| 1. |
- Grant, S. C., et al.
(författare)
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Alginate assessment by NMR microscopy
- 2005
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 16:6, s. 511-514
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Tidskriftsartikel (refereegranskat)abstract
- Alginate hydrogels have long been used to encapsulate cells for the purpose of cell transplantation. However, they also have been criticized because they fail to consistently maintain their integrity for extended periods of time. Two issues of critical importance that have yet to be thoroughly addressed concerning the long-term integrity of alginate/poly-L-lysine/alginate microcapsules are: (i) are there temporal changes in the alginate/poly-L-lysine interaction and (ii) are there temporal changes in the alginate gel structure. NMR microscopy is a non-invasive analytical technique that can address these issues. in this report, we present data to demonstrate the utility of H-1 NMR microscopy to (i) visualize the poly-L-lysine layer in an effort to address the first question, and (ii) to observe temporal changes in the alginate matrix that may represent changes in the gel structure.
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| 2. |
- Simpson, N. E., et al.
(författare)
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Biochemical consequences of alginate encapsulation : A NMR study of insulin-secreting cells
- 2006
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 27:12, s. 2577-2586
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Tidskriftsartikel (refereegranskat)abstract
- In this study we explore the biochemical consequences of alginate encapsulation on beta TC3 cells. C-13 NMR spectroscopy and isotopomer analysis were used to investigate the effects of encapsulation on several enzymatic processes associated with the TCA cycle. Our data show statistically significant differences in various enzymatic fluxes related to the TCA cycle and insulin secretion between monolayer and algainate-encapsulated cultures. The principal cause for these effects was the process of trypsinization. Embedding the trypsinized cells in alginate beads did not have a compounded effect on the enzymatic fluxes of entrapped cells. However, an additional small but statistically significant decrease in insulin secretion was measured in encapsulated cells. Finally, differences in either enzymatic fluxes or Qlucose consumption as a function of bead diameter were not observed. However, differences in T-2, assessed by H-1 NMR microimaging, were observed as a function of bead diameter, suggesting that smaller beads became more organized with time in culture, while larger beads displayed a looser organization.
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