Alginate gels

Dextrans are particularly useful and are employed as a plasma substitute. A concentration of about 6% dextran (50,000-100,000 relative molecular weight) has equivalent viscosity and colloid-osmotic properties to blood plasma. Dextran can also be used as non-irritant absorbent wound dressings, an application also suited to alginate gels. 

At end, it is important to mention that calcium pectate gel beads were compared with calcium alginates gel beads for all entrapment uses [65, 66] in this work, the authors determined the pore size of the beads by size exclusion chromatography using dextran standards and other solutes. 

Since the matrices of AB cements bear some similarity to alginate gels they most probably fall into type 3. 

Alginate gels, formed chemically, do not melt upon heating and are stable up to the boiling point of water. They can be liquefied by chemical reactions that will convert the alginate into a soluble salt. 

Fig. 11.18 SEM photographs of the alginate gel modified with silanol groups and calcium ions after soaking in SBF for 7 days.

Calcium alginate gels, 4 728 Calcium alloys, 4 530 Calcium aluminate, 2 345t Calcium aluminate cement, 2 415-416 5 500t, 502... 

Chitosan, cross-linked chitosan alginate gels (in presence of calcium ions) starch egg white, soybean and whey proteins... 

Rao and Hall compared the activities of algae, cyanobacteria, and photosynthetic bacteria entrapped in an alginate gel and in a hydrophilic polyurethane. Their opinion was that such systems could maintain effectiveness for years using sunlight as an energy source. 

The polyurethane-entrapped algae showed reasonable activity compared to free suspensions of cells. The activity fell sharply after a few days, however. The authors hypothesized that the decrease could have been the result of residual toxicity of the polyurethanes. They also noted that the previous method of entrapping the cells in alginate gels performed better. Our work focused on tlie differences in diffusion tlirough the entrapping polymer. Baillez et al. also discussed mass transport in the foams as a contributing factor. In summary, direct entrapment resulted in an immediate reduction in viability of the cells. 

Entrapment in alginate gel Adsorption on modified cellulose Cross-link with glutaraldehyde Adsorption on bone char... 

Alginates, unique hydrocolloids extracted from selected species of brown seaweed (kelp), interact with calcium ions to produce thermally stable gels. Using this interaction, flavor oils may be encapsulated or entrapped in the algin gel matrix. Encapsulation is accomplished at ambient temperatures. Products may be used "as is" (wet) or subsequently dried. This technique offers the potential for novel flavor effects, flavor protection, and new food products. 

An enzyme which hydrolyzes the cellobiose to glucose, /3-glucosidase is immobilized in a sodium alginate gel sphere (2.5 mm in diameter). Assume that the zero-order reaction occurs at every point within the sphere with k0 = 0.0795 mol/sm3, and cellobiose moves through the sphere by molecular diffusion with Ds = 0.6 x 10 5 cm2 /s (cellobiose in gel). Calculate the effectiveness factor of the immobilized enzyme when the cellobiose concentration in bulk solution is 10 mol/m3. 

Cheetham, P. S. J., K. W. Blunt, and C. Bucke, "Physical Studies on Cell Immobilization Using Calcium Alginate Gels," Biotech. Bioeng. 21 (1979) 2155-2168. 

Hg2+ Urease Entrapment in alginate gel Amperometric - LOD = 64ggr1 - Water and [14]... 

Using the negatively charged nafion film, Rodriguez et al. have improved the sensitivity of urease immobilized reaching a limit of 64 and 55 pgl 1 of mercury and copper, respectively, instead of 2.9 and 29.8 mgl 1 using the alginate gel alone [14],... 

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