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Evaluation of PCL/Chitosan/Nanohydroxyapatite/Tetracycline Composite Scaffolds for Bone Tissue Engineering
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Rashid Bin Mad Jin, Naznin Sultana, Chin Fhong Soon, Ahmad Fauzi Ismail
In this chapter, PCL/chitosan-based scaffolds were fabricated for bone tissue engineering applications. Normal human osteoblast cell studies will provide insight into the performance of the scaffolds as an implant for bone regeneration. The osteoblast is a fully differentiated cell that is responsible for the synthesis and mineralization of bone during bone formation and remodeling. It can produce many cell products such as the enzymes alkaline phosphate and collagenase, growth factors, hormones and many others (Velasco et al. 2015). VEGF growth factors were used as their “enhanced vascularization” provides abundant osteoprogenitor cells to the defect site along with a direct stimulating effect on the osteoblast migration and differentiation, leading to higher bone deposition” (Bose et al. 2012).
Application of chitosan in dentistry—a review
Published in J. Belinha, R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, João Manuel, R.S. Tavares, Biodental Engineering V, 2019
J.M.S. Gomes, J. Belinha, R.M. Natal Jorge
The structural scaffold of our body is the skeleton, and the bones that constitute it are key elements for locomotion, antigravity support, life-sustaining functions, and protection of viscera (Graber, Vanarsdall, Vig, & Huang, 2017; Walsh, 2018). Bone tissue is a specialized form of highly vascularized connective tissue which main components are collagen and calcium phosphate (Q. Li, Ma, & Gao, 2015). Bone is divided in cortical and trabecular tissues. The first is a hard and outer layer that surrounds the marrow space, while the latter resembles a honeycomb-like network of interspersed plates and rods, occupying a larger surface area (Clarke, 2008; Walsh, 2018). The cellular component of the bone includes osteoblasts, osteoclasts and osteocytes, each one of them with specific functions. Osteoblasts are responsible for forming bone by synthesizing the organic matrix, which is mainly type I collagen, and for giving bone resistance and tensile forces. On the other hand, osteoclasts, that derive from the monocyte/macrophage cell line, locally degrade the bone matrix during the resorption process. Osteocytes are localized between the bone matrix and are terminally differentiated osteoblasts that convert mechanical loading into biomechanical stimulus (Feng & McDonald, 2011).
Mechanostimulation in Bone and Tendon Tissue Engineering
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Samuel B. VanGordon, Warren Yates, Vassilios I. Sikavitsas
Bone formation and remodeling are considered sensitive to mechanical forces exerted on bone tissue [10,16,20,21]. Compression and tension is created from the loading and unloading of bone. Loading results in bone deformation that leads to pressure differences in the interstitial fluid leading to flow. Coupled with vascular transport there is movement of fluid through the canaliculi and lacunae of bone [22–27]. These compressions, tensions, and fluid movements translate forces onto the major bone cells (i.e., osteoblasts and osteocytes). The stresses and strains cause the deformation of the cell bodies [28,29]. How mechanical stimuli are translated into biochemical pathways is not fully understood. Some hypothesized mechanisms of mechanical signal conversion involve membrane ion channels [30–37], focal adhesions [36,38–44], intracellular junctions [45–52], and cilia [53–57]. Mechanical stimulation seems to regulate osteoblast function, proliferation and differentiation [58]. Interstitial flow plays a major role in bone homeostasis [25] and has been reported to enhance in vitro osteogenesis [25,59,60]. It is proposed that engineered bone grafts, if adequately perfused, can lead to enhanced cell stimulation, nutrient transportation, and bone regeneration [25].
Influence of strontium dopant on bioactivity and osteoblast activity of spray pyrolyzed strontium-doped mesoporous bioactive glasses.
Published in Journal of Asian Ceramic Societies, 2021
Yu-Chieh Fei, Liu-Gu Chen, Chao-Kuang Kuo, Yu-Jen Chou
To deal with the above problems, in this work we aimed to synthesize Sr-doped MBG specimens using the spray pyrolysis technique. The technique provides advantages of fast fabrication, rapid calcination, and continuous process as compared to glass melting and sol-gel method [21,22]. Preparation of undoped and 1, 5, 10 mol% Sr-doped MBG specimens were carried out, while the phase information, particle morphology, mesoporous structure, and specific surface area were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) method, respectively. Meanwhile, evaluation of in vitro bioactivity tests were carried out using both XRD and Fourier transform infrared spectroscopy (FTIR). The osteoblast activity was examined employing alkaline phosphatase (ALP) assay. Finally, the formation mechanisms of all MBG specimens and their related properties were discussed.
Optimization of electrospinning process & parameters for producing defect-free chitosan/polyethylene oxide nanofibers for bone tissue engineering
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Yogendra Pratap Singh, Sudip Dasgupta, Suprabha Nayar, Rakesh Bhaskar
ALP assay was carried out to confirm the alkaline phosphatase (ALP) activity which is a characteristic feature of osteoblast phenotype. It is a well-known enzyme secreted by mature osteoblast that catalyzes the hydrolysis of phosphate esters at an alkaline pH [30]. It has also been evident that it plays an active role in bone matrix mineralization process initiated by mature osteoblast. The results of the ALP assay are as shown in Figure 16. Expression of ALP was clearly evident in Figure 16 (b1) and 16 (b2) from dark red spot in micrographs of MG 63 cells on prepared chitosan scaffolds after 7 and 14 days of culture along with cells cultured on TCP used as control in Figure 16 (a1) and 16 (a2). From quantitative analysis in Figure 16 (c), it can be seen that keeping up with the same trend with MG 63 seeded tissue culture plate (TCP), ALP activity increased from 7 days to 14 days culture period on electrospun chitosan/PEO (50:50) scaffold. Since ALP is a late stage differentiation marker for osteoblast cells, expression of ALP is an indication of transformation of MG 63 cultured cells onto CS scaffolds into mature osteoblast after 7 and 14 days of cell culture. This increase in ALP activity implies that prepared CS scaffold supports active bone formation on its surface and are suitable for use in bone regeneration applications.
The analogies between human development and additive manufacture: Expanding the definition of design
Published in Cogent Engineering, 2019
L. E. J. Thomas-Seale, J. C. Kirkman-Brown, S. Kanagalingam, M. M. Attallah, D. M. Espino, D. E. T. Shepherd
Bone is a highly dynamic tissue; bone modelling during growth and remodelling upon maturity results in the constant regeneration of the skeleton (Manolagas, 2000). Bone remodelling is the renewal of bone to maintain strength and homeostasis, it is not limited to the mature adult, but begins in the foetus and continues until death (Clarke, 2008). Remodelling has four distinct stages: activation, resorption, reversal and formation (Clarke, 2008). The cellular contributors to these processes are osteoblasts, osteoclasts and osteocytes. Osteoblasts are differentiated from mesenchymal stem cells and contribute to the formation of bone matrix, whereas osteoclasts differentiated from the monocyte/macrophage lineage, reabsorb the bone (Hadjidakis & Androulakis, 2006; Manolagas, 2000). The osteocyte is differentiated from the osteoblast and becomes embedded in the bone matrix. Osteocytes, which make up 90–95% of all adult bone cells, have many functions, one of which is as a mechanosensitive cell (Bonewald, 2011). Effectively osteoclasts, osteoblasts and osteocytes coordinate, at a cellular level, the tissue response to the external environment. This process not only operates across scales, but also differs between spatial locations.