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Cellulose
Published in Antonio Paesano, Handbook of Sustainable Polymers for Additive Manufacturing, 2022
Cellulose is involved in a recent and growing application area for AM that is bone tissue engineering. After injury, bone heals itself by self-regeneration if the fractures are smaller than a certain (critical) size. Bone fractures at or above critical size are treated with metal and ceramic implants or bone grafting that is a surgical procedure consisting in replacing missing bone with bone harvested from the same patient, donors, cadavers, and species other than human. However, grafting is limited by donor site morbidity (any complication at the site as it heals), donor bone supply shortage, infection, corrosion, stress shielding, and secondary surgery. For large bone fractures and voids, scaffolds are an alternative to grafting, and serve as a 3D template to guide, stimulate, and support the growth of bone tissue on its surfaces. Candidate materials for bone scaffolds must satisfy several requirements, detailed in Section 1.15, such as biocompatibility, biodegradability and bioresorbability (Vert et al. 1992), load-bearing mechanical properties, porosity, be sterile and bioactive, and controlled delivery of bioactive molecules or drugs (Hutmacher 2000; Brown et al. 2009; Porter et al. 2009; Ghassemi et al. 2018). AM is well suited to fabricate bone scaffolds, because it produces geometries customized to the size of specific bone defects and controls scaffold’s mesh resolution, surface finish, and mechanical performance.
Biomaterials in Bone and Muscle Regeneration
Published in Rajesh K. Kesharwani, Raj K. Keservani, Anil K. Sharma, Tissue Engineering, 2022
Shesan John Owonubi, Eric Gayom, Blessing A. Aderibigbe, Neerish Revaprasadu
Bones are dynamic, greatly vascularized living tissues constituting of nerves and blood vessels, constantly being remodeled through the lifetime of individuals. They possess important roles for locomotion, ensuring the human skeleton possesses necessary load-bearing capacity, for the protection of delicate internal organs, and also in the regulation of particular electrolytes in blood (Stevens, 2008). Another vital role of bones is that they provide a suitable environment for the production of blood cells (the marrow) constituting minerals, vitamins and proteins, growing and repairing themselves by their own blood vessels. Bones, unlike other tissues, possess an efficient self-healing capacity, thus in the event of injury or bone fracture, in cases without complications, by necessary reduction and fixation of bone fractures, the formation of new bone can be appreciated after a few weeks. Total/ complete bone union and total recovery may be obtainable only within a month. Conversely, in severe cases with complications, pathological cases, spinal fusion, joint replacement, bone tumor extraction, or some form of birth defect, the normal regenerative capacity of the bone is absent and thus, the patient will require some form of surgery (Kanczler and Oreffo, 2008; Stevens, 2008). At younger ages, the capacity for bones to regenerate is quite high, but this gradually reduces as individuals’ age.
Medical Microwave Imaging and Analysis
Published in de Azevedo-Marques Paulo Mazzoncini, Mencattini Arianna, Salmeri Marcello, Rangayyan Rangaraj M., Medical Image Analysis and Informatics: Computer-Aided Diagnosis and Therapy, 2018
Rohit Chandra, Ilangko Balasingham, Huiyuan Zhou, Ram M. Narayanan
During a bone fracture, soft tissues may also get injured. The commonly used method to detect a bone fracture is using x-rays. However, x-rays cannot detect the injured soft tissues [1]. Microwave imaging can be used to detect the soft tissue injury as well. In [68], a feasibility study using a Newton and the MR-CSI method for functional imaging of the extremity soft tissues of a pig’s hind leg is presented. Salvador et al. [16] presented lesions of clinically relevant sizes and shapes in the menisci, ligaments, and tendons in the knee joint. Images were reconstructed with and without the model of the meniscal tear in the knee. A tear as thin as 1.3 mm × 8 mm was detected in the difference image (but not in the reconstructed image), and two tears separated by a minimum distance of 9 mm were detected.
Bone fracture healing within a continuum bone remodelling framework
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Ina Schmidt, Jacob Albert, Marina Ritthaler, Areti Papastavrou, Paul Steinmann
Despite great progress in medicine and science, it is still a largely open question to understand and predict the adaptation and regeneration processes in human bone. Especially in view of a steadily ageing population, this topic becomes even more important, as the density of bone decreases with age and the risk of fracture thus increases significantly. Bone fractures may not only cause pain and limited mobility but also long-term consequences and financial challenges (Hak et al. 2014; Singaram and Naidoo 2019). It is desirable for the individualised treatment of bone fracture to be optimally adapted to the patient in order to achieve a successful and rapid healing without complications and consequential damage. More and more modern technologies aim to digitise and process individual health data. Although there have been major advances in the computational modelling of bone fracture healing in recent decades, they are rarely used in everyday medical practice (Carlier et al. 2015).
Vitamin D-conjugated gold nanoparticles as functional carriers to enhancing osteogenic differentiation
Published in Science and Technology of Advanced Materials, 2019
Haram Nah, Donghyun Lee, Min Heo, Jae Seo Lee, Sang Jin Lee, Dong Nyoung Heo, Jeongmin Seong, Ho-Nam Lim, Yeon-Hee Lee, Ho-Jin Moon, Yu-Shik Hwang, Il Keun Kwon
Besides traumas, the most common contributing factors to bone fractures originate from structural exacerbation of bones and their low bone mineral density. Vitamin D is a well-known essential nutrient to the human body that is obtainable from supplements, diet, and sun exposure [5]. Synthesis of vitamin D occurs after exposure to sunlight through the liver or the kidney or it is obtained from the diet. The active vitamin D metabolite, 1α, 25-dihydroxyvitamin D3 (1,25(OH)2D3), assumes a vital function in skeletal homeostasis by regulating intestinal absorption of calcium and phosphate [6,7]. In addition, the active form of vitamin D plays a role in inhibition of osteoclastogenesis [8]. On the other hand, deficiency of vitamin D contributes to rickets in children and osteomalacia in adults [9]. Song et al. [10] investigated the osteogenic differentiation of human recombinant bone morphogenetic protein-2 (BMP-2) and vitamin D on adipose stem cells. Piek et al. [11] reported that vitamin D strongly improves the expression of genes on human mesenchymal stem cells as an enhancer of BMP-2-induced osteogenesis. However, adequate intake of vitamin D is not easy for modern people who are customarily indoors. Therefore, many researchers have attempted delivery of vitamin D through nanoparticles [12].