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Polymer Materials for Oral and Craniofacial Tissue Engineering
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Iriczalli Cruz Maya, Vincenzo Guarino
Lastly, alginate is a natural polysaccharide extracted from brown sea algae, composed of D-manuronic acid and L-guloronic acid. Alginate is a biocompatible, non-toxic, biodegradable and low-cost material (Kolambkar et al. 2011; Westhrin et al. 2015). Alginate-based materials have been used in the form of hydrogels, microspheres, microcapsules and fibers for tissue engineering and drug delivery systems. Alginate hydrogels or scaffolds can be prepared in the presence of cations such as Ca2+ at low concentrations via the ionic interaction between the cation and the carboxyl functional group of alginate (Guarino et al. 2015; Barron and He 2017). To improve the biological and mechanical properties of alginate materials, it has been used in combination with other synthetic or natural polymers and growth factors (Bonino et al. 2011; Lan et al. 2018). For encapsulation of cells, alginate is also a promising material for its ability to form microgels that can serve as a 3D reservoir (Yao et al. 2012).
Burns
Published in Tor Wo Chiu, Stone’s Plastic Surgery Facts, 2018
Donor sites are traditionally dressed with Kaltostat (calcium alginate – there is exchange for tissue sodium and the released calcium activates haemostasis). As alginates dry out and become difficult/painful to remove, some suggest that they should be exchanged for a less adhesive dressing once haemostasis has been achieved.
Reflux Disease
Published in John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford, Head & Neck Surgery Plastic Surgery, 2018
Alginate preparations have traditionally been used in the treatment of GORD symptoms such as heartburn, and there is evidence for the effectiveness in LPR of one alginate preparation that is currently available in the UK and Europe,32 but not in the United States. Alginate is a non-systemic treatment derived from seaweed, and has little in the way of side effects, although some individuals find liquid preparations difficult to tolerate due to the thick consistency. Tablet formulations are available but the tablets are large and need to be sucked or chewed; they have a chalky texture.
Alginate-based matrix tablets for drug delivery
Published in Expert Opinion on Drug Delivery, 2023
Natalia Veronica, Paul Wan Sia Heng, Celine Valeria Liew
Numerous research endeavors have led to the successful development of alginate-based sustained released oral formulations. However, alginate is not without its drawbacks. As a charged polymer, the hydration behavior of alginate can be influenced by the hydration environment (e.g. pH, presence of cations and anions). This is reflected in the gel layer properties. Alginate as a pharmaceutical excipient comes in various grades with different properties, including particle size, molecular weight, viscosity, and chemical compositions, especially the M/G ratio. These inherent properties of alginate can affect the properties of the gel layer formed and the subsequent drug release behavior. Despite its limitations, alginate holds great potential for application in oral sustained release formulations. To this end, further studies should be performed to address key concerns in using alginate in oral sustained release formulations, which include the susceptibility of the gel layer to crack formation and lamination in an acidic environment, poor gel strength and pH-dependent gel layer properties. Incorporating cross-linkers, pH modifiers, and other polymers into the formulations help to ameliorate the limitations relating to gel properties. Modifications of alginate, including but not limited to co-processing, polymer grafting and IPN formation, have been successfully applied to enhance existing features and impart new properties to alginate. However, the toxicity and safety profiles of the modified alginate need to be evaluated. Furthermore, process-related hazards should also be addressed.
Assessing the immunosuppressive activity of alginate-encapsulated mesenchymal stromal cells on splenocytes
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2022
Sandhya Moise, Luigi Dolcetti, Francesco Dazzi, Paul Roach, Lee Buttery, Sheila MacNeil, Nick Medcalf
Various hydrogel materials have been studied for cellular encapsulation such as fibrin [27–30], alginate [20,28,31–33] Pullulan [34] and collagen [35,36]. Alginate is a polysaccharide derived from seaweed and crosslinks in the presence of divalent cations. It is an FDA-approved material and, when ultrapure, is highly biocompatible and has a low immunogenic response [37] making it a promising biomaterial for cellular delivery. Alginate microspheres have been explored for loading and delivering immunomodulatory biomolecules [13,38,39] for various in vivo applications [33]. In addition, alginate encapsulation of MSCs has been shown to prolong MSC survival and retention in vivo [26,40] and more recently to enhance the therapeutic immunomodulatory effect of MSCs in treating osteoarthritis [41].
Engineered biomaterial strategies for controlling growth factors in tissue engineering
Published in Drug Delivery, 2020
Na Guan, Zhihai Liu, Yonghui Zhao, Qiu Li, Yitao Wang
Alginate is a natural polysaccharide extracted from brown algae and is composed of various proportions of β-d-mannuronic acid (M) and α-l-guluronic acid (G) residues (Gu et al., 2004). Common alginate usually originates from algae and has a high degree of physicochemical heterogeneity, which can affect its quality and induce different applications (Mhanna et al., 2017). Alginate has many excellent properties, such as biocompatibility, low toxicity, low cost and has been widely studied in the field of biomedicine. Alginate gel induced by bivalent cation can be used for wound healing, therapeutic drugs, protein delivery and cell transplantation (Li et al., 2018). The main advantage of alginate is that stimulate the extracellular matrix and create a moist environment so that reduces the risk of bacterial infection in wounds and accelerates wound healing. What’s more, alginate hydrogel has also been used in cell transplantation in tissue engineering (Reakasame & Boccaccini, 2018). It transports cells to specific sites and provides an artificial matrix for new blood vessels. Alginate gels can also be administrated orally or injected into the body and can also be used in pharmaceutical fields (Kalaf et al., 2016; Yan et al., 2016).