scholarly journals Electrospinning of fibrous PHBV tissue engineering scaffolds: Fiber diameter control, fiber alignment and mechanical properties

2008 ◽  
Author(s):  
Ho-Wang Tong ◽  
Min Wang
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Fiber Diameter ◽  
Tissue Engineering Scaffolds ◽  
Fiber Alignment ◽  
Diameter Control

Preparation of Fibrous Scaffolds Containing Calcium and Silicon Species

2011 ◽  
Vol 493-494 ◽  
pp. 840-843
Author(s):  
Akiko Obata ◽  
Hiroki Ozasa ◽  
Julian R. Jones ◽  
Toshihiro Kasuga
Keyword(s):  
Tissue Engineering ◽  
Hybrid Materials ◽  
Fiber Diameter ◽  
Fiber Spinning ◽  
High Porosity ◽  
Cotton Wool ◽  
Tissue Engineering Scaffolds ◽  
Large Defect ◽  
Nanofibrous Structure ◽  
Versatile Technique

Materials for bone defect filling should have 3D macroporous structure and be flexible to be packed into complex defects with limited entrance space. Tissue engineering scaffolds should also mimic the structure and morphology of the host tissue. Electrospinning is a versatile technique to produce materials with micro/nanofibrous structure, large surface area and high porosity. Electrospun materials are very promising for tissue engineering due to the possibility of mimicking the fibrous structure of natural extra cellular matrix (ECM). Siloxane-containing vaterite (SiV)/poly (L-lactic acid) (PLLA) hybrids (SiPVH) with controlled silicate and calcium ions releasing ability has been produced in our group. They have also demonstrated good cell infiltration into the electrospun hybrid materials that had fiber diameters greater than 10 μm. However, these electrospun hybrid materials were planar (2D) and are not suitable for large defect regeneration. In this work, the development of a fabrication technique for the production of 3D cotton wool-like structures with fiber diameter in the range of 10 μm was performed. SiPVH cotton wool-like structure containing 0, 30 and 60 wt % SiV were prepared by blowing air in the direction perpendicular to fiber spinning. Si-vaterite particles and small pores were found on the surface of the fibers. The fiber diameter of the samples were found to be in the range of 10 ~ 20 μm. Stretch tests showed more than 50 % extension for the SiPVH cotton wool-like material containing 30 wt % SiV (SiPVH30). This extension was similar to that observed for the PLLA cotton wool-like material. The results suggest that the SiPVH30 cotton wool-like material are good candidates for bone tissue engineering scaffolds.

A novel biocompatible double network hydrogel consisting of konjac glucomannan with high mechanical strength and ability to be freely shaped

2015 ◽  
Vol 3 (9) ◽  
pp. 1769-1778 ◽  
Author(s):  
Zhiyong Li ◽  
Yunlan Su ◽  
Baoquan Xie ◽  
Xianggui Liu ◽  
Xia Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Cell Adhesion ◽  
Mechanical Strength ◽  
Synthetic Polymer ◽  
Natural Polymer ◽  
Tissue Engineering Scaffolds ◽  
Adhesion Properties ◽  
High Mechanical Strength ◽  
Double Network

A novel physically linked double-network (DN) hydrogel was prepared by natural polymer KGM and synthetic polymer PAAm. The DN hydrogels exhibit good mechanical properties, cell adhesion properties, and can be freely shaped, making such hydrogels promising for tissue engineering scaffolds.

Microcellular Injection Molding of Thermoplastic Polyurethane (TPU) Scaffolds Using Carbon Dioxide and Water as Co-Blowing Agents

2013 ◽  
Author(s):  
Hao-Yang Mi ◽  
Xin Jing ◽  
Lih-Sheng Turng ◽  
Xiang-Fang Peng
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Thermoplastic Polyurethane ◽  
Dynamic Mechanical Properties ◽  
Skin Layer ◽  
Tissue Engineering Scaffolds ◽  
Blowing Agents ◽  
Microcellular Injection Molding ◽  
Noticeable Reduction ◽  
Free Transport

In this study, a novel microcellular injection foaming method employing supercritical CO2 (scCO2) and water as co-blowing agents was developed to produce thermoplastic polyurethane (TPU) tissue engineering scaffolds with a uniform porous structure and no solid skin layer. Various characterization techniques were applied to investigate the cell morphology, crystallization behavior, and static and dynamic mechanical properties of solid molded samples, foamed samples using CO2 or water as a single blowing agent, and foamed samples using both CO2 and water as co-blowing agents. Compared with CO2 foamed scaffolds, scaffolds produced by the co-blowing method exhibit much more uniform cell morphologies without a noticeable reduction in mechanical properties. Moreover, these TPU scaffolds have almost no skin layer, which permits free transport of nutrients and waste throughout the samples, which is highly desirable in tissue engineering. The effect of these blowing agents on the shear viscosity of various samples is also reported.

Near-Field Electrospinning and Characterization of Biodegradable Small Diameter Vascular Grafts

2021 ◽  
Author(s):  
◽  
William King, III ◽  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Pore Size ◽  
Vascular Graft ◽  
Fiber Diameter ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Pore Sizes ◽  
Small Diameter Vascular Grafts

The ideal “off the shelf” tissue engineering, small-diameter (< 6 mm inner diameter (ID)) vascular graft hinges on designing a template that facilitates transmural ingrowth of capillaries to regenerate an endothelized neointimal surface. Previous traditionally electrospun (TES) approaches to create bioresorbable vascular grafts lack the pore sizes required to facilitate transmural capillary ingrowth required for successful in situ neovascular regeneration. Therefore, the ability to create scaffolds with program-specific architectures independent of fiber diameter via the relatively recent sub-technique of near-field electrospinning (NFES) represents a promising solution to create tissue engineering vascular grafts. These programmed large pore sizes are anticipated to promote in situ regeneration and improve the outcomes as well as the quality of life of patients with arterial disease. In this dissertation, we manufactured via NFES as well as characterized biodegradable polydioxanone (PDO) small-diameter vascular grafts. Chapter 1 introduces the need for off-the-shelf, small-diameter vascular grafts to facilitate in situ regeneration, the process and pore size limitations of TES vascular grafts, and the promising use of NFES to develop precisely tailored PDO vascular grafts. Chapter 2 describes the process of NFES and details the current progress in NFES of biomedical polymers as well as the major limitations that exist in the field. Chapters 3, 4, and 5 contain primary research exploring the creation of an NFES vascular graft scaffold and characterizing the mechanical as well as biological response of these scaffolds. Specifically, in Chapter 3 we demonstrate a NFES apparatus designed around a commercial 3D printer to write PDO microfibers. The processing parameters of air gap, polymer concentration, translational velocity, needle gauge, and applied voltage were characterized for their effects on PDO fiber diameter. The processing parameters of polymer concentration and translational fiber deposition velocity were further characterized for their effects on fiber crystallinity and individual fiber uniformity. The precision of fiber stacking via a 3D printer was qualitatively evaluated to inform the creation of 3D scaffolds to guide the alignment of human gingival fibroblasts. It was found that fiber diameters correlate positively with polymer concentration, applied voltage, and needle gauge and inversely correlate with translational velocity and air gap distance. Individual fiber diameter variability decreases, and crystallinity increases with increasing translational fiber deposition velocity. These data resulted in the creation of tailored PDO 3D scaffolds which guided the alignment of primary human fibroblast cells. Together, these results suggest that NFES of PDO can be scaled to create precise geometries with tailored fiber diameters for vascular graft scaffolds. In Chapter 4, we demonstrated a NFES device to semi-stably write PDO microfibers. The polymer spinneret was programmed to translate in a stacking grid pattern, which resulted in a scaffold with highly aligned grid fibers that were intercalated with low density, random fibers. As a consequence of this random switching process, increasing the grid dimensions resulted in both a lower density of fibers in the center of each grid in the scaffold as well as a lower density of “rebar-like” stacked fibers per unit area. These hybrid architecture scaffolds resulted in tailorable as well as greater surface pore sizes as given by scanning electron micrographs and effective object permeability as indicated by fluorescent microsphere filtration compared to TES scaffolds of the same fiber diameter. Furthermore, these programmable scaffolds resulted in tailorability in the characterized mechanical properties ultimate tensile strength, percent elongation, yield stress, yield elongation, and Young’s modulus independent of fiber diameter compared to the static TES scaffold characterization. Lastly, the innate immune response of neutrophil extracellular traps (NETs) was further attenuated on NFES scaffolds compared to TES scaffolds. These results suggest that this novel NFES scaffold architecture of PDO can be highly tailored as a function of programming for small diameter vascular graft scaffolds. In Chapter 5, we created two types of NFES PDO architectures, as small-diameter vascular graft scaffolds. The first architecture type consisted of a 200 x 200 µm and 500 x 500 µm grid geometry with random fiber infill produced from one set of processing parameters, while the second architecture consisted of aligned fibers written in a 45°/45° and 20°/70° offset from the long axis, both on a 4 mm diameter cylindrical mandrel. These vascular graft scaffolds were characterized for their effective object transit pore size, mechanical properties, and platelet-material interactions compared to TES scaffolds and Gore-Tex® vascular grafts. It was found that effective pore size, given by 9.9 and 97 µm microsphere filtration through the scaffold wall for NFES grafts, was significantly more permeable compared to TES grafts and Gore-Tex® vascular grafts. Furthermore, the characterized mechanical properties of ultimate tensile strength, percent elongation, suture retention, burst pressure, and Young’s modulus were all tailorable for NFES grafts, independent of fiber diameter, compared to TES graft characterization. Lastly, platelet adhesion was attenuated on large pore size NFES grafts compared to the TES grafts which approximated the low level of platelet adhesion measured on Gore-Tex® grafts, with all grafts showing minimal platelet activation given by P-selectin surface expression. Together, these results suggest a highly tailorable process for the creation of the next generation of small-diameter vascular grafts. Lastly, Chapter 6 expounds future considerations for continuing research in NFES technology, NFES for general tissue engineering, and NFES for vascular tissue engineering as well as gives final conclusions. Together, the finding of this dissertation indicated that NFES vascular grafts result in seamless, small diameter tubular scaffolds with programmable pore sizes on the magnitude anticipated to facilitate transmural endothelialization as well as programmable mechanical properties that approximate native values. Thus, this work represents the next step in developing bioinstructive designed scaffolds to facilitate in situ vascular regeneration to improve the outcomes as well as the quality of life of patients with arterial vascular disease.

Microscopic Methods for Characterization of Selected Surface Properties of Biodegradable, Nanofibrous Tissue Engineering Scaffolds

2017 ◽  
Vol 890 ◽  
pp. 213-216 ◽  
Author(s):  
Adrian Chlanda ◽  
Ewa Kijeńska ◽  
Wojciech Święszkowski
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Force Spectroscopy ◽  
Operating Mode ◽  
Tissue Engineering Scaffolds ◽  
Force Microscopy ◽  
Atomic Force

Biodegradable polymeric fibers with nanoand submicron diameters, produced by electrospinning can be used as scaffolds in tissue engineering. It is necessary to characterize their mechanical properties especially at the nanoscale. The Force Spectroscopy is suitable atomic force microscopy mode, which allows to probe mechanical properties of the material, such as: reduced Young's modulus, deformation, adhesion, and dissipation. If combined with standard operating mode: contact or semicontact, it will also provide advanced topographical analysis. In this paper we are presenting results of Force Spectroscopy characterization of two kinds of electrospun fibers: polycaprolactone and polycaprolactone with hydroxyapatite addition. The average calculated from Johnson-Kendall-Roberts theory Young's modulus was 4 ± 1 MPa for pure polymer mesh and 20 ± 3 MPa for composite mesh.

A Brief Review of the Modelling of the Time Dependent Mechanical Properties of Tissue Engineering Scaffolds

2010 ◽  
Vol 6 ◽  
pp. 19-33 ◽  
Author(s):  
N.K. Bawolin ◽  
W.J. Zhang ◽  
Xiong Biao Chen
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Treatment Process ◽  
Effective Properties ◽  
Critical Role ◽  
Time Dependent ◽  
Tissue Engineering Scaffolds ◽  
Wide Range ◽  
Scaffold Degradation

The functionality of tissue scaffolds in vivo plays a critical role in the treatment process. Due to the time dependent nature of the mechanical properties of the constituent phases of the scaffold, a wide range of mechanical property histories may be observed during the treatment process, possibly influencing outcomes. The critical nature of the mechanical properties in load bearing applications indicates a need for the simultaneous modelling of both scaffold degradation and tissue regeneration with time, and the resulting effective properties of the tissue engineering construct. To this end, a review of the literature is conducted to identify the various existing approaches to modelling scaffold degradation, tissue behavior, and the dependency of the two processes on one another.

Sign in / Sign up

Export Citation Format

Share Document