Biocompatibility alginate

Alginate is widely used in separation, food, textile, and paper applications. Moreover, due to its biocompatibility, alginate has been extensively used in the biomedical field as a drug delivery material [34, 35], a wound dressing [36], a scaffold [37, 38] and for cell encapsulation [39]. Therefore, the BC-alginate composite has been extensively studied in many fields. Comparative characteristics of BC-alginate composites prepared from various methods are shown in Table 14.1. 

Mock, G. (1998) Biocompatible alginates for use in biohybrid organs, in New Developments in Marine Biotechnology (eds Y. Le Gal and H.O. Halvorson), Plenum Press, New York, London, pp. 61-64. 

Polymer grafting can be used to alter chemical and physical properties of a homopolymer. For example, Sawhney and Hubbell [18] grafted polyethyleneoxide to poly L-lysine to enhance biocompatibility of polylysine and improve the polylysine-alginate capsules. Stevenson and Sefton [19] modified alginate by grafting it with hydroxyalkyl methacrylate, again to improve the biocompatibility and to allow for polymerization by means of y-irradiation. Covalently modified (co)-polymers have not been evaluated in this study. 

Microspheres and nanoparticles often consist of biocompatible polymers and belong either to the soluble or the particle type carriers. Besides the aforementioned HPMA polymeric backbone, carriers have also been prepared using dextrans, ficoll, sepharose or poly-L-lysine as the main carrier body. More recently alginate nanoparticles have been described for the targeting of antisense oligonucleotides [28]. As with other polymeric carrier systems, the backbone can be modified with e.g. sugar molecules or antibody fragments to introduce cellular specificity. 

Biodegradable polymers, both synthetic and natural, have gained more attention as carriers because of their biocompatibility and biodegradability and therewith the low impact on the environment. Examples of biodegradable polymers are synthetic polymers, such as polyesters, poly(orfho-esters), polyanhydrides and polyphosphazenes, and natural polymers, like polysaccharides such as chitosan, hyaluronic acid and alginates. 

For alginates, the copolymer composition (ratio of mannuronic to guluronic acid units) can influence the ultimate complex properties. These include elasticity as well as permeability and mechanical resistance of coacer-vates cast into 2D or spherical membrane structures. The type of polymer-polymer coacervate (precipitate, sol, network) will also often be highly molar mass dependent, with useful membranes formd within a narrow window. This often does not correspond to the molar mass range required for bioapplications, which is dictated by factors such as cell toxicity and biocompatability. 

Several other biodegradable, biocompatible, injectable polymers are being investigated for drug delivery systems. They include polyvinyl alcohol, block copolymer of PLA-PEG, polycyanoacrylate, polyanhydrides, cellulose, alginate, collagen, gelatin, albumin, starches, dextrans, hyaluronic acid and its derivatives, and hydroxyapatite. ... 

In the present study, the polysaccharide alginic acid (AlA) with molecular weight (Mw) of 250 000 was chosen as a polyanion. The strong basic protein protamine sulfate (PtS) with Mw about 5000 was used as a polycation. The calcium carbonate matrices were successively employed as a core material because they dissolve in mild conditions and are non toxic. Our motivation to study this combination was to reach the more biocompatible shell composition. 

Fe-alginates in aqueous solutions are capable of degrading organic compounds at biocompatible pH values [6]. This material consists of encapsulated Fe-cross-linked alginate. Alginic acid is a naturally occurring polysaccharide that will crosslink in the presence of di- and trivalent cations. 

As a result of their biocompatibility and their gelling capacity, alginates have been applied in the engineering of biomaterials [155]. Beside their major... 

The drive towards microencapsulation systems based on the use of synthetic hydrophilic methacrylate based polymers is fueled by their proven biocompatibility, (56) hydrolytic stability, (57) ease of synthesis (66, 67) and enormous structural diversity made possible through copolymerization. In contrast, interest in polysaccharide gel formers such as alginate is founded upon the relative ease of capsule formation under physiological conditions. It would seem inevitable that attempts be made to combine the host biocompatibility and stability of methacrylate based polymers with the ease of capsule formation... 

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