Computational Design and Optimization of Nerve Guidance Conduits for Improved Mechanical Properties and Permeability

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Shuo Zhang ◽  
Sanjairaj Vijayavenkataraman ◽  
Geng Liang Chong ◽  
Jerry Ying Hsi Fuh ◽  
Wen Feng Lu

Nerve guidance conduits (NGCs) are tubular tissue engineering scaffolds used for nerve regeneration. The poor mechanical properties and porosity have always compromised their performances for guiding and supporting axonal growth. Therefore, in order to improve the properties of NGCs, the computational design approach was adopted to investigate the effects of different NGC structural features on their various properties, and finally, design an ideal NGC with mechanical properties matching human nerves and high porosity and permeability. Three common NGC designs, namely hollow luminal, multichannel, and microgrooved, were chosen in this study. Simulations were conducted to study the mechanical properties and permeability. The results show that pore size is the most influential structural feature for NGC tensile modulus. Multichannel NGCs have higher mechanical strength but lower permeability compared to other designs. Square pores lead to higher permeability but lower mechanical strength than circular pores. The study finally selected an optimized hollow luminal NGC with a porosity of 71% and a tensile modulus of 8 MPa to achieve multiple design requirements. The use of computational design and optimization was shown to be promising in future NGC design and nerve tissue engineering research.

Nano LIFE ◽  
2012 ◽  
Vol 02 (04) ◽  
pp. 1230010 ◽  
Author(s):  
JEN-CHIEH WU ◽  
H. PETER LORENZ

Electrospinning is a process for generating micrometer or nanometer scale polymer fibers with large surface areas and high porosity. For tissue engineering research, the electrospinning technique provides a quick way to fabricate fibrous scaffolds with dimensions comparable to the extracellular matrix (ECM). A variety of materials can be used in the electrospinning process, including natural biomaterials as well as synthetic polymers. The natural biomaterials have advantages such as excellent biocompatibility and biodegradability, which can be more suitable for making biomimic scaffolds. In the last two decades, there have been growing numbers of studies of biomaterial fibrous scaffolds using the electrospinning process. In this review, we will discuss biomaterials in the electrospinning process and their applications in tissue engineering.


2019 ◽  
Vol 20 (20) ◽  
pp. 5061 ◽  
Author(s):  
Srikumar Krishnamoorthy ◽  
Behnam Noorani ◽  
Changxue Xu

Gelatin methacrylate (GelMA) has been gaining popularity in recent years as a photo-crosslinkable biomaterial widely used in a variety of bioprinting and tissue engineering applications. Several studies have established the effects of process-based and material-based parameters on the physical–mechanical properties and microstructure of GelMA hydrogels. However, the effect of encapsulated cells on the physical–mechanical properties and microstructure of GelMA hydrogels has not been fully understood. In this study, 3T3 fibroblasts were encapsulated at different cell densities within the GelMA hydrogels and incubated over 96 h. The effects of encapsulated cells were investigated in terms of mechanical properties (tensile modulus and strength), physical properties (swelling and degradation), and microstructure (pore size). Cell viability was also evaluated to confirm that most cells were alive during the incubation. It was found that with an increase in cell density, the mechanical properties decreased, while the degradation and the pore size increased.


2015 ◽  
Vol 3 (9) ◽  
pp. 1769-1778 ◽  
Author(s):  
Zhiyong Li ◽  
Yunlan Su ◽  
Baoquan Xie ◽  
Xianggui Liu ◽  
Xia Gao ◽  
...  

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.


2007 ◽  
Vol 330-332 ◽  
pp. 695-698 ◽  
Author(s):  
Dong Hua Guan ◽  
Chun Peng Huang ◽  
Ji Liu ◽  
Kun Tian ◽  
Lin Niu ◽  
...  

Poly 3-hydroxybutyrate (PHB) as a kind of polysaccharides has been proved promising for tissue engineering because of its biocompatibility and biodegradability. But its poor mechanical properties and hydrophilicity limit its application. In order to explore a new useful porch to improve the performance of PHB-based GTR membrane, membrane composed of nano-HA / PHB composite was manufactured through the air/jet electrospinning process which can potentially generate nanometer scale diameter fibers and enlarge surface area of materials while maintaining high porosity. Successively, the biomineralization behavior of the membrane in supersaturated calcification solution (SCS) was studied. The Results of this investigation show that the successfully manufactured porous nano-HA/PHB membrane has high activity in SCS and its ability of inducing the formation of mineral crystal in vitro than that of the unfilled PHB membrane. It can be concluded that the addition of nano-HA and the novel technology could improve the performance of the PHB-based GTR membrane.


2007 ◽  
Vol 7 (12) ◽  
pp. 4595-4603 ◽  
Author(s):  
R. Murugan ◽  
Z. M. Huang ◽  
F. Yang ◽  
S. Ramakrishna

Scaffold plays a critical role in tissue engineering where it provides necessary structural support for the cells to accommodate and to guide their growth in the three dimensional space into a specific tissue. Therefore, engineering scaffolds favorable for cell/tissue growth is of great importance and a pre-requisite for scaffold-based tissue engineering. Electrospinning is a versatile method that has been recently adapted in engineering nano-fibrous scaffolds that mimic the structural features of biological extracellular matrix (ECM). It offers many advantages over conventional scaffold methodologies, for example, capable of producing ultra-fine fibers with high porosity, high spatial orientation, high aspect ratio, and high surface area, which are highly required for the initial cell attachment, tissue formation, and continued function. Considering these astonishing merits, this article emphasis on nano-fibrous scaffold engineering by electrospinning.


Author(s):  
M. T. Arafat ◽  
M. M. Savalani ◽  
I. Gibson

Scaffold-based tissue engineering research aims to aid in the repair and regeneration of bone defects. Scaffolds act as a basis for carrying cells or therapeutic agents for regenerative therapies. To achieve this, the scaffold should have appropriate osteoconductive, osteoinductive and biodegradable properties. To date, such structures have only been used with some success in low-load bearing applications, despite the large variety of biomaterials and fabrication techniques explored in the last two decades. Previous studies have illustrated the suitability of the Fused Deposition Modelling (FDM) process in fabricating PCL-20% β-TCP scaffolds for low-load bearing bone tissue engineering applications. This paper aims to demonstrate the possibility of increasing the mechanical properties of such scaffolds by introducing a through-hole. In addition, it is conjectured that such through-holes may also become useful for the channeling or storage of nutrients. A number of scaffolds with through-holes of various sizes were fabricated in order to study the effect of the through-hole diameter on the modulus (stiffness) of the complete scaffold. It was observed that the stiffness of the scaffolds varies with the diameter of the through-hole. After a certain through-hole diameter threshold the stiffness of the scaffold begins to increase above that of the original scaffold. An improvement of approximately 37% was observed in the PCL-20% β-TCP scaffolds. Also, it was noted that the threshold value for the through-hole diameter depends on the spacing of the adjacent filaments of the scaffolds.


2013 ◽  
Vol 13 (01) ◽  
pp. 1350020 ◽  
Author(s):  
Y. S. LIU ◽  
Q. L. HUANG ◽  
Q. L. FENG ◽  
N. M. HU ◽  
O. ALBERT

In order to improve the mechanical properties of scaffolds for bone tissue engineering, the present study aims to bring calcium carbonate (CaCO3) with signaling molecules, namely pearl powder, into poly(L-lactic acid) (PLLA). PLLA/aragonite and PLLA/vaterite scaffolds were successfully fabricated by the freeze-drying method. Both composite scaffolds had a similar porous structure but a different saturated content of pearl powders. For both scaffolds, the porosity decreases and yield strength increases as pearl powder content increases. Introducing pearl powders into PLLA can improve the mechanical properties of the scaffolds. The porous structure plays a crucial role in the yield strength of pure PLLA scaffolds, whereas the yield strength of PLLA/pearl powder scaffolds mostly relies on pearl powder content.


2019 ◽  
Vol 34 (6) ◽  
pp. 442-452
Author(s):  
Meiling Zhong ◽  
Jinsheng Li ◽  
Aoqi Tang ◽  
Qi Zhang ◽  
Dehui Ji ◽  
...  

Bacterial cellulose holds great promise for tissue engineering, but its application is greatly limited due to the lack of large pores and poor cell affinity. In this study, macroporous bacterial cellulose was fabricated through the dissolution of gelatin microspheres, which were incorporated with bacterial cellulose during bacterial cellulose fabrication. Then, gelatin was immobilized onto bacterial cellulose surface via procyanidins crosslinking. The results confirmed that the scaffolds possessed interconnected macroporous structure, high porosity, good water uptake ability, and good mechanical properties. The results of evaluation of cells showed that cells migrated to the inner of macroporous affinitive bacterial cellulose and displayed better spreading as well as proliferation than that on pure bacterial cellulose surfaces. The macroporous affinitive bacterial cellulose show potential as a scaffold for tissue engineering.


Author(s):  
Ning Zhu ◽  
Xiong Biao Chen ◽  
Dean Chapman

In nerve tissue engineering, scaffolds act as carriers for cells and biochemical factors and as constructs providing appropriate mechanical conditions. During nerve regeneration, new tissue grows into the scaffolds, which degrade gradually. To optimize this process, researchers must study and analyze various morphological and structural features of the scaffolds, the ingrowth of nerve tissue, and scaffold degradation. Therefore, visualization of the scaffolds as well as the generated nerve tissue is essential, yet challenging Visualization techniques currently used in nerve tissue engineering include electron microscopy, confocal laser scanning microscopy (CLSM), and micro-computed tomography (micro-CT or μCT). Synchrotron-based micro-CT (SRμCT) is an emerging and promising technique, drawing considerable recent attention. Here, we review typical applications of these visualization techniques in nerve tissue engineering. The promise, feasibility, and challenges of SRμCT as a visualization technique applied to nerve tissue engineering are also discussed.


RSC Advances ◽  
2018 ◽  
Vol 8 (23) ◽  
pp. 12933-12943 ◽  
Author(s):  
Yuan Kang ◽  
Peng Chen ◽  
Xuetao Shi ◽  
Guangcheng Zhang ◽  
Chaoli Wang

For tissue engineering applications, it is essential that biodegradable scaffolds have accessible mechanical properties, high porosity, and good biocompatibility to support the formation of new tissues.


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