Polymer Materials for Oral and Craniofacial Tissue Engineering
Vincenzo Guarino, Marco Antonio Alvarez-Pérez in Current Advances in Oral and Craniofacial Tissue Engineering, 2020
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).
Thalassotherapy and Marine Cosmeceuticals
Leonel Pereira in Therapeutic and Nutritional Uses of Algae, 2018
The main polysaccharide found in the brown seaweeds (Phaeophyceae) is alginate (see Fig. 3.2, Chapter 3), a linear copolymer of mannuronic (M) and guluronic acid (G). The extraction process is based on the conversion of an insoluble mixture of alginic acid salts of the cell wall in a soluble salt (alginate) which is appropriate for the water extraction (Lahaye 2001, Pereira 2013b). This polysaccharide is derived from several genera of brown algae (e.g., mixed Fucales and Laminariales) that are utilized as raw materials by commercial alginate producers (Pereira 2013b). Because of their chelating properties, alginates are widely used as gelling agents in cosmetics and as thickeners, protective colloids, or emulsion stabilizers (Mafinowska 2011). With their water-binding capacity, they moisturize the skin and have a unique immunostimulating activity (Table 12.1) (Fabrowska et al. 2015).
Malignant Wounds
Margaret O’Connor, Sanchia Aranda, Susie Wilkinson in Palliative Care Nursing, 2018
There are several strategies available to help with actively bleeding wounds. For slow oozing, sucralfate paste or an alginate can be applied (Thomas, Vowden & Newton 1998b; Emflorgo 1998). Caution is advised in using alginates. There is evidence that these dressings can actually cause bleeding in fragile tumours (Grocott 1998). In wounds with moderate-to-heavy bleeding, the use of a haemostatic surgical sponge (such as Spongostan or Oxycell) will promote rapid haemostasis. However, these dressing can be expensive and are not usually available in the community. Alternatively, topical adrenaline or tranexamic acid can be applied, but they should be used only under medical supervision. Caution is advised because adrenaline can cause ischaemic necrosis by local vasoconstriction (Grocott 2000). Excessive bleeding that refuses to stop might need referral to a surgeon for cautery or ligation.
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).
Alginate-based matrix tablets for drug delivery
Published in Expert Opinion on Drug Delivery, 2023
Natalia Veronica, Paul Wan Sia Heng, Celine Valeria Liew
Alginate is widely used in the food industry as stabilizers and thickeners, functioning as one of the most important food additives [5]. As a biodegradable, biocompatible and nontoxic biopolymer, alginate has also found applications in the biomedical (e.g. tissue engineering, cell culture) [6–10] and pharmaceutical industries (e.g. hydrogels, nanoparticles, tablets) [11–14]. Tablets are by far the most frequently used oral dosage form due to their compactness and ease of administration. Interest in alginate as a pharmaceutical excipient for tablet formulations lies in its swelling and gelling properties along with its unique pH sensitivity. The success of alginate in sustaining drug release has been widely demonstrated. Although less common, alginate has also been investigated as a nature-derived tablet disintegrant.