Purification of Polymers Used for Fabrication of an Immunoisolation Barrier<sup>a</sup>

Prokop, A.; Wang, Taylor G.

doi:10.1111/j.1749-6632.1997.tb52197.x

Cited by 34 publications

(30 citation statements)

References 13 publications

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“…39 In our study, all of the purification procedures were found to significantly decrease the polyphenol content in the alginate. Even the simplest purification procedure, that is, that based on the protocol by Prokop and Wang, 25 which involved only one chloroform and two charcoal treatments, was efficient enough to significantly reduce the polyphenol content. This implies that only a minimum degree of chemical treatment is required to remove most of this contaminant from alginate.…”

Section: Discussionmentioning

confidence: 99%

“…11,12,30 In addition, others have observed that alginate purification induced a change in solution viscosity. 25,31 In the present study, we showed that the final purity level and viscosity of the alginates varied depending on the applied purification protocol. Nevertheless, all of the evaluated methods reduced the levels of the three contaminants and increased the viscosity of the alginate solution.…”

Section: Introductionmentioning

confidence: 92%

“…Results are presented as average value Ϯ standard error of the mean. Steps of the three published in-house purification methods 23,25,26 evaluated in the present report ( a supplementary steps added to the original protocol).…”

Section: Statistical Analysesmentioning

confidence: 99%

“…The Protanal LF 10/60 alginate was separated into four batches: the first batch was not purified (Prot-raw), and the others were purified according to three different in-house purification procedures that were originally published by Prokop and Wang 25 (Prot pur P), de Vos et al 23 (Prot pur D), and Klöck et al 26 (Prot pur K). Briefly, in the purification procedure by de Vos et al, 23 alginate was dissolved, under constant stirring, in 1M sodium ethyleneglycotetraacetic acid (EGTA) solution at 4°C into a 1% solution and filtered over a 0.22 m filter.…”

Section: Alginate Purificationmentioning

confidence: 99%

“…The present article reports the results of a comparative study of five alginate preparations: a pharmaceutical-grade alginate in its nonpurified state, the same alginate after purification according to three published in-house methods, 23,25,26 and a commercially available "ultrapure" alginate. The relative efficiencies of the purification methods were evaluated using two criteria, the contamination levels of the purified alginates and their solution viscosities.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of alginate purification methods: Effect on polyphenol, endotoxin, and protein contamination

Dusseault

Tam

Ménard

et al. 2005

J Biomedical Materials Res

137

106

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Alginate, a polysaccharide extracted from brown seaweed, is widely used for the microencapsulation of islets of Langerhans, allowing their transplantation without immunosuppression. This natural polymer is known to be largely contaminated. The implantation of islets encapsulated using unpurified alginate leads to the development of fibrotic cell overgrowth around the microcapsules and normalization of the blood glucose is restricted to a very short period if it is achieved at all. Several research groups have developed their own purification method and obtained relatively good results. No comparative evaluation of the efficiencies of these methods has been published. We conducted an evaluative study of five different alginate preparations: a pharmaceutical-grade alginate in its raw state, the same alginate after purification according to three different published methods, and a commercially available purified alginate. The results showed that all purification methods reduced the amounts of known contaminants, that is, polyphenols, endotoxins, and proteins, although with varying efficiencies. Increased viscosity of alginate solutions was observed after purification of the alginates. Despite a general efficiency in decreasing contamination levels, all of the purified alginates contained relatively high residual amounts of protein contaminants. Because proteins may be immunogenic, these residual proteins may have a role in persisting microcapsule immunogenicity.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 92%

Section: Statistical Analysesmentioning

confidence: 99%

Section: Alginate Purificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation of alginate purification methods: Effect on polyphenol, endotoxin, and protein contamination

Dusseault

Tam

Ménard

et al. 2005

J Biomedical Materials Res

137

106

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Effect of poly‐L‐lysine coating on macrophage activation by alginate‐based microcapsules: Assessment using a new in vitro method

Juste

Lessard

Henley

et al. 2005

J Biomedical Materials Res

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The characteristics of the microcapsule surface, which interacts directly with the host macrophages, may have a role in the biocompatibility of alginate-poly-L-lysine (PLL)-alginate (APA) microcapsule. The objectives of the study were: 1) to develop and validate a simple, rapid, and sensitive in vitro method for assessing microcapsule biocompatibility, based on microcapsule coincubation with macrophages and measurement, by reverse transcriptase-polymerase chain reaction, of cytokine mRNA expression, and 2) to evaluate the effect of alginate purification and PLL coating on macrophage activation. The mRNA expression of tumor necrosis factor-alpha and interleukin-1beta was significantly higher when macrophages were coincubated with beads made with nonpurified compared with purified alginate (p<0.01, p<0.05, respectively) and negative control (p<0.001) or with APA microcapsules compared with non-PLL-coated alginate beads and negative control (p<0.001). The mRNA expression of interleukin-6 differed significantly only when APA microcapsules were compared with a negative control (p<0.05). These results confirm that alginate purification improves microcapsule biocompatibility, and suggest that PLL is not completely covered and/or neutralized by the second alginate incubation and thus has a role in the host macrophage activation. The assay is sensitive to both alginate contaminants and microcapsule surface characteristics and may be a useful tool for the development of biocompatible microcapsules.

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Role of protein contaminants in the immunogenicity of alginates

et al. 2010

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Alginate is widely used for cell microencapsulation and transplantation. There is a lack of standardization of alginate purity and composition. In a previous study, we compared different alginate purification methods and concluded that polyphenol and endotoxin contaminants were eliminated efficiently but residual protein contaminants persisted with all of the methods under evaluation. The objective of this study was to test the hypothesis that residual proteins play a role in the immunogenicity of certain alginate preparations. Using preparative size exclusion chromatography (SEC) and a large scale purification protocol that was derived from the findings obtained with SEC, we substantially decreased the protein content of alginate preparations. When implanted into mouse peritoneum, barium alginate beads made of alginates that were purified using SEC or the derived large scale protocol induced significantly less pericapsular cell adhesion than those made with control alginates. In conclusions, these results suggest that removing residual protein contamination may decrease the immunogenicity of certain alginate preparations. The measurement of proteins could be used as a screening method for evaluating alginate preparations.

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Purification of Polymers Used for Fabrication of an Immunoisolation Barrier^a

Cited by 34 publications

References 13 publications

Evaluation of alginate purification methods: Effect on polyphenol, endotoxin, and protein contamination

Evaluation of alginate purification methods: Effect on polyphenol, endotoxin, and protein contamination

Effect of poly‐L‐lysine coating on macrophage activation by alginate‐based microcapsules: Assessment using a new in vitro method

Role of protein contaminants in the immunogenicity of alginates

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Purification of Polymers Used for Fabrication of an Immunoisolation Barriera

Cited by 34 publications

References 13 publications

Evaluation of alginate purification methods: Effect on polyphenol, endotoxin, and protein contamination

Evaluation of alginate purification methods: Effect on polyphenol, endotoxin, and protein contamination

Effect of poly‐L‐lysine coating on macrophage activation by alginate‐based microcapsules: Assessment using a new in vitro method

Role of protein contaminants in the immunogenicity of alginates

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Product

Resources

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Purification of Polymers Used for Fabrication of an Immunoisolation Barrier^a