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Additive Manufacturing for the Development of Biological Implants, Scaffolds, and Prosthetics
Published in Atul Babbar, Ankit Sharma, Vivek Jain, Dheeraj Gupta, Additive Manufacturing Processes in Biomedical Engineering, 2023
Atul Babbar, Vivek Jain, Dheeraj Gupta, Ankit Sharma, Chander Prakash, Vidyapati Kumar, Kapil Kumar Goyal
Implants are artificial equipment designed to be implanted into the body to supplant or maintain a biological structure and supply medications and supervise physiological processes. Sensory equipment [73]; cerebral and neurological equipment, such as neuronal, cochlear, and retinal implants [74–75]; subcutaneous implants [76]; and cardiological systems, such as vascular bypass, stents, mechanical heart gates, and pacemakers [74], are all illustration of biomedical implants. Sutures and wound dressings [77], vertebral and dentistry implants [78], aesthetic [79], and structural implants [80], such as rods, braces, craniofacial, and hip and knee replacements, are all examples of biomedical implants. Biomedical implants are also utilized as ophthalmic equipment, such as spectacles, contact lenses, and insulin delivery [77].
Bacterial Nanocellulose Biomaterials with Controlled Architecture for Tissue Engineering Scaffolds and Customizable Implants
Published in Miguel Gama, Paul Gatenholm, Dieter Klemm, Bacterial NanoCellulose, 2016
Paul Gatenholm, Joel Berry, Andrea Rojas, Michael B. Sano, Rafael V. Davalos, Kara Johnson, Laurie O’Rourke
Several research groups have developed prototypes of BNC tubes in the required diameter range and with a length of 5–25 cm or more for vascular bypass surgery. The material properties of these vessels depend strongly on the cultivation conditions. The wall of the tubes is formed into the typical transparent BNC hydrogel and is also characterized by a stable inner lumen, good stability of sutures, essential mechanical strength, and the important feature of being permeable to water, other liquids, ions, and small molecules. Moreover, the tubes show very good surgical handling and can be sterilized in standard ways (Klemm et al. 2001). In animal experiments with rats, pigs, and sheep (implantation in the carotid artery) good biocompatibility and performance for at least 13 months were demonstrated (Malm et al. 2012). Histological examination of rats after 1 week, 1 month, and 1 year showed that the tubular BNC implants were integrated by endothelization of the inner surface, colonized on the outer wall by connective tissue, and characterized by the in-growth of vital collagen-forming fibroblasts (Klemm et al. 2001, 2006; Wippermann et al. 2009). Confocal laser scanning microscopy showed that the inner surface of the BNC tubes was smooth and not structured from its preparation (Brackmann et al. 2010). The low surface roughness appears to support good endothelization and to be at low risk of thrombosis or aneurysm (Schumann et al. 2009). Commonly used artificial vascular grafts formed from synthetic polymers such as polytetra-fluoroethylene (PTFE) or polyesters are prone to thrombosis when used as small-diameter vessels, which are essential for coronary artery bypass grafts. A study in which BNC tubes were compared with synthetic grafts over a period of 2 weeks also demonstrated good biocompatibility of BNC and its incorporation in the body. Evaluation of stents (endoluminal vascular prostheses) covered with BNC in a rabbit iliac artery model demonstrated that the implantation was safe and no acute or late vessel occlusion due to stent thrombosis occurred (Bueno et al. 2009).
Cyclopeptide-β-cyclodextrin/γ-glycerol methoxytrimethoxysilane film for potential vascular tissue engineering scaffolds
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Heyi Mao, Yidan Zhang, Lei Wang, Anduo Zhou, Shanfeng Zhang, Jing Cao, Huang Xia
Cardiovascular diseases account for the highest fatality rate worldwide [1] and are estimated to reach 23.3 million deaths by 2030 [2,3]. Common clinical treatments for cardiovascular diseases include decellularized stent implantation, drug therapy, and vascular bypass transplantation [4]. Drug treatment and decellularized stent implantation cannot fundamentally solve the problem and are prone to immune rejection [5,6]. Although vascular bypass transplantation is currently an effective treatment, the lack of autologous vessels has led to the use of vascular allografts and synthetic grafts, including polyethylene terephthalate and expanded polytetrafluoroethylene grafts for the treatment of cardiovascular diseases. These grafts can replace large-diameter blood vessels [7,8]. However, artificial blood vessels prepared from synthetic materials generally have shortcomings such as low biocompatibility and poor endothelial cell adhesion on the surface of the material. They manifest as small-diameter artificial vascular grafts as very easy activation of coagulation reactions to form thrombosis after the surface of a vessel comes into contact with blood, resulting in unsatisfactory long-term patency [9], because of the high incidence of thrombosis, stenosis, and infection, the currently available vascular prostheses cannot effectively solve the problem of small-diameter (<6 mm) vascular transplants [10]. Tissue engineering provides new avenues for solving the problems of small-diameter blood vessels.
Characterization of a heparinized decellularized scaffold and its effects on mechanical and structural properties
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Ji Li, Zhiwen Cai, Jin Cheng, Cong Wang, Zhiping Fang, Yonghao Xiao, Zeng-Guo Feng, Yongquan Gu
Given the limitations of current vascular bypass conduits, a tissue-engineered vascular graft (TEVG) presents an attractive potential solution for the future of vascular surgery [16]. Although a number of tissue engineering approaches using natural and synthetic polymers have shown some promising results [17, 18], numerous hurdles remain. Technical challenges include modulating the mechanical, chemical, and biological properties and clinical challenges include the occurrence of neo-intimal hyperplasia and aneurysmal dilation [19]. Generating TEVGs by decellularization of native blood vessels is a promising approach that is being extensively researched in the field of vascular engineering [20–22]. The ideal decellularization may be defined as the complete removal of the cellular materials from a tissue without adversely affecting the composition, mechanical integrity, and biological activity of the native extracellular matrix (ECM). The host cellular antigens are removed as a result of the decellularization processes, thus reducing the risk of potential inflammatory response and minimizing immune-mediated tissue rejection. In addition, the complex ECM structure is preserved so that adhesion, migration, proliferation and differentiation of recipient cells may be supported [23, 24]. These advantages may hold the potential to overcome some of the current challenges.