Scaffolds For Vascular Tissue Engineering Research Articles

Fabrication of PCL/keratin composite scaffolds for vascular tissue engineering with catalytic generation of nitric oxide potential.

Tissue-engineered vascular grafts (TEVGs) have been proposed as a promising approach to fulfill the need for small-diameter blood vessel substitutes. However, common failure caused by thrombosis and neointimal proliferation after implantation has restricted their use in the clinic. Herein, a NO-generating scaffold for vascular tissue engineering was developed by coelectrospinning poly(ε-caprolactone) (PCL) with keratin. The morphology and surface chemical composition were characterized via SEM, ATR-FTIR spectroscopy and XPS. The biocomposite scaffold selectively enhanced the adhesion and growth of endothelial cells (ECs) while suppressing the proliferation of smooth muscle cells (SMCs) in the presence of GSH and GSNO due to the catalytic generation of NO. In addition, these mats displayed excellent blood compatibility by prolonging the blood-clotting time. In summary, these NO-generating PCL/keratin scaffolds have potential applications in vascular tissue engineering with rapid endothelialization and reduced SMC proliferation.

Biomimetic dual-oriented/bilayered electrospun scaffold for vascular tissue engineering

Natural blood vessels have a multi-layered, cell-specific oriented spatial structure, mimicking of this structure is a promising way for blood vessel regeneration. In this study, a newly developed dual-oriented/bilayered small-diameter tubular scaffold was electrospun using a mixture of poly (ε-caprolactone) (PCL), poly (D, L-lactide-co-glycolide) (PLGA) and gelatin. The nanofiber orientations of the bilayers were spatially perpendicular to each other, aiming at guiding cell-specific orientation of smooth muscle cells (SMCs) and endothelial cells (ECs) in vitro respectively. The results showed that the hydrophilicity of scaffold was greatly improved by gelatin, and the mechanical property of this scaffold was the best among all. The in vitro degradation demonstrated that by mixing of three biodegradable polymers, a relatively fast degradation rate was achieved. After SMCs and ECs were seeded on scaffolds, cell viability, cellular morphology, and cytoskeleton behavior were investigated. The results revealed that as-electrospun scaffolds could promote both SMCs and ECs proliferation. Moreover, topographic cues offered by oriented nanofibers could guide the growth and orientation of SMCs and ECs. Therefore, the dual-oriented/bilayered electrospun scaffold is a superior structural and functional analogue to natural blood vessel and a potential candidate for vascular tissue engineering.

Development and mechanical characterization of bilayer tubular scaffolds for vascular tissue engineering applications

Poly(l-lactide-co-e-caprolactone) (PLCL) is a potential material to fabricate scaffolds for vascular tissue engineering. In this work, scaffolds with a multilayered structure comprising a combination of porous and fibrous structures were developed. PLCL was used to fabricate the inner layer of the tubular scaffolds using the freeze-drying technique. The inner layer was then covered by an outer layer fabricated by the melt-spinning technique. The morphology and physical structure of the scaffolds were evaluated through SEM micrographs. The freeze-drying technique formed a porous structure, while the melt-spinning method formed a fibrous structure for the bilayer scaffolds. Physicochemical properties were also investigated by DSC and FTIR measurements; no new functional groups were found to have formed during the freeze-drying or melt-spinning processes. Mechanical properties and fracture mechanism under a tensile loading condition were carefully analyzed to characterize the deformation and fracture behaviors. It was found that the bilayer scaffolds exhibited better mechanical properties than single-layer scaffolds with higher maximum stress at 675.41 kPa, strain at maximum stress at 69.42%, fracture energy at 412.45 kJ/m3 and burst pressure at 147.93 kPa. Porosity, swelling ratio and in vitro biodegradation were measured to ensure its suitability for vascular tissue applications. The bilayer scaffolds with both porous and fibrous structures meet the requirements for vascular tissue engineering.

Physico-mechanical and in vitro characterization of electrically conductive electrospun nanofibers of poly urethane/single walled carbon nano tube by great endothelial cells adhesion for vascular tissue engineering

Cardiovascular diseases (CVD) because of blood vessel disease are considered as one of the most frequent causes for mortality in all over the world. Recently, blood vessel tissue engineering is identified as one the promising strategies in order to overcome CVD. Accordingly, using Nano technology provides many benefits in blood vessel tissue engineering. In Present research Unique electrical, mechanical and biochemical properties of SWNT combined with electrospun polyurethane nanofiber was investigated as a functional composite scaffold for vascular tissue engineering. SWNT and polyurethane nanofibers incorporation indicated a biomechanical behavior similar to native artery. The scaffold morphological properties have been investigated by the use of scanning electron microscopy. With respect to the results, nanofiber diameter distribution was narrowed down by increasing SWNT content, while mean nanofiber diameter increased from 40 nm up to 140 nm. Physico-chemical characterization using FTIR, DSC, XRD and Raman test, demonstrated the nanoparticle appropriate dispersion and interaction to the polyurethane macromolecule. Along with increasing SWNT content up to the 2% (W/W) ultimate stress and young modulus increased 3 and 11 time, compared to pure PU, respectively. Structures electrical conductivity was increased from 0.0013 s/cm to 0.36 s/cm along with the increasing of SWNT content up to 2%. SWNT unique properties modulated samples hydrophilicity, and also contact angle of nanofiber scaffolds decreased from 1000 to 770. By passing 7 days, in vitro cell culture demonstrated dense layer of endothelial cells, which is crucial for blood vessel tissue engineering. Obtained results confirmed that electrospun poly urethane-SWNT scaffold could be considered as an appropriate candidate for blood vessel tissue engineering.

Poly(ε‐caprolactone)/keratin/heparin/VEGF biocomposite mats for vascular tissue engineering

Vascular endothelial growth factor (VEGF) is an effective growth and angiogenic cytokine, which stimulates proliferation and survival of endothelial cells, and promotes angiogenesis and vascular permeability. Binding VEGF with heparin could protect it from rapid degradation, subsequently allowing it to be controlled release. Primarily, poly(ε-caprolactone) (PCL) and keratin were coelectrospun, followed by conjugating with heparin and subsequently binding VEGF. The loaded heparin and VEGF on these mats were quantified, respectively. The surface characteristics of mats were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The VEGF delivery results indicated these mats could sustainably release VEGF for 2 weeks. Cell viability assays suggested these mats were valid to accelerate human umbilical vein endothelial cells (HUVECs) proliferation, while inhibit human umbilical arterial smooth muscle cells (HUASMCs) growth under the combined actions of VEGF and heparin. The results tested by blood clotting times (APTT, PT, and TT), hemolysis, and platelet adhesion indicated the mats were blood compatible. To sum up, these biocomposite mats are ideal scaffolds for vascular tissue engineering.

PCL/sulfonated keratin mats for vascular tissue engineering scaffold with potential of catalytic nitric oxide generation.

Heparin-like polymers have a good anticoagulant effect due to some groups similar to heparin. Herein, sulfonated keratin(SK) was prepared by chain transfer radical polymerization of 3-sulfopropyl methacrylate(SPMA) to improve blood coagulation nature of keratin. Poly(ε-caprolactone)(PCL)/SK nanofibrous mats with the ratio of 7 and 3 were then fabricated by electrospinning. In vitro cytotoxicity and blood compatibility tests were performed to assess the biocompatibility. Viability of NIH 3T3 cells on PCL/SK mats was higher than that on the pristine PCL mats, indicating their good cytocompatibility. These sulfonated keratin-containing mats enhanced endothelial cell growth, while inhibited smooth muscle cell proliferation and reduced platelet adhesion in the presence of GSH and GSNO, as a result of NO generation. Furthermore, the biocomposite mats prolonged the activated partial thromboplastin time(APTT) effectively without hemolysis. Taken together, PCL/SK mats are potential for applications in vascular tissue engineering.

Shear-resistant hydrogels to control permeability of porous tubular scaffolds in vascular tissue engineering.

Aiming to perfuse porous tubular scaffolds for vascular tissue engineering (VTE) with controlled flow rate, prevention of leakage through the scaffold lumen is required. A gel coating made of 8% w/v alginate and 6% w/v gelatin functionalized with fibronectin was produced using a custom-made bioreactor-based method. Different volumetric proportions of alginate and gelatin were tested (50/50, 70/30, and 90/10). Gel swelling and stability, and rheological, and uniaxial tensile tests reveal superior resistance to the aggressive biochemical microenvironment, and their ability to withstand physiological deformations (~10%) and wall shear stresses (5-20 dyne/cm2). These are prerequisites to maintain the physiologic phenotypes of vascular smooth muscle cells and endothelial cells (ECs), mimicking blood vessels microenvironment. Gels can induce ECs proliferation and colonization, especially in the presence of fibronectin and higher percentages of gelatin. The custom-designed bioreactor enables the development of reproducible and homogeneous tubular gel coating. The permeability tests show the effectiveness of tubular scaffolds coated with 70/30 alginate/gelatin gel to occlude wadding pores, and therefore prevent leakages. The synthesized double-layered tubular scaffolds coated with alginate/gelatin gel and fibronectin represent both promising substrate for ECs and effective leakproof scaffolds, when subjected to pulsatile perfusion, for VTE applications.

Electrospun microporous gelatin–polycaprolactone blend tubular scaffold as a potential vascular biomaterial

AbstractThe work reported involved the fabrication of an electrospun tubular conduit of a gelatin and polycaprolactone (PCL) blend as an adventitia‐equivalent construct. Gelatin was included as the matrix for increased biocompatibility with the addition of PCL for durability. This is contrary to most of the literature available for biomaterials based on blends of gelatin and PCL where PCL is the major matrix. The work includes the assiduous selection of key electrospinning parameters to obtain smooth bead‐free fibres with a narrow distribution of pore size and fibre diameter. Few reports elucidate the optimization of all electrospinning parameters to fabricate tubular conduits with a focus on obtaining homogeneous pores and fibres. This stepwise investigation would be unique for the fabrication of gelatin–PCL electrospun tubular constructs. The fabricated microfibrous gelatin–PCL constructs had pores of size ca 50–100 μm reportedly conducive for cell infiltration. The measured value of surface roughness of 57.99 ± 17.4 nm is reported to be favourable for protein adhesion and cell adhesion. The elastic modulus was observed to be similar to that of the tunica adventitia of the native artery. Preliminary in vitro and in vivo biocompatibility tests suggest safe applicability as a biomaterial. Minimal cytotoxicity was observed using MTT assay. Subcutaneous implantation of the scaffold demonstrated acute inflammation which decreased by day 15. The findings of this study could enable the fabrication of smooth bead‐free microfibrous gelatin–PCL tubular construct as viable biomaterial which can be included in a bilayer or a trilayer scaffold for vascular tissue engineering. © 2019 Society of Chemical Industry

Fabrication and Characterization of Bioresorbable Drug-coated Porous Scaffolds for Vascular Tissue Engineering.

Bioresorbable polymers have been studied for several decades as attractive candidates for promoting the advancement of medical science and bio-technology in modern society. In particular, with a well-defined architecture, bioresorbable polymers have prominent advantages over their bulk counterparts for applications in biomedical and implant devices, such as cell delivery, scaffolds for tissue engineering, and hydrogels as well as in the pharmaceutical fields. Biocompatible implant devices based on bioresorbable materials (for instance, bioresorbable polymers that combine the unique advantages of biocompability and easy handling) have emerged as a highly active field due to their promising applications in artificial implant systems and biomedical devices. In this paper, we report an approach to fabricate porous polycaprolactone (PCL) scaffolds using a 3D printing system. And its surface was treated to a hydrophilic surface using plasma treatment. Then, the aspirin and atorvastatin calcium salt mixture was dip coated onto the surface. The drug coating technology was used to deposit the drug material onto the scaffold surface. Our porous PCL scaffold was coated with aspirin and atorvastatin calcium salt to reduce the blood LDL cholesterol and restenosis. These results suggest that our approach may provide a promising scaffold for developing bioresorbable drug-delivery-biomaterials. We further demonstrate that our bioresorbable medical device can be used as vascular scaffolds to provide a wide range of applications for the design of medical devices.

Electrospun cellulose Nano fibril reinforced PLA/PBS composite scaffold for vascular tissue engineering

Today, tissue engineered scaffolds made by electrospinning are becoming a central focus of vascular prostheses research due to their ability to assist native tissue recovery. Compared to a single material, multifunctional composite scaffold could provide more suitable microenvironment for the tissue regeneration. In this study, electrospun composite scaffolds are developed by reinforcing a matrix of poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) by cellulose nano-fibrils (CNFs). Initially, PLA/PBS fibrous scaffolds with different ratio were prepared. The best properties and bioactivity of the scaffolds were obtained at equal ratio of PLA and PBS. Overall performance of electrospun scaffolds improved greatly by introduction of CNF into the PLA/PBS scaffolds. The developed composite scaffolds were found to meet some of the essential requirements for vascular tissue regeneration. They showed a uniform fibrous structure with desirable size dimension, cell-friendly surface characteristics, sustainable biodegradation behaviour and sustainable mechanical property compared to native tissue. In addition, the CNF composite scaffolds supported attachment and proliferation of human fibroblast cells more than PLA, PBS or their blends alone. Overall the developed composite scaffolds demonstrated their potency for vascular tissue engineering application.

An electrospun citric acid modified polyvinyl alcohol scaffold for vascular tissue engineering

The main aim of this study is to fabricate an electrospun citric acid modified polyvinyl alcohol polyester that is biodegradable with non-toxic by-products and can be used for the culture of vascular smooth muscle cells. In this study, we have optimized the conditions for the electrospinning process of this polyester. The fibre morphology was studied by scanning electron microscopy which indicated that the fibre diameter was optimum at a range of 200 to 700 µm at 5% concentration and flow rate of 0.3 mL/h. The membranes were characterized for the change in structural aspects at the molecular level. The results showed development of more crystalline domains on electrospinning. The surface characteristics were also explored. Cell culture studies confirmed that the electrospun scaffold supported the attachment and proliferation of smooth muscle cells, which was evident from the cell proliferation assay. Hence, the electrospun polyester scaffolds are non-toxic and biocompatible with vascular smooth muscle cells, and find promising potential as scaffolds for vascular tissue engineering.

Controllable fiber orientation and nonlinear elasticity of electrospun nanofibrous small diameter tubular scaffolds for vascular tissue engineering

Biomimetic structures play an important role in controlling the cell behaviors of adhesion, proliferation, migration, and differentiation, which is beneficial for the regeneration of defective tissues. Scaffolds with a biomimetic structure are highly desirable in tissue engineering. In this study, we successfully fabricated three different types of tubular scaffold with randomly, circumferentially, and axially aligned structures, using synthetic bioabsorbable poly(L-lactide-co-caprolactone) via electrospinning. Pre-extension treatment of the tubular scaffolds provided nonlinear elasticity that mimicked the nonlinear elasticity of arteries in the human body, which protects these blood vessels from damage. We measured the nonlinear elasticity, fatigue properties, compliance, and burst pressure of the tubular scaffolds, and the results indicated that the properties of the scaffolds matched those of native vessels reported in the literature. Furthermore, human umbilical vein endothelial cells were cultured on random and aligned fibers, and the results revealed that the cells proliferated well on nanofibrous mats with the three different fiber orientation directions, and the aligned fibers facilitated the orientation of cells in the direction of alignment of the fibers. Therefore, the aligned tubular scaffolds might have potential in vascular tissue engineering.

Modulating smooth muscle cell response by the release of TGFβ2 from tubular scaffolds for vascular tissue engineering

Tissue engineering has gained considerable attention in the development of small diameter tissue engineered vascular grafts (TEVGs) for treating coronary heart disease. A properly designed acellular and biodegradable TEVG must encourage the infiltration and growth of vascular smooth muscle cells (SMCs). Our group has previously shown that increasing levels of TGFβ2 can differentially modulate SMC migration and proliferation. In this study, tubular electrospun scaffolds loaded with TGFβ2 were fabricated using various ratios of gelatin/polycaprolactone (PCL), resulting in scaffolds with porous nano-woven architecture suitable for tissue ingrowth. Scaffold morphology, degradation rate, TGβ2 release kinetics, and bioactivity were assessed. TGFβ2 was successfully integrated into the electrospun biomaterial that resulted in a differential release profile depending on the gelatin/PCL ratio over the course of 42 days. Higher TGFβ2 elution was obtained in scaffolds with higher gelatin content, which may be related to the biodegradation of gelatin in culture media. The biological activity of the released TGFβ2 was evaluated by its ability to affect SMC proliferation as a function of its concentration. SMCs seeded on TGFβ2-loaded scaffolds also showed higher densities and infiltration after 5 days in culture as compared to scaffolds without TGFβ2. Our results demonstrate that the ratio of synthetic and natural polymers in electrospun blends can be used to tune the release of TGFβ2. This method can be used to intelligently modulate the SMC response in gelatin/PCL scaffolds making the TGFβ2-loaded conduits attractive for cardiovascular tissue engineering applications.

Blood-compatible Polyaniline Coated Electrospun Polyurethane Fiber Scaffolds for Enhanced Adhesion and Proliferation of Human Umbilical Vein Endothelial Cells

The endothelialization and anti-thrombotic abilities of tissue engineered vascular scaffolds are considered to be effective properties for improving the performance small-caliber vascular scaffolds. For this purpose, we designed and developed electrically conductive fibrous scaffolds based on polyaniline coated polyurethane (PANI-PU) electrospun fibers for vascular tissue engineering applications. The porosity of PANI-PU fibers was 75.27±2.04 %. The obtained PANI-PU fibers were characterized by SEM observations, XPS analysis, water contact angle (WCA) measurement and mechanical property. The PANI functionalization aimed to improve the performance of anticoagulation and endothelialization. The WCA of PAIN-PU decreased to 35° from 135° of PU fibers. Blood compatibility and cytocompatibility were compared before and after PANI coating. The adhered platelet cells on PANI-PU was 6.87×105/cm2 and plasma recalcification time was 123 s. Platelet adhesion and plasma recalcification time test showed that the PANI-PU scaffolds had a certain anticoagulant effect. The hemolysis rate of PANI-PU fibers was 0.14 %, which showed that the PANI-PU scaffolds could be used as blood contact materials. The observation of endothelial cell proliferation and morphology in human umbilical vein endothelial cells showed that PANI-PU fibers were more beneficial to cell adhesion, proliferation and extension than that of PU fibers. The results demonstrates the PANI coated electrospun PU fibers have great potential in application as small-diameter vascular grafts and this work shows new insights into conductive scaffolds for vascular tissue engineering.

Electrochemical fabrication of a biomimetic elastin-containing bi-layered scaffold for vascular tissue engineering

Biomimetic tissue-engineered vascular grafts (TEVGs) have immense potential to replace diseased small-diameter arteries (<4 mm) for the treatment of cardiovascular diseases. However, biomimetic approaches developed thus far only partially recapitulate the physicochemical properties of the native vessel. While it is feasible to fabricate scaffolds that are compositionally similar to native vessels (collagen and insoluble elastic matrix) using freeze-drying, these scaffolds do not mimic the aligned topography of collagen and elastic fibers found in native vessels. Extrusion-based scaffolds exhibit anisotropic collagen orientation but these scaffolds are compositionally dissimilar (cannot incorporate insoluble elastic matrix). In this study, an electrochemical fabrication technique was employed to develop a biomimetic elastin-containing bi-layered collagen scaffold which is compositionally and structurally similar to native vessels and the effect of insoluble elastin incorporation on scaffold mechanics and smooth muscle cell (SMC) response was investigated. Further, the functionality of human umbilical vein endothelial cells (HUVECs) on the scaffold lumen surface was assessed via immunofluorescence. Results showed that incorporation of insoluble elastin maintained the overall collagen alignment within electrochemically aligned collagen (ELAC) fibers and this underlying aligned topography can direct cellular orientation. Ring test results showed that circumferential orientation of ELAC fibers significantly improved scaffold mechanics. Real-time PCR revealed that the expression of α-smooth muscle actin (Acta2) and myosin heavy chain (MyhII) was significantly higher on elastin containing scaffolds suggesting that the presence of insoluble elastin can promote contractility in SMCs. Further, mechanical properties of the scaffolds significantly improved post-culture indicating the presence of a mature cell-synthesized and remodeled matrix. Finally, HUVECs expressed functional markers on collagen lumen scaffolds. In conclusion, electrochemical fabrication is a viable method for the generation of a functional biomimetic TEVG with the potential to be used in bypass surgery.

Impact of setup orientation on blend electrospinning of poly-ε-caprolactone-gelatin scaffolds for vascular tissue engineering.

This article explores the effect of horizontal and vertical setups on blend electrospinning with two polymers having vastly different properties - poly-ε-caprolactone and gelatin, and subsequent effect of the resulting microstructure on viability of seeded cells. Poly-ε-caprolactone and gelatin of varying blend concentrations were electrospun in horizontal and vertical setup orientations. NIH 3T3 fibroblasts were seeded on these scaffolds to assess cell viability changes in accordance with change in microstructure. Blend electrospinning yielded a heterogeneous microstructure in the vertical orientation beyond a critical concentration of gelatin, and a homogeneous microstructure in the horizontal orientation. Unblended poly-ε-caprolactone electrospinning showed no significant difference in fibre diameter or pore size in either orientation. Mechanical testing showed reduced elasticity when poly-ε-caprolactone is blended with gelatin but an overall increase in tensile strength in the vertically spun samples. Cells on vertically spun samples showed significantly higher viabilities by day 7. The composite microstructure obtained in vertically spun poly-ε-caprolactone -gelatin blends has a positive effect on viability of seeded cells. Such scaffolds can be considered suitable candidates for cardiovascular tissue engineering where cell infiltration is crucial.

Heparinized PCL/keratin mats for vascular tissue engineering scaffold with potential of catalytic nitric oxide generation

Heparins are capable of improving blood compatibility, enhancing HUVEC viability, while inhibiting HUASMC proliferation. Combination of biodegradable poly(ε-caprolactone) (PCL) with keratin and heparins would provide an anticoagulant and endothelialization supporting environment for vascular tissue engineering. Herein, PCL and keratin were first coelectrospun and then covalently conjugated with heparins. The resulting mats were surface-characterized by ATR-FTIR, SEM, WCA, and XPS. Cell viability data showed that the heparinized PCL/keratin mats could motivate the adhesion and growth of HUVEC, while inhibit HUASMC proliferation. In addition, these mats could prolong blood clotting time and reduce platelet adhesion as well as no erythrolysis. Interestingly, these mats could catalyze the NO donor in blood to release NO, which could enhance endothelial cell growth, while decrease smooth muscle cell proliferation and platelet adhesion. In summary, the heparinized mats would be a good candidate as a scaffold for vascular tissue engineering. This study is novel in that we prepared a type of heparinized tissue scaffold that could catalyze the NO donor to release NO to regulate endothelialization without angiogenesis and thrombus formation.

The deposition of thin titanium-nitrogen coatings on the surface of PCL-based scaffolds for vascular tissue engineering

Biodegradable polymer scaffolds for tissue engineering is a promising technology for therapies of patients suffering from the loss of tissue or its function including cardiac tissues. However, limitations such as hydrophobicity of polymers prevent cell attachment, cell conductivity, and endothelialization. Plasma modification of polymers allows producing materials for an impressive range of applications due to their unique properties. Here, we demonstrate the possibility of bioresorbable electrospun polycaprolacton (PCL) scaffold surface modification by reactive magnetron sputtering of the titanium target in a nitrogen atmosphere. The influence of the plasma treatment time on the structure and properties of electrospun PCL scaffolds was studied. We show that the plasma treatment does not change the physico-mechanical properties of electrospun PCL scaffolds, leads to an increase in PCL scaffold biocompatibility, and, simultaneously, increases their hydrophilicity. In conclusion, this modification method opens a route to producing scaffolds with enhanced biocompatibility for tissue engineered vascular grafts.

3D-printed Tubular Scaffolds for Vascular Tissue Engineering

Biomedical engineering is the application of engineering principles and design concepts to medicine and biology for healthcare purposes. Much of the work in biomedical engineering consists of research and development, spanning a broad array of subfields like biomechanics, genetic, neural, pharmaceutical, medical devices and tissue engineering among others. Tissue engineering has emerged as a key discipline for organ and tissue regeneration, in which compatibility with final user and a fast regeneration are still major challenges. Recently, three-dimensional printing has arose as an alternative system for producing biomaterials devices, such as scaffolds for tissue engineering. The proliferation of murine fibroblasts NIH/3T3, widely used in tissue engineering studies, into polycaprolactone scaffolds has been assayed in this paper. This work aim to analyze the effect of different architectures of 3D tubular scaffolds with empty core on fibroblast proliferation, focusing the tissue engineering application. We determined the effect of manufacturing process parameters and scaffold design onto the cell proliferation. From results, it can be concluded that manufacturing parameters (printing speed, temperature, and flow rate) affected fibroblast growth rate up to 40-65%. Narrow pores produced by an increased material extrusion showed less fibroblast growth, possibly due to a hindered oxygen and nutrient exchange. Nevertheless, future experiments using different designs and scaffold's architecture must be done.

Polymer scaffolds for vascular tissue engineering fabricated by combined electrospinning and hot embossing

Although tissue engineering has shown great advances in recent years, creating proper mechanical properties and cell growth microenvironments is still challenging. In this study, electrospun nanofibrous membranes were hot embossed to develop three-dimensional hierarchical micro/nanostructures that load and culture human umbilical-vein endothelial cells (HUVECs). The hot-embossed membranes exhibited not only superior mechanical properties (the tensile strength was 7.01 ± 0.18 MPa and the tensile modulus was 166.91 ± 15.54 MPa), but also better cell viability evaluated through a CCK-8 assay and fluorescent dye. The grating and well arrays of the micropatterned fibre mats encouraged the HUVECs to proliferate. Therefore, the approach proposed in this paper—combined electrospinning and hot embossing—has bright prospects in biomedical applications for the use of polymer scaffold in tissue engineering.