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Sheila Macneil - One of the best experts on this subject based on the ideXlab platform.
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development of a basement membrane substitute incorporated into an Electrospun Scaffold for 3d skin tissue engineering
Journal of Biomaterials and Tissue Engineering, 2014Co-Authors: Frazer J Bye, Anthony J Bullock, Rita Singh, Farshid Sefat, Sabiniano Roman, Sheila MacneilAbstract:A major challenge in the production of 3D tissue engineered skin is the recreation of the basement membrane region to promote secure attachment and yet segregation of keratinocytes from the dermal substitute impregnated with fibroblasts. We have previously shown that simple Electrospun Scaffolds provide fibres on which the cells attach, proliferate, and self-sort into epithelium and dermis. In a development of this in this study tri-layered Scaffolds were then Electrospun from poly L-lactic acid and poly hydroxybutyrate-co-hydroxyvalerate. In these a central layer of the Scaffolds comprising nano-porous/nano-fibrous poly hydroxybutyrate-co-hydroxyvalerate fibres was interwoven into the bulk micro-porous poly L-lactic acid microfibers to mimic the basement membrane. Keratinocytes and fibroblasts seeded onto these Scaffolds and cultured for 2 weeks showed that neither cell type was able to cross the central nano-porous barrier (shown by SEM, and fluorescence monitoring with CellTracker ™ ) while the micro-fibrous poly L-lactic acid provided a Scaffold on which keratinocytes could create an epithelium and fibroblasts could create a dermal substitute depositing collagen. Although cells did not penetrate this barrier the interaction of cells was still evident-essential for epithelial development.
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development of an ibuprofen releasing biodegradable pla pga Electrospun Scaffold for tissue regeneration
Biotechnology and Bioengineering, 2010Co-Authors: Irene Canton, Robert Mckean, Anthony J Ryan, Mirren Charnley, Keith A Blackwood, Calogero Fiorica, Sheila MacneilAbstract:Our aim was to develop a biodegradable fibrous dressing to act as a tissue guide for in situ wound repair while releasing Ibuprofen to reduce inflammation in wounds and reduce pain for patients on dressing changes. Dissolving the acid form of Ibuprofen (from 1% to 10% by weight) in the same solvent as 75% polylactide, 25% polyglycolide (PLGA) polymers gave uniformly loaded Electrospun fibers which gave rapid release of drug within the first 8 h and then slower release over several days. Scaffolds with 10% Ibuprofen degraded within 6 days. The Ibuprofen released from these Scaffolds significantly reduced the response of fibroblasts to major pro-inflammatory stimulators. Fibroblast attachment and proliferation on Scaffolds was unaffected by the addition of 1-5% Ibuprofen. Scaffolds loaded with 10% Ibuprofen initially showed reduced cell attachment but this was restored by soaking Scaffolds in media for 24 h. In summary, addition of Ibuprofen to Electrospun biodegradable Scaffolds can give acute protection of adjacent cells to inflammation while the Scaffolds provide an open 3D fibrous network to which cells can attach and migrate. By 6 days, such Scaffolds will have completely dissolved into the wound bed obviating any need for dressing removal.
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development of a 3d cell culture system for investigating cell interactions with Electrospun fibers
Biotechnology and Bioengineering, 2007Co-Authors: Tao Sun, John W Haycock, David Norton, Robert Mckean, Anthony J Ryan, Sheila MacneilAbstract:There are many variables to be considered in studying how cells interact with 3D Scaffolds used in tissue engineering. In this study we investigated the influence of the fiber diameter and interfiber spaces of 3D Electrospun fiber Scaffolds on the behavior of human dermal fibroblasts. Fibers of two dissimilar model materials, polystyrene and poly-L-lactic acid, with a broad range of diameters were constructed in a specifically developed 3D cell culture system. When fibroblasts were introduced to freestanding fibers, and encouraged to “walk the plank,” a minimum fiber diameter of 10 µm was observed for cell adhesion and migration, irrespective of fiber material chemistry. A distance between fibers of up to 200 µm was also observed to be the maximum gap that could be bridged by cell aggregates—a behavior not seen in conventional 2D culture. This approach has identified some basic micro-architectural parameters for Electrospun Scaffold design and some key differences in fibroblast growth in 3D. We suggest the findings will be of value for optimizing the integration of cells in these Scaffolds for skin tissue engineering. Biotechnol. Bioeng. 2007; 97: 1318–1328. © 2006 Wiley Periodicals, Inc.
Frank P T Baaijens - One of the best experts on this subject based on the ideXlab platform.
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tailoring fiber diameter in Electrospun poly ɛ caprolactone Scaffolds for optimal cellular infiltration in cardiovascular tissue engineering
Tissue Engineering Part A, 2009Co-Authors: Angelique Balguid, Anita Mol, Mieke H Van Marion, Ruud A Bank, Carlijn V C Bouten, Frank P T BaaijensAbstract:Despite the attractive features of nanofibrous Scaffolds for cell attachment in tissue-engineering (TE) applications, impeded cell ingrowth has been reported in Electrospun Scaffolds. Previous findings have shown that the Scaffold can function as a sieve, keeping cells on the Scaffold surface, and that cell migration into the Scaffold does not occur in time. Because fiber diameter is directly related to the pore size of an Electrospun Scaffold, the objective of this study was to systematically evaluate how cell delivery can be optimized by tailoring the fiber diameter of Electrospun poly(e- caprolactone) (PCL) Scaffolds. Five groups of Electrospun PCL Scaffolds with increasing average fiber diameters (3.4-12.1μm) were seeded with human venous myofibroblasts. Cell distribution was analyzed after 3 days of culture. Cell penetration increased proportionally with increasing fiber diameter. Unobstructed delivery of cells was observed exclusively in the Scaffold with the largest fiber diameter (12.1 μm). This Scaffold was subsequently evaluated in a 4-week TE experiment and compared with a poly(glycolic acid)-poly(4- hydroxybutyrate) Scaffold, a standard Scaffold used successfully in cardiovascular tissue engineering applications. The PCL constructs showed homogeneous tissue formation and sufficient matrix deposition. In conclusion, fiber diameter is a crucial parameter to allow for homogeneous cell delivery in Electrospun Scaffolds. The optimal Electrospun Scaffold geometry, however, is not generic and should be adjusted to cell size. © 2009, Mary Ann Liebert, Inc.
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tailoring fiber diameter in Electrospun poly ɛ caprolactone Scaffolds for optimal cellular infiltration in cardiovascular tissue engineering
Tissue Engineering Part A, 2009Co-Authors: Angelique Balguid, Ruud A Bank, Mieke H Van Marion, Carlijn Carlijn Bouten, Frank P T BaaijensAbstract:Despite the attractive features of nanofibrous Scaffolds for cell attachment in tissue-engineering (TE) applications, impeded cell ingrowth has been reported in Electrospun Scaffolds. Previous findings have shown that the Scaffold can function as a sieve, keeping cells on the Scaffold surface, and that cell migration into the Scaffold does not occur in time. Because fiber diameter is directly related to the pore size of an Electrospun Scaffold, the objective of this study was to systematically evaluate how cell delivery can be optimized by tailoring the fiber diameter of Electrospun poly(ɛ-caprolactone) (PCL) Scaffolds. Five groups of Electrospun PCL Scaffolds with increasing average fiber diameters (3.4–12.1 μm) were seeded with human venous myofibroblasts. Cell distribution was analyzed after 3 days of culture. Cell penetration increased proportionally with increasing fiber diameter. Unobstructed delivery of cells was observed exclusively in the Scaffold with the largest fiber diameter (12.1 μm). This s...
Gary L. Bowlin - One of the best experts on this subject based on the ideXlab platform.
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A preliminary study on amelogenin-loaded Electrospun Scaffolds
Journal of Bioactive and Compatible Polymers, 2013Co-Authors: Jennifer M. Mccool, Scott A Sell, Isaac A. Rodriguez, Yang Han, Gary L. BowlinAbstract:Amelogenin is a major enamel matrix protein onto which developing enamel forms. In the realm of tissue engineering, amelogenin has been studied and applied to periodontal and wound healing applications. This study introduces the first attempts of incorporating amelogenin within an Electrospun Scaffold. Amelogenin was extracted from porcine unerupted tooth buds and Electrospun with poly(glycolic acid) and poly(ϵ-caprolactone). Protein release kinetics, mechanical properties, fiber diameter, mineralization potential, and cell adhesion properties of the amelogenin-blended Scaffolds were studied and compared to the Electrospun poly(glycolic acid) and poly(ϵ-caprolactone) controls. Electrospun Scaffolds loaded with amelogenin were incubated in phosphate buffer saline. Protein quantification and morphological and mechanical analyses were conducted on the degraded Scaffolds, and the incubated phosphate buffer saline was also tested for protein content. Fresh Scaffolds were incubated overnight in conventional sim...
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macrophage functional polarization m1 m2 in response to varying fiber and pore dimensions of Electrospun Scaffolds
Biomaterials, 2013Co-Authors: Koyal Garg, Nicholas Pullen, Carole A Oskeritzian, John J Ryan, Gary L. BowlinAbstract:In this study, we investigated the effect of fiber and pore size of an Electrospun Scaffold on the polarization of mouse bone marrow-derived macrophages (BMMΦs) towards regenerative (M2) or inflammatory (M1) phenotypes. BMMΦs were seeded on Polydioxanone (PDO) Scaffolds Electrospun from varying polymer concentrations (60, 100, and 140 mg/ml). Higher polymer concentrations yielded larger diameter fibers with larger pore sizes and porosity. BMMΦ cultured on these Scaffolds showed a correlation between increasing fiber/pore size and increased expression of the M2 marker Arginase 1 (Arg1), along with decreased expression of the M1 marker inducible nitric oxide synthase (iNOS). Secretion of the angiogenic cytokines VEGF, TGF-β1 and bFGF was higher among cultures employing larger fiber/pore size Scaffolds (140 mg/ml). Using a 3D in vitro angiogenesis bead assay, we have demonstrated that the M2-like profile of BMMΦ induced by the 140 mg/ml is functional. Furthermore, our results show that the pore size of a Scaffold is a more critical regulator of the BMMΦ polarization compared to the fiber diameter. The study also shows a potential role for MyD88 in regulating M1 BMMΦ signaling on the large vs. small fiber/pore size PDO Scaffold. These data are instructive for the rationale design of implantable prosthetics designed to promote in situ regeneration.
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incorporating platelet rich plasma into Electrospun Scaffolds for tissue engineering applications
Tissue Engineering Part A, 2011Co-Authors: Scott A Sell, David G Simpson, Patricia S Wolfe, Jeffery J Ericksen, Gary L. BowlinAbstract:Platelet-rich plasma (PRP) therapy has seen a recent spike in clinical interest due to the potential that the highly concentrated platelet solutions hold for stimulating tissue repair and regeneration. The aim of this study was to incorporate PRP into a number of Electrospun materials to determine how growth factors are eluted from the structures, and what effect the presence of these factors has on enhancing Electrospun Scaffold bioactivity. PRP underwent a freeze-thaw-freeze process to lyse platelets, followed by lyophilization to create a powdered preparation rich in growth factors (PRGF), which was subsequently added to the electrospinning process. Release of protein from Scaffolds over time was quantified, along with the quantification of human macrophage and adipose-derived stem cell (ADSC) chemotaxis and proliferation. Protein assays demonstrated a sustained release of protein from PRGF-containing Scaffolds at up to 35 days in culture. Scaffold bioactivity was enhanced as ADSCs demonstrated increased proliferation in the presence of PRGF, whereas macrophages demonstrated increased chemotaxis to PRGF. In conclusion, the work performed in this study demonstrated that the incorporation of PRGF into Electrospun structures has a significant positive influence on the bioactivity of the Scaffolds, and may prove beneficial in a number of tissue engineering applications.
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measuring fiber alignment in Electrospun Scaffolds a user s guide to the 2d fast fourier transform approach
Journal of Biomaterials Science-polymer Edition, 2008Co-Authors: Chantal E Ayres, Gary L. Bowlin, Shekhar B Jha, Hannah R Meredith, James R Bowman, Scott C Henderson, David G SimpsonAbstract:In this study we describe how to use a two-dimensional fast Fourier transform (2D FFT) approach to measure fiber alignment in Electrospun materials. This image processing function can be coupled with a variety of imaging modalities to assign an objective numerical value to Scaffold anisotropy. A data image of an Electrospun Scaffold is composed of pixels that depict the spatial organization of the constituent fibers. The 2D FFT function converts this spatial information into a mathematically defined frequency domain that maps the rate at which pixel intensities change across the original data image. This output image also contains quantitative information concerning the orientation of objects in a data image. We discuss the theory and practice of using the frequency plot of the 2D FFT function to measure relative Scaffold anisotropy and identify the principal axis of fiber orientation. We note that specific degrees of Scaffold anisotropy may represent a critical design feature in the fabrication of tissue...
Clay Quint - One of the best experts on this subject based on the ideXlab platform.
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Tissue-engineered vessel derived from human fibroblasts with an Electrospun Scaffold.
Journal of tissue engineering and regenerative medicine, 2020Co-Authors: Clay QuintAbstract:Advanced cardiovascular disease often requires surgical revascularization for small diameter arterial bypass procedures, and there is a need for alternative grafts in those patients lacking autologous vein. A decellularized biological vessel with the characteristics of a small artery and the ability to remodel in vivo could replace currently available bypass grafts. In this study, a biodegradable Electrospun Scaffold was specifically designed to be placed in a biomimetic perfusion system to generate a tissue-engineered vessel from human dermal fibroblasts. The polyglycolic acid Electrospun Scaffold was co-electrosprayed with a sacrificial porogen microparticle, polyethylene oxide, to increase porosity and pore size. After a 10-week culture period in the biomimetic system, the tissue-engineered vessel derived from human fibroblasts was further processed with decellularization to form an allogeneic tissue-engineered vessel. The tissue-engineered vessel had a similar morphology by histological staining for collagen and elastin before and after decellularization. The mechanical properties (burst pressure, ultimate tensile strength, and elastic modulus) remained stable after decellularization and were on the same magnitude as a human saphenous vein. The decellularization processing demonstrated no loss of collagen, near complete removal of DNA, and no presence of intracellular proteins. The decellularized tissue-engineered vessel supported the growth of endothelial cells on the surface, and fibroblasts were able to migrate into the midportion of the matrix. Therefore, an Electrospun Scaffold provides a versatile biomaterial to create a decellularized tissue-engineered vessel derived from human dermal fibroblasts with morphological and mechanical properties for use as a small diameter vascular graft.
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Tissue engineered vessel from a biodegradable Electrospun Scaffold stimulated with mechanical stretch.
Biomedical materials (Bristol England), 2020Co-Authors: Jacob Hodge, Clay QuintAbstract:A tissue engineered vessel has the potential to provide an alternative small diameter vascular graft for patients with cardiovascular disease in need of surgical revascularization. In this study, a polyglycolic acid (PGA) Electrospun Scaffold seeded with human dermal fibroblasts was stimulated with circumferential mechanical stretch by a pulsatile perfusion system. The PGA Scaffold was fabricated using a custom electrospinning set-up to co-electrospray a sacrificial polyethylene oxide microparticle to increase pore size and bulk porosity. The tissue engineered vessel exposed to circumferential mechanical stretch was compared to an engineered vessel cultured under static conditions without any mechanical stimulation. The histology cross-sections demonstrated a similar thickness of engineered vessels with mechanical stretch and static, but on Masson's Trichrome stain there was nearly twice the amount of staining for collagen. The collagen content was quantified, and the collagen content was 60% greater in the human tissue engineered vessel exposed to mechanical stretch compared to the static vessel. The total collagen cross-linking was similar, but on a per collagen basis there was significantly more cross-linking in the static vessel over the stretch vessel. The stress-strain curve of the tissue engineered vessel with mechanical stretch demonstrated a statistically significantly greater ultimate tensile strength (UTS) of 1.86 ± 0.14 MPa (n = 6) and elastic modulus (EM) of 7.62 ± 0.39 MPa (n = 6) versus the static engineered vessel UTS of 0.31 ± 0.07 MPa (n = 5) and EM of 1.37 ± 0.21 MPa (n = 5). The primary determinant of the mechanical properties of the tissue engineered vessel correlated to the collagen content with minimal contribution of the collagen cross-linking. Therefore, the versatile properties of an Electrospun Scaffold are ideal in combination with a biomimetic culture system to generate a tissue engineered vessel composed of extracellular matrix suitable as a vascular graft.
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The improvement of cell infiltration in an Electrospun Scaffold with multiple synthetic biodegradable polymers using sacrificial PEO microparticles.
Journal of biomedical materials research. Part A, 2019Co-Authors: Jacob Hodge, Clay QuintAbstract:Electrospinning is a fabrication technique to generate three dimensional Scaffolds with a fiber structure that imitates extracellular matrix for tissue engineering constructs. The versatile characteristics of the electrospinning process yields designer Scaffolds made of biodegradable polymers or natural proteins with controllable fiber diameters, biodegradation, and mechanical properties. A limitation of conventional Electrospun Scaffolds is the dense fiber packing with low porosity that leads to poor cell infiltration. Electrospraying sacrificial polyethylene oxide (PEO) microparticles in combination with Electrospun Scaffolds are a method to increase porosity. We report the effectiveness of electrospraying PEO microparticles to increase porosity of the most commonly used biodegradable polymers: polyglycolic acid (PGA), poly (lactic-co-glycolic) acid (PLGA), and polycaprolactone (PCL). The biodegradable polymer Electrospun Scaffolds with the sacrificial PEO microparticles were found to have improved cell proliferation and infiltration with human fibroblasts compared to conventional Electrospun Scaffolds. The mechanical properties of the more robust PGA and PLGA had minor changes, but the more elastic PCL was observed to be weaker and less stiff after the removal of the PEO microparticles. Therefore, this study found PEO microparticles can increase porosity and cell infiltration with stable mechanical properties for a wide variety of biodegradable polymers in Electrospun Scaffolds.
Jiang Chang - One of the best experts on this subject based on the ideXlab platform.
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An Anisotropically and Heterogeneously Aligned Patterned Electrospun Scaffold with Tailored Mechanical Property and Improved Bioactivity for Vascular Tissue Engineering
ACS Applied Materials & Interfaces, 2015Co-Authors: He Xu, Haiyan Li, Qinfei Ke, Jiang ChangAbstract:The development of vascular Scaffolds with controlled mechanical properties and stimulatory effects on biological activities of endothelial cells still remains a significant challenge to vascular tissue engineering. In this work, we reported an innovative approach to prepare a new type of vascular Scaffolds with anisotropically and heterogeneously aligned patterns using electrospinning technique with unique wire spring templates, and further investigated the structural effects of the patterned Electrospun Scaffolds on mechanical properties and angiogenic differentiation of human umbilical vein endothelial cells (HUVECs). Results showed that anisotropically aligned patterned nanofibrous structure was obtained by depositing nanofibers on template in a structurally different manner, one part of nanofibers densely deposited on the embossments of wire spring and formed cylindrical-like structures in the transverse direction, while others loosely suspended and aligned along the longitudinal direction, forming a...
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An anisotropically and heterogeneously aligned patterned Electrospun Scaffold with tailored mechanical property and improved bioactivity for vascular tissue engineering.
ACS applied materials & interfaces, 2015Co-Authors: Jiang ChangAbstract:The development of vascular Scaffolds with controlled mechanical properties and stimulatory effects on biological activities of endothelial cells still remains a significant challenge to vascular tissue engineering. In this work, we reported an innovative approach to prepare a new type of vascular Scaffolds with anisotropically and heterogeneously aligned patterns using electrospinning technique with unique wire spring templates, and further investigated the structural effects of the patterned Electrospun Scaffolds on mechanical properties and angiogenic differentiation of human umbilical vein endothelial cells (HUVECs). Results showed that anisotropically aligned patterned nanofibrous structure was obtained by depositing nanofibers on template in a structurally different manner, one part of nanofibers densely deposited on the embossments of wire spring and formed cylindrical-like structures in the transverse direction, while others loosely suspended and aligned along the longitudinal direction, forming a three-dimensional porous microstructure. We further found that such structures could efficiently control the mechanical properties of Electrospun vascular Scaffolds in both longitudinal and transverse directions by altering the interval distances between the embossments of patterned Scaffolds. When HUVECs were cultured on Scaffolds with different microstructures, the patterned Scaffolds distinctively promoted adhesion of HUVECs at early stage and proliferation during the culture period. Most importantly, cells experienced a large shape change associated with cell cytoskeleton and nuclei remodeling, leading to a stimulatory effect on angiogenesis differentiation of HUVECs by the patterned microstructures of Electrospun Scaffolds, and the Scaffolds with larger distances of intervals showed a higher stimulatory effect. These results suggest that Electrospun Scaffolds with the anisotropically and heterogeneously aligned patterns, which could efficiently control the mechanical properties and bioactivities of the Scaffolds, might have great potential in vascular tissue engineering application.