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A Strategy for Regeneration of Three-Dimensional (3D) Microtissues in Microcapsules: Aerosol Atomization Technique
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Chin Fhong Soon, Wai Yean Leong, Kian Sek Tee, Mohd Khairul Ahmad, Nafarizal Nayan
A microcapsule is a hollow particle with solid shell with a diameter ranging from a few to thousands of micrometers (Gasperini et al. 2014, Sun 1997). Hydrogel based microcapsules are semipermeable that could enable the passage of proteins, nutrients, drugs, and allow the diffusion of oxygen, nutrients, therapeutic products and wastes, while blocking the entry of antibodies and immunocytes (Paredes Juarez et al. 2014). In tissue transplantation, microcapsule functions as an immune-protection. The islet cells placed inside the tiny capsules created a physical barrier to protect the islets from the immune system as reported previously (Vaithilingam and Tuch 2011). Therefore, cell encapsulation in biocompatible and semipermeable biopolymeric membranes is an effective method to overcome rejection of the implanted organ (Rabanel et al. 2009).
Restoration: Nanotechnology in Tissue Replacement and Prosthetics
Published in Harry F. Tibbals, Medical Nanotechnology and Nanomedicine, 2017
Cell encapsulation devices have been developed as research vehicles for studying the release of growth factors, neurotransmitters, and other signaling molecules from cells [143]. Various types of nanotechnology-assisted bioencapsulations have been developed for uses in medicine, biotechnology, tissue regeneration, stem cell therapy, nanorobotics, and artificial cells [144]. Here, we see the convergence of drug delivery, tissue scaffolding, and MEMS microdevices. The boundaries between these types of medical nanotechnol-ogy have become somewhat arbitrary.
Marine Biopolymers
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Islet cells is the kind of cell in the pancreas, including alpha cells and beta cells, the last one producing the insulin, a hormone for controlling the glucose in blood. In the type I diabetic patient, a kind of autoimmune disease, the immune system does not recognize the islet cells and kills them as foreign substances, which makes the body not produce insulin. With this disease, the patients must inject insulin every day, which is inconvenient. Therefore, islet cell transplantation is a promising therapy. However, this therapy needs the pancreas from at least two deceased donors. In this situation, the development of tissue engineering is very necessary (Matsumoto, 2010). In islet cell transplantation, the hydrogels are made from crosslinks of alginate and cation Ca2+ or Ba2+ by the extrusion or electrostatic spraying technique. The last one has the advantage of making the small size gel beads but requiring not a high viscosity of alginate solution. The alginate gel used in many studies of islet cell transplantation showed good compatibility, avoided the attack of lymphocytes, controlled the glucose in plasma just one day after transplantation, and increased the survivor time (Mallett & Korbutt, 2008). Beside finding the source of beta cells with high bioactive like the nature islet cell, the technique in cell encapsulation is developed, from microencapsulation to micro-capsule then nanoencapsulation with only one islet cell for one nanoencapsule. With the 3D bioprinting, the cell scaffolds can get the desired forms. The islet cell nanoencapsule revealed many advantage as enhance the exchange mass by high area/volume ratio, protect islet from the immune system better, can distribute the nanoencapsules to the target organ (Abadpour et al., 2021).
Tissue engineering approaches and generation of insulin-producing cells to treat type 1 diabetes
Published in Journal of Drug Targeting, 2023
Mozafar Khazaei, Fatemeh Khazaei, Elham Niromand, Elham Ghanbari
IPCs, produced from diverse stem cell sources, can be engrafted in vivo. Encapsulating these cells before the implant are promising strategy for treating T1D that avoids the usage of systemic immunosuppression. To protect the graft against allogenic reactions and/or autoantibodies, immune-isolation is required [119]. Cell encapsulation inside a biocompatible semipermeable membrane is commonly used to create this state. These encapsulation devices must also meet certain requirements. The permeability of such a membrane must permit unrestricted nutrients, small molecular and oxygen exchange, as well as excellent insulin kinetics in response to blood glucose variations. Furthermore, they should prevent the passage of high molecular weight complexes such as immune cells and cytokines [66].
An overview of current advancements in pancreatic islet transplantation into the omentum
Published in Islets, 2021
Kimia Damyar, Vesta Farahmand, David Whaley, Michael Alexander, Jonathan R. T. Lakey
In 1980, Lim and Sun23 first reported that single implantation of encapsulated islets into insulin-dependent diabetic rats restored glycemic control for almost three weeks post-transplant. Additionally, the encapsulated islet recipients had significantly lower blood glucose levels compared to rats that received non-encapsulated islets.23 Since then, advancements have been made to improve islet encapsulation procedures for insulin delivery and expand its clinical application. Encapsulation involves the coating of islets in a biocompatible semi-permeable hydrogel membrane, which can then be transplanted into diabetic patients.24 The semi-permeable membrane allows the passage of oxygen, glucose, insulin, and nutrients while preventing the attachment of the immune cells and antibodies to the graft, which can delay rejection.25 Overall, there are two approaches to cell encapsulation for immune isolation of islets. Microencapsulation involves the containment of individual or small groups of islets within a chemically stable microsphere. In contrast, macroencapsulation is the coating of a large mass of islets within a biocompatible planar or cylindrical scaffold.26,27 Currently, the transplantation of microencapsulated islets into the omentum has been investigated.
Cell-laden alginate hydrogels for the treatment of diabetes
Published in Expert Opinion on Drug Delivery, 2020
Lukin Izeia, Tatiane Eufrasio-da-Silva, Alireza Dolatshahi-Pirouz, Serge Ostrovidov, Giovanna Paolone, Nicholas A. Peppas, Paul De Vos, Dwaine Emerich, Gorka Orive
The science of cell encapsulation for diabetes has progressed from basic research to a point of clinically evaluating therapeutically meaningful products on a potentially wide-scale basis. Current progress in device development has created biocompatible, long-term functioning, and retrievable cellular devices for replenishable insulin-producing cell sources. Oxygen and other essential nutrient supplying technologies have been developed that can contribute to long-term function of an efficacious glucose regulating concept. Also, current developments in stem-cell technologies have raised optimism about the scalable generation of insulin-producing cell sources; although some issues still remain. These include production scale up, perfecting the interface between biomaterials, immunology, and cell function, and widening the availability of the few current stem-cell sources. Last but not least, this technology allows retrieval of implanted cell-loaded devices which represents a critical safety aspect and a unique advantage of encapsulation devices. This may especially relevant when living medicines are implanted into accessible sites such as the omental pouch. Progress on some of the key parameters described herein may help to accelerate the translation of insulin releasing cell-laden hydrogels into medical reality.