Electrospun polycaprolactone (PCL) scaffolds embedded with europium hydroxide nanorods (EHNs) with enhanced vascularization and cell proliferation for tissue engineering applications (original) (raw)
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Biomacromolecules, 2012
The aim of this study was to fabricate nanofibrous scaffolds based on blends of a hydroxyl functionalized polyester (poly(hydroxymethylglycolide-co-ε-caprolactone), pHMGCL) and poly(ε-caprolactone) (PCL), loaded with bovine serum albumin (BSA) as a protein stabilizer and vascular endothelial growth factor (VEGF) as a potent angiogenic factor by means of a coaxial electrospinning technique. The scaffolds were characterized by scanning electron microscopy (SEM), fluorescence microscopy (FM), and differential scanning calorimetry (DSC). The scaffolds displayed a uniform fibrous structure with a fiber diameter around 700 nm. The release of BSA from the core of the fibers was studied by high performance liquid chromatography (HPLC), and it was shown that the coaxial scaffolds composed of blends of pHMGCL and PCL exhibited faster release than the comparative PCL scaffolds. VEGF was also incorporated in the core of the scaffolds, and the effect of the released protein on the attachment and proliferation of endothelial cells was investigated. It was shown that the incorporated protein preserved its biological activity and resulted in initial higher numbers of adhered cells. Thus, these bioactive scaffolds based on blends of pHMGCL/PCL loaded with VEGF can be considered as a promising candidate for tissue engineering applications.
Journal of Tissue Engineering and Regenerative Medicine, 2007
A major constraint in the use of biodegradable polymer scaffolds for vascular tissue engineering is poor cell adhesion and lack of signals for new tissue generation. The presence of extracellular matrix (ECM) within the scaffold is desirable for growth of endothelial cells and in vitro formation of remodelled vascular conduit. In this study, we have produced a hybrid scaffold by coating porous poly-caprolactone (PCL) film with biomimetic ECM components consisting of fibrin, gelatin, fibronectin, angiogenic growth factors and proteoglycans. Human umbilical vein endothelial cells (HUVECs) adhered, spread, proliferated and survived for long periods in culture on the hybrid scaffold. As compared to bare PCL, enhanced cell adhesion, spreading and cytoskeletal organization were demonstrated on the hybrid scaffold, using confocal microscopy of EC-actin stained with Texas red-conjugated phalloidin. Population doubling of endothelial cells (ECs) on the hybrid scaffold and bare scaffold was estimated as 42 h and 136 h, respectively, as assessed by a 3 Hthymidine uptake method. Analysis of proliferating cell nuclear antigen (PCNA) also indicated low proliferation on bare scaffold. Flow cytometric analysis of annexin V-stained cells showed poor survival of ECs on bare PCL as compared to the hybrid scaffold. Deposition of insoluble collagen and elastin was identified on the hybrid scaffold by cells recovered after 15 days and 30 days of EC culture, using fluorochrome-tagged specific antibodies and confocal microscopy, and the fluorescence intensity corresponding to elastin and collagen after 30 days was similar to that of 15 days. The results indicate that ECM deposition by endothelial cells is a regulated process without excesive accumulation after 30 days.
Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2008
Poor cell adhesion, cytotoxicity of degradation products and lack of biological signals for cell growth, survival, and tissue generation are the limitations in the use of a biodegradable polymer scaffold for vascular tissue engineering. We have fabricated a hybrid scaffold by integrating physicochemical characteristics of poly(e-caprolactone) (PCL) and biomimetic property of a composite of fibrin, fibronectin, gelatin, growth factors, and proteoglycans to improve EC growth on the scaffold. Solvent cast porous films of poly(ecaprolactone) was prepared using PEG as a porogen. Porosity varied between 5 and 200 lm, and FTIR spectroscopy confirmed structural aspects of PCL. Films kept in PBS for 60 days showed tensile strength and elongation matching native blood vessel. Slow degradation of the scaffold was demonstrated by gravimetric analysis and molecular weight determination. Human umbilical vein endothelial cell (HUVEC) adhesion and proliferation on bare films were minimal. FTIR spectroscopy and environmental scanning electron microscopy (ESEM) of PCL-fibrin hybrid scaffold confirmed the presence of fibrin composite on PCL film. HUVEC was subsequently cultured on hybrid scaffold, and continuous EC lining was observed in 15 and 30 days of culture using ESEM. Results suggest that the new hybrid scaffold can be a suitable candidate for cardiovascular tissue engineering.
Materials Science and Engineering: C, 2016
Polycaprolactone (PCL)/ hydroxyapatite nano-composites are among the best candidates for tissue engineering. However, interactions between nHAp and PCL are difficult to control leading to inhomogeneous dispersion of the bio-ceramic particles. Grafting of polymer chains at high density/chain length while promotes the phase compatibility may result in reduced HAp exposed surface area and therefore, bioactivity is compromised. This issue is addressed here by grafting PCL chains onto HAp nano-particles through ring opening polymerization of ε-caprolactone (PCL-g-HAp). FTIR and TGA analysis showed that PCL (6.9 wt%), was successfully grafted on the HAp. PCL/PCL-g-HAp nano-fibrous scaffold showed up to 10 and 33% enhancement in tensile strength and modulus, respectively, compared to those of PCL/HAp. The effects of HAp on the in vitro HAp formation was investigated for both the PCL/HAp and PCL/PCL-g-HAp scaffolds. Precipitation of HAp on the nano-composite scaffolds observed after 15 days incubation in simulated body fluid (SBF), as confirmed by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Human fibroblasts were seeded on PCL, PCL/HAp and PCL/PCL-g-HAp scaffolds. According to MTT assay, the highest cell proliferation was recorded for PCL/PCL-g-HAp nano-composite, at all time intervals (1-21 days, p<0.001). Fluorescent microscopy (of DAPI stained samples) and electron microscopy images showed that all nano-fibrous scaffolds (PCL, PCL/HAp, and PCL/PCL-g-HAp), were non-toxic against cells, while more cell adhesion, and the most uniform cell distribution observed on the PCL/PCL-g-HAp. Overall, grafting of relatively short chains of PCL on the surface of HAp nano-particles stimulates fibroblasts adhesion and proliferation on the PCL/PCL-g-HAp nano-composite.
Medical Science Monitor, 2017
Departmental sources Background: Electrospun nanofibers have widespread putative applications in the field of regenerative medicine and tissue engineering. When compared to naturally occurring collagen matrices, electrospun nanofiber scaffolds have two distinct advantages: they do not induce a foreign body reaction and they are not at risk for biological contamination. However, the exact substrate, structure, and production methods have yet to be defined. Material/Methods: In the current study, tubular-shaped poly(L-lactide-co-caprolactone) (PLCL) constructs produced using electrospinning technology were evaluated for their potential application in the field of tissue regeneration in two separate anatomic locations: the skin and the abdomen. The constructs were designed to have an internal diameter of 3 mm and thickness of 200 μm. Using a rodent model, 20 PLCL tubular constructs were surgically implanted in the abdominal cavity and subcutaneously. The constructs were then evaluated histologically using electron microscopy at 6 weeks post-implantation. Results: Histological evaluation and analysis using scanning electron microscopy showed that pure scaffolds by themselves were able to induce angiogenesis after implantation in the rat model. Vascularization was observed in both tested groups; however, better results were obtained after intraperitoneal implantation. Formation of more and larger vessels that migrated inside the scaffold was observed after implantation into the peritoneum. In this group no evidence of inflammation and better integration of scaffold with host tissue were noticed. Subcutaneous implantation resulted in more fibrotic reaction, and differences in cell morphology were also observed between the two tested groups. Conclusions: This study provides a standardized evaluation of a PLCL conduit structure in two different anatomic locations, demonstrating the excellent ability of the structure to achieve vascularization. Functional, histological, and mechanical data clearly indicate prospective clinical utilization of PLCL in critical size defect regeneration.
Journal of Functional Biomaterials
Endothelialization of artificial scaffolds is considered an effective strategy for increasing the efficiency of vascular transplantation. This study aimed to compare the biophysical/biocompatible properties of three different biodegradable fibrous scaffolds: Poly (ɛ-caprolactone) (PCL) alone, Poly Lactic-co-Glycolic Acid (PLGA) alone (both processed using Spraybase® electrospinning machine), and Coaxial scaffold where the fiber core and sheath was made of PCL and PLGA, respectively. Scaffold structural morphology was assessed by scanning electron microscope and tensile testing was used to investigate the scaffold tension resistance over time. Biocompatibility studies were carried out with human umbilical vein endothelial cells (HUVEC) and human vascular fibroblasts (HVF) for which cell viability (and cell proliferation over a 4-day period) and cell adhesion to the scaffolds were assessed by cytotoxicity assays and confocal microscopy, respectively. Our results showed that all biodeg...
An in vitro regenerated functional human endothelium on a nanofibrous electrospun scaffold
Biomaterials, 2010
The capacity of the luminal layer of an electrospun bi-layer scaffold composed of gelatin, elastin, polycaprolactone (PCL), and poliglecaprone (PGC) to promote endothelial regeneration was investigated using human aortic endothelial cells (HAECs). HAECs of different densities were cultured on a thin film of the luminal layer of the scaffold mounted on a cell crown for desired periods. Fluorescent images showed that HAECs formed a mono-layer within 24 h after having successfully adhered to the scaffold's surface. Scanning electron microscopy (SEM) revealed a satisfactory coverage by the HAECs. Death rates of HAECs populations determined by fluorescent staining were below 5% within the initial 3 days while the profile of proliferation exhibited an exponential increase within 11 days as determined by the 3-[4,5-dimethyl (thiazol-2yl)-3,5-diphery] tetrazolium bromide (MTT) assay. The functionalities of the endothelial monolayer were probed by ZO-1 staining for tight junction formation, by 6-keto-PGF 1a assay for prostacyclin (PGI 2 ) secretion, and by human platelets for its anti-thrombotic capability. The results indicated that the regenerated endothelium possessed normal functions associated with native endothelium. This study suggests that this electrospun bi-layer scaffold is a promising candidate for cardiovascular grafting for its capability of promoting the regeneration of a functional endothelium to prevent blood clotting in small diameter grafts.
ACS Biomaterials Science & Engineering, 2018
Next-generation tissue engineering exploits the body's own regenerative capacity by providing an optimal niche via a scaffold for the migration and subsequent proliferation of endogenous cells to the site of injury, enhancing regeneration and healing and bypassing laborious in vitro cell-culturing procedures. Such systems are also required to have a sufficient angiogenic capacity for the subsequent patency of implanted scaffolds. The exploitation of redox properties of nanodimensional ceria (nCeO 2) in in situ tissue engineering to promote cell adhesion and angiogenesis is poorly investigated. As a novel strategy, electrospun polycaprolactone based tissue-engineering scaffolds loaded with nCeO 2 were developed and evaluated for morphological and physicomechanical features. In addition, in vitro and in vivo studies were performed to show the ability of nCeO 2-containing scaffolds to enhance cell adhesion and angiogenesis. These studies confirmed that nCeO 2-containing scaffolds supported cell adhesion and angiogenesis better than bare scaffolds. Gene-expression studies had shown that angiogenesis-related factors such as HIF1α and VEGF were up-regulated. Overall results show that incorporation of nCeO 2 plays a key role in scaffolds for the enhancement of angiogenesis, cell adhesion, and cell proliferation and can produce a successful outcome in in situ tissue engineering.
Assessment of Electrospun Pellethane-Based Scaffolds for Vascular Tissue Engineering
Materials, 2021
We examined the physicochemical properties and the biocompatibility and hemocompatibility of electrospun 3D matrices produced using polyurethane Pellethane 2363-80A (Pel-80A) blends Pel-80A with gelatin or/and bivalirudin. Two layers of vascular grafts of 1.8 mm in diameter were manufactured and studied for hemocompatibility ex vivo and functioning in the infrarenal position of Wistar rat abdominal aorta in vivo (n = 18). Expanded polytetrafluoroethylene (ePTFE) vascular grafts of similar diameter were implanted as a control (n = 18). Scaffolds produced from Pel-80A with Gel showed high stiffness with a long proportional limit and limited influence of wetting on mechanical characteristics. The electrospun matrices with gelatin have moderate capacity to support cell adhesion and proliferation (~30–47%), whereas vascular grafts with bivalirudin in the inner layer have good hemocompatibility ex vivo. The introduction of bivalirudin into grafts inhibited platelet adhesion and does not l...