A Structural Model for the Flexural Mechanics of Nonwoven Tissue Engineering Scaffolds

2006 ◽  
Vol 128 (4) ◽  
pp. 610-622 ◽  
Author(s):  
George C. Engelmayr ◽  
Michael S. Sacks
Keyword(s):  
Tissue Engineering ◽  
Soft Tissues ◽  
Structural Model ◽  
Fiber Diameter ◽  
Polyglycolic Acid ◽  
Mechanical Effect ◽  
Effective Stiffness ◽  
Tissue Formation ◽  
Functional Requirements ◽  
Tissue Engineering Scaffolds

The development of methods to predict the strength and stiffness of biomaterials used in tissue engineering is critical for load-bearing applications in which the essential functional requirements are primarily mechanical. We previously quantified changes in the effective stiffness (E) of needled nonwoven polyglycolic acid (PGA) and poly-L-lactic acid (PLLA) scaffolds due to tissue formation and scaffold degradation under three-point bending. Toward predicting these changes, we present a structural model for E of a needled nonwoven scaffold in flexure. The model accounted for the number and orientation of fibers within a representative volume element of the scaffold demarcated by the needling process. The spring-like effective stiffness of the curved fibers was calculated using the sinusoidal fiber shapes. Structural and mechanical properties of PGA and PLLA fibers and PGA, PLLA, and 50:50 PGA/PLLA scaffolds were measured and compared with model predictions. To verify the general predictive capability, the predicted dependence of E on fiber diameter was compared with experimental measurements. Needled nonwoven scaffolds were found to exhibit distinct preferred (PD) and cross-preferred (XD) fiber directions, with an E ratio (PD/XD) of ∼3:1. The good agreement between the predicted and experimental dependence of E on fiber diameter (R2=0.987) suggests that the structural model can be used to design scaffolds with E values more similar to native soft tissues. A comparison with previous results for cell-seeded scaffolds (Engelmayr, G. C., Jr., et al., 2005, Biomaterials, 26(2), pp. 175–187) suggests, for the first time, that the primary mechanical effect of collagen deposition is an increase in the number of fiber-fiber bond points yielding effectively stiffer scaffold fibers. This finding indicated that the effects of tissue deposition on needled nonwoven scaffold mechanics do not follow a rule-of-mixtures behavior. These important results underscore the need for structural approaches in modeling the effects of engineered tissue formation on nonwoven scaffolds, and their potential utility in scaffold design.

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.

Assessment of polyglycolic acid mesh and bioactive glass for soft-tissue engineering scaffolds

Biomaterials ◽  
2004 ◽  
Vol 25 (27) ◽  
pp. 5857-5866 ◽  
Author(s):  
Richard M. Day ◽  
Aldo R. Boccaccini ◽  
Sandra Shurey ◽  
Judith A. Roether ◽  
Alastair Forbes ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Soft Tissue ◽  
Bioactive Glass ◽  
Polyglycolic Acid ◽  
Tissue Engineering Scaffolds ◽  
Polyglycolic Acid Mesh ◽  
Soft Tissue Engineering

scholarly journals Full cell infiltration and thick tissue formation in vivo in tailored electrospun scaffolds

2020 ◽  
Author(s):  
Jip Zonderland ◽  
Silvia Rezzola ◽  
David Gomes ◽  
Sandra Camarero Espinosa ◽  
Ana Henriques Ferreira Lourenço ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Fiber Diameter ◽  
Cell Infiltration ◽  
Tissue Formation ◽  
Cell Seeding ◽  
Subcutaneous Implantation ◽  
Electrospun Scaffolds ◽  
Limited Depth

AbstractElectrospun (ESP) scaffolds are a promising type of tissue engineering constructs for large defects with limited depth. To form new functional tissue, the scaffolds need to be infiltrated with cells, which will deposit extracellular matrix. However, due to dense fiber packing and small pores, cell and tissue infiltration of ESP scaffolds is limited. Here, we combine two established methods, increasing fiber diameter and co-spinning sacrificial fibers, to create a porous ESP scaffold that allows robust tissue infiltration. Full cell infiltration across 2 mm thick scaffolds is seen 3 weeks after subcutaneous implantation in rats. After 6 weeks, the ESP scaffolds are almost fully filled with de novo tissue. Cell infiltration and tissue formation in vivo in this thickness has not been previously achieved. In addition, we propose a novel method for in vitro cell seeding to improve cell infiltration and a model to study 3D migration through a fibrous mesh. This easy approach to facilitate cell infiltration further improves previous efforts and could greatly aid tissue engineering approaches utilizing ESP scaffolds.Statement of significanceElectrospinning creates highly porous scaffolds with nano- to micrometer sized fibers and are a promising candidate for a variety of tissue engineering applications. However, smaller fibers also create small pores which are difficult for cells to penetrate, restricting cells to the top layers of the scaffolds. Here, we have improved the cell infiltration by optimizing fiber diameter and by co-spinning a sacrificial polymer. We developed novel culture technique that can be used to improve cell seeding and to study cytokine driven 3D migration through fibrous meshes. After subcutaneous implantation, infiltration of tissue and cells was observed up to throughout up to 2 mm thick scaffolds. This depth of infiltration in vivo had not yet been reported for electrospun scaffolds. The scaffolds we present here can be used for in vitro studies of migration, and for tissue engineering in defects with a large surface area and limited depth.

scholarly journals Effect of Relative Humidity on the Electrospinning Performance of Regenerated Silk Solution

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2479
Author(s):  
Bo Kyung Park ◽  
In Chul Um
Keyword(s):  
Tissue Engineering ◽  
Fourier Transform ◽  
Relative Humidity ◽  
Biomedical Applications ◽  
Molecular Conformation ◽  
Fiber Diameter ◽  
Tissue Engineering Scaffolds ◽  
Formic Acid Solution ◽  
Good Biocompatibility ◽  
Β Sheet

Recently, the electrospun silk web has been intensively studied in terms of its biomedical applications, including tissue engineering scaffolds, due to its good biocompatibility, cytocompatibility, and biodegradability. In this study, the effect of relative humidity (RH) conditions on the morphology of electrospun silk fiber and the electrospinning production rate of silk solution was examined. In addition, the effect of RH on the molecular conformation of electrospun silk web was examined using Fourier transform infrared (FTIR) spectroscopy. As RH was increased, the maximum electrospinning rate of silk solution and fiber diameter of the resultant electrospun silk web were decreased. When RH was increased to 60%, some beads were observed, which showed that the electrospinnability of silk formic acid solution deteriorated with an increase in RH. The FTIR results showed that electrospun silk web was partially β-sheet crystallized and RH did not affect the molecular conformation of silk.

Scaffolds for Tissue Engineering

MRS Bulletin ◽  
2003 ◽  
Vol 28 (4) ◽  
pp. 301-306 ◽  
Author(s):  
Jeffrey M. Karp ◽  
Paul D. Dalton ◽  
Molly S. Shoichet
Keyword(s):  
Tissue Engineering ◽  
Soft Tissues ◽  
High Water ◽  
Nerve Fibers ◽  
Nerve Tissue ◽  
Tissue Type ◽  
High Water Content ◽  
Tissue Engineering Scaffolds ◽  
High Degree ◽  
Interconnected Pores

AbstractDevices for tissue engineering comprise scaffolds with the appropriate chemistry and architecture to promote cell infiltration and colonization. The scaffold is designed with biology in mind, and thus the architecture and chemistry differ according to tissue type. In this review, we focus on scaffolds for two tissue types—bone and nervous tissue—and describe different approaches used to create them. The appropriate scaffold for a hard tissue such as bone has a high degree of interconnected macroporosity and allows the rapid invasion of cells while maintaining a rigid structure. Several approaches are described for constructing tissue-engineering scaffolds for bone. The appropriate scaffold for soft tissues like nerve fibers (e.g., axons, which conduct nerve impulses) also has a high degree of interconnected pores; however, the pores may require orientation and may be smaller. Homogeneous, high-water-content hydrogels with mechanical properties that match the soft nerve tissue are commonly used as a scaffold, and the methods used to make these are reviewed.

Tissue Engineering Scaffolds for Repairing Soft Tissues

2016 ◽  
pp. 301-330
Author(s):  
Andrés Díaz Lantada ◽  
Enrique Colomer Mayola ◽  
Sebastien Deschamps ◽  
Beatriz Pareja Sánchez ◽  
Josefa Predestinación García Ruíz ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Soft Tissues ◽  
Tissue Engineering Scaffolds

scholarly journals Liquid-Assisted Electrospinning Three-Dimensional Polyacrylonitrile Nanofiber Crosslinked with Chitosan

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xiaoli Yang ◽  
Xue Chen ◽  
Jingyi Zhao ◽  
Wenlu Lv ◽  
Qilu Wu ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Wound Healing ◽  
Pore Structure ◽  
Antibacterial Effect ◽  
Fiber Diameter ◽  
Three Dimensional ◽  
Special Structure ◽  
Tissue Engineering Scaffolds ◽  
Antimicrobial Effectiveness ◽  
Pan Nanofiber

Electrospinning has become a popular nanotechnology for the fabrication of tissue engineering scaffolds, which can precisely regulate fiber diameter and microstructure. Herein, we have prepared a three-dimensional polyacrylonitrile (PAN) nanofiber by liquid-assisted electrospinning. The spacing between PAN nanofibers can reach to 15-20 μm, as the uniform internally connected pore structure can be formed, through the regulation of parameters. Furthermore, the chitosan attached to the as-prepared nanofibers gives the material antibacterial effect and increases its biocompatibility. Meanwhile, the special structure of chitosan also provides the possibility for further loading drugs in dressings in the future. This newly developed nanocomposite seems to be highly suitable for wound healing due to its unique properties of biodegradability, biocompatibility, and antimicrobial effectiveness.

Novel tissue engineering scaffolds as wound dressings loaded with Alkannins/Shikonins as active ingredients

2019 ◽  
Author(s):  
AS Arampatzis ◽  
K Theodoridis ◽  
E Aggelidou ◽  
KN Kontogiannopoulos ◽  
I Tsivintzelis ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Wound Dressings ◽  
Active Ingredients ◽  
Tissue Engineering Scaffolds

HYDROXYAPATITE, ALGINATE, AND CHITOSAN FOR BONE SCAFFOLDS: SPECTROSCOPY STUDY

2016 ◽  
Vol 19 (2) ◽  
pp. 93-100
Author(s):  
Lalita El Milla
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Functional Groups ◽  
Bone Growth ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Tissue Engineering Scaffolds ◽  
Hydroxyapatite Powder ◽  
Materials Used

Scaffolds is three dimensional structure that serves as a framework for bone growth. Natural materials are often used in synthesis of bone tissue engineering scaffolds with respect to compliance with the content of the human body. Among the materials used to make scafffold was hydroxyapatite, alginate and chitosan. Hydroxyapatite powder obtained by mixing phosphoric acid and calcium hydroxide, alginate powders extracted from brown algae and chitosan powder acetylated from crab. The purpose of this study was to examine the functional groups of hydroxyapatite, alginate and chitosan. The method used in this study was laboratory experimental using Fourier Transform Infrared (FTIR) spectroscopy for hydroxyapatite, alginate and chitosan powders. The results indicated the presence of functional groups PO43-, O-H and CO32- in hydroxyapatite. In alginate there were O-H, C=O, COOH and C-O-C functional groups, whereas in chitosan there were O-H, N-H, C=O, C-N, and C-O-C. It was concluded that the third material containing functional groups as found in humans that correspond to the scaffolds material in bone tissue engineering.

Sign in / Sign up

Export Citation Format

Share Document