Papers by Keyword: Tissue Engineering

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Authors: Criseida Ruiz-Aguilar, E.A. Aguilar-Reyes, Ana Edith Higareda-Mendoza, C.A. León-Patiño
Abstract: Bone tissue engineering is an excellent alternative to reduce bone disorders and conditions, by inducing new functional bone regeneration starting from the synthesis of the biomaterials and then the combination of cell and factor therapy. In the present contribution, the scaffolds were made with a ratio of 80 wt.% of β-TCP and 20 wt. % of phosphate-based bioglass, in addition the phosphate-based bioglass was reinforced with zirconia in different amounts (0, 0.5 and 1.0 mol%) with the aim to reduce the dissolution rate, improve the osteoconduction and the osteogenesis of the bone tissue. The results obtained by μCT of the scaffolds containing zirconia showed a wide pore size distribution between 1.5 and 303 μm. AlamarBlue assays showed that the cell proliferation of MC3T3-E1 preosteoblasts scaffolds were sixfold increase in relation to the number of the initial cells. FE-SEM helped to observe the cauliflower structure of HA and DRX showed that crystalline phases formed after heat treatment were (NaCaPO4 and NaZr5PO4) owing both to the crystallization and combination of the bioglass and β-TCP .
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Authors: Nader Nezafati, F. Moztarzadeh, Masoud Mozafari
Abstract: Basic drawbacks of calcium phosphate cements (CPCs) are the brittleness and low strength behavior which prohibit their use in many stress-bearing locations, unsupported defects, or reconstruction of thin bones. Recently, to solve these problems, researchers investigated the incorporation of fibers into CPCs to improve their strength. In the present study, various amounts of a highly bioactive glass fiber were incorporated into calcium phosphate bone cement. The obtained results showed that the compressive strength of the set cements without any fibers optimally increased by further addition of the fiber phase. Also, both the work-of-fracture and elastic modulus of the cement were considerably increased after applying the fibers in the cement composition. Herein, with the aim of using the reinforced-CPC as appropriate bone filler, the prepared sample was evaluated in vitro using simulated body fluid (SBF) and osteoblast cells. The samples showed significant enhancement in bioactivity within few days of immersion in SBF solution. Also, in vitro experiments with osteoblast cells indicated an appropriate penetration of the cells, and also the continuous increase in cell aggregation on the samples during the incubation time demonstrated the ability of the reinforced-CPC to support cell growth. Therefore, we concluded that this filler and strong reinforced-CPC may be beneficial to be used as bone fillers in surgical sites that are not freely accessible by open surgery or when using minimally invasive techniques.
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Authors: Hui Rong Xu, Shao Chun Sui, Xiao Hong Wang, Yong Nian Yan, Ren Ji Zhang
Abstract: Bioreactor technology is a branched research area of tissue engineering. Dynamic culture environment mimicking in vivo pulsatile conditions could be achieved by bioreactor otherwise might not through static cultures. In this paper, we present a new type of pulse bioreactor which can provide arbitrary and easily adjustable circulatory flow conditions of 0 - 0.2 MPa pressure. The pulse amplitude range was 0 - 7%. The pulse frequency can be adjusted between 0 and 80 times/min. In addition, the new type of pulse bioreactor can be sterilized and dismantled easily. This bioreactor has been used in dynamic culture of assembled adipose derived stem cells (ADSCs) and shown promise in tissue engineering.
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Authors: Ning Zhu, Xiong Biao Chen, Dean Chapman
Abstract: 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.
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Authors: Larry L. Hench, Julia M. Polak
Abstract: Historically the function of biomaterials has been to replace diseased, damaged and aged tissues. First generation biomaterials, including bio ceramics, were selected to be as inert as possible in order to minimize the thickness of interfacial scar tissue. Bioactive glasses provided an alternative from the 1970’s onward; second generation bioactive bonding of implants with tissues and no interfacial scar tissue. This chapter reviews the discovery that controlled release of biologically active Ca and Si ions from bioactive glasses leads to the up-regulation and activation of seven families of genes in osteoprogenitor cells that give rise to rapid bone regeneration. This finding offers the possibility of creating a new generation of gene activating bioceramics designed specially for tissue engineering and in situ regeneration of tissues.
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Authors: Guo Ping Chen, Takashi Ushida, Tetsuya Tateishi
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Authors: Zheng Guo, Jin Jing Chen, Pei Hua Zhang
Abstract: A tubal knitted scaffold fabricated from poly(lactic acid) (PLA) yarns was given in this work. The performance of the scaffold during degradation in vitro and the morphology of the scaffold with cells (monkey dermal fibroblasts) were examined. The scaffold fabricated from poly(glycolic acid) (PGA) yarns was manufactured as the control. Results showed that the PLA scaffold could keep much more tensile strength during degradation in vitro, compared with the PGA scaffold. However, cell attachment and proliferation on the PGA scaffold were better than on the PLA scaffold.
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Authors: S. Singare, Shou Yan Zhong, Zhen Zhong Sun
Abstract: In this paper, the authors describe a rapid prototyping method to produce vascularized tissue such as liver scaffold for tissue engineering applications. A scaffold with an interconnected channel was designed using a CAD environment. The data were transferred to a Polyjet 3D Printing machine (Eden 250, Object, Israel) to generate the models. Based on the 3D Printing model, a PDMS (polydimethyl-silicone) mould was created which can be used to cast the biodegradable material. The advantages and limitations of Rapid Prototyping (RP) techniques as well as the future direction of RP development in tissue engineering scaffold fabrication were reviewed.
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Authors: Shahrokh Shahi, Soheil Mohammadi
Abstract: Some of the heart valve diseases can be treated by surgical replacement with either a mechanical or bioprosthetic heart valve (BHV). Recently, tissue-engineered heart valves (TEHVs) have been proposed to be the ultimate solution for treating valvular heart disease. In order to improve the durability and design of artificial heart valves, recent studies have focused on quantifying the biomechanical interaction between the organ, tissue, and cellular –level components in native heart valves. Such data is considered fundamental to designing improved BHVs. Mechanical communication from the larger scales affects active biomechanical processes. For instance any organ-scale motion deforms the tissue, which in turn deforms the interstitial cells (ICs). Therefore, a multiscale solution is required to study the behavior of human aortic valve and to predict local cell deformations. The proposed multiscale finite element approach takes into account large deformations and nonlinear anisotropic hyperelastic material models. In this simulation, the organ scale motion is computed, from which the tissue scale deformation will be extracted. Similarly, the tissue deformation will be transformed into the cell scale. Finally, each simulation is verified against a number of experimental measures.
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