羟基磷灰石电纺丝纳米纤维的形态及生物降解性能

采用静电纺丝法制备了左旋聚乳酸/多壁碳纳米管/羟基磷灰石(PLLA/MW NT s/HA)杂化纳米纤维无纺毡,分析了MW NT s的加入对杂化纤维形态结构的影响,以及不同工艺条件下纤维的直径分布,并研究了纤维无纺毡在磷酸盐缓冲溶液(pH 7.4,37℃)中的体外降解过程。结果表明:MW NT s的加入使PLLA/HA纤维直径略有减小;PLLA/MW NT s/HA杂化纤维体系降解液的pH值下降到一定程度后,在降解后期呈缓慢上升趋势;碱性MW NT s/HA的加入抑制了PLLA降解过程中的自催化作用,减缓了PLLA的降解速度。     

Development of a novel collagen–GAG nanofibrous scaffold via electrospinning

Collagen and glycosaminoglycan (GAG) are native constituents of human tissues and are widely utilized to fabricate scaffolds serving as an analog of native extracellular matrix (ECM).The development of blended collagen and GAG scaffolds may potentially be used in many soft tissue engineering applications since the scaffolds mimic the structure and biological function of native ECM. In this study, we were able to obtain a novel nanofibrous collagen–GAG scaffold by electrospinning with collagen and chondroitin sulfate (CS), a widely used GAG. The electrospun collagen–GAG scaffold exhibited a uniform fiber structure in nano-scale diameter. By crosslinking with glutaraldehyde vapor, the collagen–GAG scaffolds could resist from collagenase degradation and enhance the biostability of the scaffolds. This led to the increased proliferation of rabbit conjunctiva fibroblast on the scaffolds. Incorporation of CS into collagen nanofibers without crosslinking did not increase the biostability but still promoted cell growth. In conclusion, the electrospun collagen–GAG scaffolds, with high surface-to-volume ratio, may potentially provide a better environment for tissue formation/biosynthesis compared with the traditional scaffolds.     

Polysaccharide nanofibrous scaffolds as a model for in vitro skin tissue regeneration

Tissue engineering and nanotechnology have advanced a general strategy combining the cellular elements of living tissue with sophisticated functional biocomposites to produce living structures of sufficient size and function at a low cost for clinical relevance. Xylan, a natural polysaccharide was electrospun along with polyvinyl alcohol (PVA) to produce Xylan/PVA nanofibers for skin tissue engineering. The Xylan/PVA glutaraldehyde (Glu) vapor cross-linked nanofibers were characterized by SEM, FT-IR, tensile testing and water contact angle measurements to analyze the morphology, functional groups, mechanical properties and wettability of the fibers for skin tissue regeneration. The cell-biomaterial interactions were studied by culturing human foreskin fibroblasts on Xylan/PVA Glu vapor cross-linked and Xylan/PVA/Glu blend nanofibrous scaffolds. The observed results showed that the mechanical properties (72 %) and fibroblast proliferation significantly increased up to 23 % (P < 0.05) in 48 h Glu vapor cross-linked nanofibers compared to 24 h Glu vapor cross-linked Xylan/PVA nanofibers. The present study may prove that the natural biodegradable Xylan/PVA nanofibrous scaffolds have good potential for fibroblast adhesion, proliferation and cell matrix interactions relevant for skin tissue regeneration.     

Fabrication of mineralized electrospun PLGA and PLGA/gelatin nanofibers and their potential in bone tissue engineering

Surface mineralization is an effective method to produce calcium phosphate apatite coating on the surface of bone tissue scaffold which could create an osteophilic environment similar to the natural extracellular matrix for bone cells. In this study, we prepared mineralized poly(d,l-lactide-co-glycolide) (PLGA) and PLGA/gelatin electrospun nanofibers via depositing calcium phosphate apatite coating on the surface of these nanofibers to fabricate bone tissue engineering scaffolds by concentrated simulated body fluid method, supersaturated calcification solution method and alternate soaking method. The apatite products were characterized by the scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD) methods. A large amount of calcium phosphate apatite composed of dicalcium phosphate dihydrate (DCPD), hydroxyapatite (HA) and octacalcium phosphate (OCP) was deposited on the surface of resulting nanofibers in short times via three mineralizing methods. A larger amount of calcium phosphate was deposited on the surface of PLGA/gelatin nanofibers rather than PLGA nanofibers because gelatin acted as nucleation center for the formation of calcium phosphate. The cell culture experiments revealed that the difference of morphology and components of calcium phosphate apatite did not show much influence on the cell adhesion, proliferation and activity.     

Investigation of cancer cell behavior on nanofibrous scaffolds

Tissue engineering and the use of nanofibrous biomaterial scaffolds offer a unique perspective for studying cancer development in vitro. Current in vitro models of tumorigenesis are limited by the use of static, two-dimensional (2D) cell culture monolayers that lack the structural architecture necessary for cell-cell interaction and three-dimensional (3D) scaffolds that are too simplistic for studying basic pathological mechanisms. In this study, two nanofibrous biomaterials that mimic the structure of the extracellular matrix, bacterial cellulose and electrospun polycaprolactone (PCL)/collagen I, were investigated as potential 3D scaffolds for an in vitro cancer model. Multiple cancer cell lines were cultured on each scaffold material and monitored for cell viability, proliferation, adhesion, infiltration, and morphology. Both bacterial cellulose and electrospun PCL/collagen I, which have nano-scale structures on the order of 100-500 nm, have been used in many diverse tissue engineering applications. Cancer cell adhesion and growth were limited on bacterial cellulose, while all cellular processes were enhanced on the electrospun scaffolds. This initial analysis has demonstrated the potential of electrospun PCL/collagen I scaffolds toward the development of an improved 3D in vitro cancer model.     

Electrospinning collagen and hyaluronic acid nanofiber meshes

Collagen and hyaluronic acid (HA) are main components of the extracellular matrix and have been utilized in electrospinning; a technique that creates nanosized fibers for tissue scaffolds. A collagen/HA polymer solution was electrospun into a scaffold material for osteoporosis patients who have reduced bone strength. To synthesize nanofibers, a high voltage was applied to the polymer solution to draw out nanofibers that were collected on a ground plate as a uniform mesh. The meshes were then crosslinked to render them insoluble and conjugated with gold nanoparticles to promote biocompatibility. Characterization of the mesh was performed using scanning electron microscope, electron dispersive spectroscopy and fourier transform infrared spectroscopy. A WST-1 assay determined the potential biocompatibility. The results show that collagen/HA scaffolds were developed that were insoluble in aqueous solutions and promoted cellular attachment that could be used as a tissue engineered scaffold to promote cell growth.     

A novel electrospun silk fibroin/hydroxyapatite hybrid nanofibers

A novel electrospinning of silk fibroin/hydroxyapatite hybrid nanofibers with different composition ratios was performed with methanoic acid as a spinning solvent. The silk fibroin/hydroxyapatite hybrids containing up to 30% hydroxyapatite nanoparticles could be electrospun into the continuous fibrous structure. The electrospun silk fibroin/hydroxyapatite hybrid nanofibers showed bigger diameter and wider diameter distribution than pure silk fibroin nanofibers, and the average diameter gradually increased from 95 to 582 nm. At the same time, the secondary structure of silk fibroin/hydroxyapatite nanofibers was characterized by X-ray diffraction, Fourier transform infrared analysis, and DSC measurement. Comparing with the pure silk fibroin nanofibers, the crystal structure of silk fibroin was mainly amorphous structure in the hybrid nanofibers. X-ray diffraction results demonstrated the hydroxyapatite crystalline nature remained as evidenced from the diffraction planes (002), (211), (300), and (202) of the hydroxyapatite crystallites, which was also confirmed by Fourier transform infrared analysis. The thermal behavior of hybrid nanofibers exhibited the endothermic peak of moisture evaporation ranging from 86 to 113 °C, and the degradation peak at 286 °C appeared. The SF/HAp nanofibers mats containing 30% HAp nanoparticles showed higher breaking tenacity and extension at break for 1.1688 ± 0.0398 MPa and 6.55 ± 1.95%, respectively. Therefore, the electrospun silk fibroin/hydroxyapatite hybrid nanofibers should be provided potentially useful options for the fabrication of biomaterial scaffolds for bone tissue engineering.     

Electrospun polyvinyl alcohol-collagen-hydroxyapatite nanofibers: a biomimetic extracellular matrix for osteoblastic cells

The failure of prosthesis after total joint replacement is due to the lack of early implant osseointegration. In this study polyvinyl alcohol-collagen-hydroxyapatite (PVA-Col-HA) electrospun nanofibrous meshes were fabricated as a biomimetic bone-like extracellular matrix for the modification of orthopedic prosthetic surfaces. In order to reinforce the PVA nanofibers, HA nanorods and Type I collagen were incorporated into the nanofibers. We investigated the morphology, biodegradability, mechanical properties and biocompatibility of the prepared nanofibers. Our results showed these inorganic-organic blended nanofibers to be degradable in vitro. The encapsulated nano-HA and collagen interacted with the PVA content, reinforcing the hydrolytic resistance and mechanical properties of nanofibers that provided longer lasting stability. The encapsulated nano-HA and collagen also enhanced the adhesion and proliferation of murine bone cells (MC3T3) in vitro. We propose the PVA-Col-HA nanofibers might be promising modifying materials on implant surfaces for orthopedic applications.     

Novel biomimetic hydroxyapatite/alginate nanocomposite fibrous scaffolds for bone tissue regeneration

Hydroxyapatite/alginate nanocomposite fibrous scaffolds were fabricated via electrospinning and a novel in situ synthesis of hydroxyapatite (HAp) that mimics mineralized collagen fibrils in bone tissue. Poorly crystalline HAp nanocrystals, as confirmed by X-ray diffractometer peak approximately at 2θ = 32° and Fourier transform infrared spectroscopy spectrum with double split bands of PO₄(v ₄) at 564 and 602 cm^?1, were induced to nucleate and grow at the [–COO^?]–Ca²⁺–[–COO^?] linkage sites on electrospun alginate nanofibers impregnated with PO₄ ^3? ions. This novel process resulted in a uniform deposition of HAp nanocrystals on the nanofibers, overcoming the severe agglomeration of HAp nanoparticles processed by the conventional mechanical blending/electrospinning method. Preliminary in vitro cell study showed that rat calvarial osteoblasts attached more stably on the surface of the HAp/alginate scaffolds than on the pure alginate scaffold. In general, the osteoblasts were stretched and elongated into a spindle-shape on the HAp/alginate scaffolds, whereas the cells had a round-shaped morphology on the alginate scaffold. The unique nanofibrous topography combined with the hybridization of HAp and alginate can be advantageous in bone tissue regenerative medicine applications.     

Electrospun fibrous web of collagen–apatite precipitated nanocomposite for bone regeneration

Electrospinning is regarded as a facile tool to generate biomaterials into a nanofibrous structure. Herein a nanofibrous web constituted of collagen and hydroxyapatite (HA) was produced from their co-precipitated nanocomposite solution by using the electrospinning method. The co-precipitated sol was freeze-dried and the dried product was dissolved in an organic solvent for the electrospinning. The electrospun web showed a well-developed nanofibrous structure with HA contents of up to 20 wt%. The internal structure of the collagen-20 wt%HA nanofiber revealed highly elongated apatite nanocrystallines precipitated within the collagen matrix. However, above the HA content of 30 wt% the nanofibrous structure could not be preserved due to the formation of beads. The MC3T3-E1 osteoblastic cells were shown to adhere and grow actively on the collagen-HA nanofibrous web. The alkaline phosphatase (ALP) activity expressed by the cells on the collagen-20 wt%HA nanofiber was lower at day 7, but was higher at day 14 than that on the pure collagen nanofiber. Based on the study, the newly-developed collagen-HA nanofiber may be useful as a cell supporting substrate in bone regeneration area.     

Composite poly-l-lactic acid/poly-(α,β)-dl-aspartic acid/collagen nanofibrous scaffolds for dermal tissue regeneration

Tissue engineering scaffolds for skin tissue regeneration is an ever expounding area of research, as the products that meet the necessary requirements are far and elite. The nanofibrous poly-l-lactic acid/poly-(α,β)-dl-aspartic acid/Collagen (PLLA/PAA/Col I&III) scaffolds were fabricated by electrospinning and characterized by SEM, contact angle and FTIR analysis for skin tissue regeneration. The cell-scaffold interactions were analyzed by cell proliferation and their morphology observed in SEM. The results showed that the cell proliferation was significantly increased (p ≤ 0.05) in PLLA/PAA/Col I&III scaffolds compared to PLLA and PLLA/PAA nanofibrous scaffolds. The abundance and accessibility of adipose derived stem cells (ADSCs) may prove to be novel cell therapeutics for dermal tissue regeneration. The differentiation of ADSCs was confirmed using collagen expression and their morphology by CMFDA dye extrusion technique. The current study focuses on the application of PLLA/PAA/Col I&III nanofibrous scaffolds for skin tissue engineering and their potential use as substrate for the culture and differentiation of ADSCs. The objective for inclusion of a novel cell binding moiety like PAA was to replace damaged extracellular matrix and to guide new cells directly into the wound bed with enhanced proliferation and overall organization. This combinatorial epitome of PLLA/PAA/Col I&III nanofibrous scaffold with stem cell therapy to induce the necessary paracrine signalling effect would favour faster regeneration of the damaged skin tissues.     

Biocompatibility evaluation of protein-incorporated electrospun polyurethane-based scaffolds with smooth muscle cells for vascular tissue engineering

Nanotechnology has enabled the engineering of a variety of materials to meet the current challenges and needs in vascular tissue regeneration. In this study, four different kinds of native proteins namely collagen, gelatin, fibrinogen, and bovine serum albumin were incorporated with polyurethane (PU) and electropsun to obtain composite PU/protein nanofibers. SEM studies showed that the fiber diameters of PU/protein scaffolds ranged from 245 to 273 nm, mimicking the nanoscale dimensions of native ECM. Human aortic smooth muscle cells (SMCs) were cultured on the electrospun nanofibers, and the ability of the cells to proliferate on different scaffolds was evaluated via a cell proliferation assay. Cell proliferation on PU/Coll nanofibers was found the highest compared to other electrospun scaffolds and it was 42 % higher than the proliferation on PU/Fib nanofibers after 12 days of cell culture. The cell–biomaterial interaction studies by SEM confirmed that SMCs adhered to PU/Coll and PU/Gel nanofibers, with high cell substrate coverage, and both the scaffolds promoted cell alignment. The functionality of the cells was further demonstrated by immunocytochemical analysis, where the SMCs on PU/Coll and PU/Gel nanofibers expressed higher density of SMC proteins such as alpha smooth muscle actin and smooth muscle myosin heavy chain. Cells expressed biological markers of SMCs including aligned spindle-like morphology on both PU/Coll and PU/Gel with actin filament organizations, better than PU/Fib and PU/BSA scaffolds. Our studies demonstrate the potential of randomly oriented elastomeric composite scaffolds for engineering of vascular tissues causing cell alignment.     

Poly(L-lactic acid) nanocylinders as nanofibrous structures for macroporous gelatin scaffolds

Electrospun Nanofiber sheets have been shown to mimic the structure of extracellular matrix (ECM). Although these nanofibers have shown great potential for use as tissue engineering scaffolds, it is difficult for the electrospun nanofiber based sheets to be shaped into the desired three-dimensional structure. In this study, poly(L-lactic acid) (PLLA), a biodegradable and biocompatible polyester, was electrospun to produce nanofibers that were treated with an amino group containing base in order to fabricate polymeric nanocylinders. The aspect ratio of the PLLA nanocylinders was tunable by varying the aminolysis time and density of the amino group containing base. The effects of changes in nanofibrous morphology of the PLLA nanocylinders/macro-porous gelatin scaffolds on cell adhesion and proliferation were evaluated. The results revealed different cell morphology, adhesion, and proliferation in the nanocylinders composite gelatin scaffold versus gelatin scaffold alone. Confocal laser scanning microscopy observation showed more spreading and a more flattened cell morphology after NIH3T3 cells were cultured on PLLA nanocylinders/gelatin scaffolds for 10 hours and 4 days. These results indicate that the gelatin/PLLA nanocylinder composite is a promising way to fabricate 3D nanofibrous scaffolds that accelerates cell adhesion and proliferation for tissue engineering.     

纳米纤维组织工程支架及其纳米效应研究进展

综述了纳米纤维组织工程支架的最新研究进展,评述了其制备技术、特点及其存在的纳米效应.指出天然细胞外基质为三维纳米纤维结构,其纤维连续,直径为纳米级,包含比例确定的纳米与微米空间,且与细胞存在纳米水平的相互作用;然而,目前的人工纤维支架,其纤维直径多为微米或数百纳米,或者缺乏纳米空间.采用生物纳米技术获得的细菌纤维素纳米纤维,其直径小于10 nm,自身呈三维网状结构,富含纳米空间,是构建新一代纳米组织工程支架的理想材料.     

Biomimetic properties of an injectable chitosan/nano-hydroxyapatite/collagen composite

To meet the challenges of designing an injectable scaffold and regenerating bone with complex three-dimensional (3D) structures, a biomimetic and injectable hydrogel scaffold based on nano-hydroxyapatite (HA), collagen (Col) and chitosan (Chi) is synthesized. The chitosan/nano-hydroxyapatite/collagen (Chi/HA/Col) solution rapidly forms a stable gel at body temperature. It shows some features of natural bone both in main composition and microstructure. The Chi/HA/Col system can be expected as a candidate for workable systemic minimally invasive scaffolds with surface properties similar to physiological bone based on scanning electron microscopic (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results.     

Stem cell differentiation on electrospun nanofibrous substrates for vascular tissue engineering

Nanotechnology has enabled the engineering of a variety of materials to meet the current challenges and requirements in vascular tissue regeneration. In our study, poly-l-lactide (PLLA) and hybrid PLLA/collagen (PLLA/Coll) nanofibers (3:1 and 1:1) with fiber diameters of 210 to 430 nm were fabricated by electrospinning. Their morphological, chemical and mechanical characterizations were carried out using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR), and tensile instrument, respectively. Bone marrow derived mesenchymal stem cells (MSCs) seeded on electrospun nanofibers that are capable of differentiating into vascular cells have great potential for repair of the vascular system. We investigated the potential of MSCs for vascular cell differentiation in vitro on electrospun PLLA/Coll nanofibrous scaffolds using endothelial differentiation media. After 20 days of culture, MSC proliferation on PLLA/Coll(1:1) scaffolds was found 256% higher than the cell proliferation on PLLA scaffolds. SEM images showed that the MSC differentiated endothelial cells on PLLA/Coll scaffolds showed cobblestone morphology in comparison to the fibroblastic type of undifferentiated MSCs. The functionality of the cells in the presence of ‘endothelial induction media’, was further demonstrated from the immunocytochemical analysis, where the MSCs on PLLA/Coll (1:1) scaffolds differentiated to endothelial cells and expressed the endothelial cell specific proteins such as platelet endothelial cell adhesion molecule-1 (PECAM-1 or CD31) and Von Willebrand factor (vWF). From the results of the SEM analysis and protein expression studies, we concluded that the electrospun PLLA/Coll nanofibers could mimic the native vascular ECM environment and might be promising substrates for potential application towards vascular regeneration.