Capsule alginate polysaccharides

We chose the acidic polymer as the interior member of the capsule forming pair due to the expected compatibility with cells of acidic polysaccharides such as alginate and carboxymethyl cellulose. For this reason, droplet viscosity and, therefore, stability was improved by synthesizing the acidic polymers as higher molecular weight analogues of the corresponding polybases. 

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... 

Figure 21.6. PPARgamma gene silenced (SiRNA) fetal derived mesenchymal cells embedded within polysaccharide capsules and implanted subcutaneously for 28 days. Capsule are sectioned and stained for presence of oil droplets using Oil red-O, AP3 antibodies and alcian blue and Sirius red. Rows 2, 5, and 6 are thin sections of capsules in which embedded adipogenic progenitor cells have been silenced for expression of a transcription factor that regulates cellular differentiation and development typically found within adipose tissues, (lx 10 /mL alginate).

Peptide conjugated alginate to enhance cell-to-matrix and tissue responses inside polysaccharide capsules... 

Figure 21.12. Mineralized polysaccharide (alginate-chitosan) nanocapsules A) TEM of nanocapsules with alginate stained black/dark grey surrounded by a lighter grey chitosan outer shell B) XRD analysis of a representative nanocapsule shows that calcium and phosphate ions are concentrated on capsules and therefore indicates the formation of a calcium phosphate outer shell. This provides evidence that alginate-chitosan capsules have been formed.

Figure 5.50. Examples of drag delivery using hydrogel membranes. Top carbon dioxide gas pressure causes rapture of membrane, controlled by the membrane thickness and amount of CO2 being produced. Bottom drug release from a polysaccharide alginate capsule, facilitated by multivalent/monovalent ion-exchange, controlled by the molecular weight of the alginate and sire of the capsule. Reproduced with permission from Adv. Drug Deliv. Rev. 2002,54, 53.

In this report, using capsules containing a-chymotryp-sin (Chy) and alginate (Alg) prepared by an interfacial condensation, effects of adding Alg and its gelation on the reactivities of Chy were studied. Alg is a major structural polysaccharide and is gelled by the addition of divalent metal ions without changing the temperature [5-7]. 

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