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Craniofacial Regeneration—Bone
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Laura Guadalupe Hernandez, Lucia Pérez Sánchez, Rafael Hernández González, Janeth Serrano-Bello
Artificial bone can be created from ceramics such as calcium phosphates, bioglass and calcium sulfate that are biologically active depending on solubility in the physiological environment. The varying nature of this graft material (porosity, geometries, differing solubilities and densities) will determine the resorption of calcium phosphate-based graft materials, bioceramics are neither osteogenic nor osteoinductive, but work by creating an osteoconductive scaffold to promote osteosynthesis. Today there are four main types of bioceramics available: calcium sulfate, calcium phosphate, tricalcium phosphate and coralline hydroxyapatite; composite bioceramics use a combination of these types to provide materials with improved properties (Kumar et al. 2013; Martin and Bettencourt 2018; Fillingham and Jacobs 2016).
Bio-Ceramics for Tissue Engineering
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Hasan Zuhudi Abdullah, Te Chuan Lee, Maizlinda Izwana Idris, Mohamad Ali Selimin
Calcium phosphate (CaP) has been used widely in biomedical applications due to its capability in mimicking the properties of natural bone (Table 8.4). It has been used in the formation of artificial bone (bone-graft) or as a bioactive coating on other biomaterials especially those made from bioinert metals for orthopaedic as well as orthodontic applications (Legeros et al. 2009). CaP can be observed naturally in biological systems. CaP has been synthesized and used to manufacture various forms of implants, as well as for solid and porous coating on other implants. It is necessary to mention that different phases of CaP exhibit different solubility coefficients and these are dependent on temperature, pH, and environmental composition (Shadanbaz and Dias 2012).
Treatment Planning for Small Animals
Published in George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos, Handbook of Small Animal Imaging, 2018
For Monte Carlo simulations in MV photons, commonly only four media are assigned in most studies (air, lung, soft tissue, and a single bone type, usually cortical bone). In recent work from Stanford University (Zhou et al. 2009) focused mostly on human geometries, the researchers advocated using 47 different artificial bone types; the composition of these is generated by realizing, for example, that the relative weight fraction of Ca and P correlates well with bone density in bone tissues (Figure 20.11). The 47 bone types were needed to limit errors in calculated terma to 2%. In a more recent study from the same group (Bazalova and Graves 2011), the influence of tissue assignment on Monte Carlo dose calculations was studied in detail for different radiation sources: kV x-ray units of 120 kV (2.5 mm Al), 225 kV (4 mm Al), 225 kV (0.5 mm Cu), 320 kV (1.5 mm Pb, 5 mm Sn, 1 mm Cu, 4 mm Al), and a brachytherapy 192Ir source (the information in brackets is the added filtration). The authors point out that there is no clear relationship between absorbed dose in tissue and mass density of the tissues for photon energies ≤ 225 kV. In other words, also information on effective atomic number is needed to achieve accurate dose calculations.
Synergies of accelerating differentiation of bone marrow mesenchymal stem cells induced by low intensity pulsed ultrasound, osteogenic and endothelial inductive agent
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Ruixin He, Junlin Chen, Jingwei Jiang, Baoru Liu, Dandan Liang, Weichen Zhou, Wenzhi Chen, Yan Wang
Large size bone defects, which can be caused by trauma and tumour resection, etc. affect millions of people. Treatment methods for bone defects can be categorized as autograft, allograft and xenograft [1]. However, all these methods have some disadvantages [2]. Therefore, researchers began to pay attention to the artificial bone as a substitute [3,4]. However, artificial bone has poor mechanical properties and conductivity and a single function [5], unlike the properties (e.g. mechanical strength and microstructure) and functions of natural bones. The lack of blood vessels in engineered tissues can lead to spatiotemporal gradients in oxygen and nutrients, accumulation of waste products and negative biological events at the core of the scaffold [6]. Therefore, the construction of stable blood vessels is a fundamental challenge for tissue engineering in regenerative medicine [7]. Recently, many strategies have been applied to enhance the establishment of vascularization within engineered bones, such as directing cell behavior through growth factor delivery [8], applying co-culturing systems [9], mechanical stimulation [10], microfabrication techniques with biomaterials [11] and 3D printing [12]. However, challenges remain due to the inability to reproduce an engineered bone replacement that truly mimics natural bone with well-formed and stable blood vessels [1]. Therefore, it is necessary to find a new scenario for constructing vascularized tissue-engineered bone.
A novel strategy for in vivo angiogenesis and osteogenesis: magnetic micro-movement in a bone scaffold
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Cong Luo, Xiaolan Yang, Ming Li, Hua Huang, Quan Kang, Xiaobo Zhang, Hui Hui, Xin Zhang, Chaode Cen, Yujia Luo, Lina Xie, Changxuan Wang, Tongchuan He, Dianming Jiang, Tingyu Li, Hong An
Based on the above theory, we proposed the application of an in vitro non-invasive oscillating magnetic field and static magnetic field to drive the micro-movement of magnetic gene-loaded microspheres inside an artificial bone scaffold to promote the release of plasmid genes from microspheres for transfection of surrounding cells. The in vitro release and local enrichment of the plasmid in vascular endothelial growth factor (VEGF) magnetic microspheres was observed in the presence of an external magnetic field (oscillating magnetic field and static magnetic field). Promotion of the in vivo vascularization and osteogenesis of the artificial bone was also observed. The superparamagnetic chitosan pDsVEGF165-green-N1 gelatin microspheres (SPCPGM) released and caused enrichment of the plasmid for local transfection with the application of the in vitro magnetic field, and this effect was further elucidated. In addition, the functional mechanism was investigated to evaluate the effect of SPCPGM in promoting the vascularization and osteogenesis of artificial bone under the oscillating magnetic field and static magnetic field; this application is expected to provide a new type of angiogenesis strategy and method for bone tissue engineering research.
Evaluation of graphene-derived bone scaffold exposure to the calvarial bone_in-vitro and in-vivo studies
Published in Nanotoxicology, 2022
Yung-Chang Lu, Ting-Kuo Chang, Shu-Ting Yeh, Tzu-Chiao Lin, Hung-Shih Lin, Chun-Hung Chen, Chun-Hsiung Huang, Chang-Hung Huang
Bone defects caused by trauma, resection of bone tumor, osteoporosis, or other pathological problems, are a substantial challenge in orthopedic surgery (Campana et al. 2014; Yan et al. 2019). Autogenous bone graft is still considered as the gold standard for bone substitution. However, the drawbacks of autografts are poor availability, donor-site morbidity, and its resulting complications (Zhang et al. 2019; Shang et al. 2021). Artificial bone substitution developed by tissue engineering is an alternative for bone grafting. The application of biocompatible cell scaffolds has been evaluated for bone tissue engineering in recent years (Shahin-Shamsabadi et al. 2018; Siddiqui et al. 2018). Additive manufacturing or three-dimensional (3D) printing is a cutting-edge technology in BTE. Especially in orthopedic implants, cell scaffolds fabricated via additive manufactured technology (3D bio-printing) have been widely studied (Bandyopadhyay et al. 2020; Chen et al. 2020). With advanced computer-aided design software and different newly developed materials, a 3D bio-printing technique allows researchers to make customized structures with different geometries, sizes, and porosities to obtain more osteo-inductive cell scaffolds (Jariwala et al. 2015). Meanwhile, 3D bio-printing processes are able to control the micro-architecture and composition at the micron-scale of the scaffolds (Zhang et al. 2019). Three dimensional printed Zn-doped mesoporous silica-incorporated poly-L-lactic acid and calcium phosphate cement by incorporating 3D plotted poly(lactic-co-glycolic acid) network have also used to modify osteogenic activity of polymer scaffolds (Qian et al. 2019, 2021).