Diffusion characteristics of microfabricated silicon nanopore membranes as immunoisolation membranes for use in cellular therapeutics
| Autor: | Randy Kirk, Anthony A. Boiarski, Teri West, Francis J. Martin, Michael Cohen, Catherine Smith, Marsha Bratzel, Arfaan Rampersaud |
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| Rok vydání: | 2005 |
| Předmět: |
Silicon
Lysis Endocrinology Diabetes and Metabolism chemistry.chemical_element Immunoglobulin G chemistry.chemical_compound Endocrinology Insulin Secretion Medicine Animals Humans Insulin Fluorescein biology business.industry Dextrans Membranes Artificial medicine.disease Small molecule Hemolysis Rats Molecular Weight Medical Laboratory Technology Nanopore Membrane Glucose chemistry Immunology Biophysics biology.protein business Fluorescein-5-isothiocyanate |
| Zdroj: | Diabetes technologytherapeutics. 7(1) |
| ISSN: | 1520-9156 |
| Popis: | Immunoisolating membranes protect transplanted xenogeneic tissue by physically isolating them from the host. However, most are commercial filter membranes that do not possess all the features needed for immunoisolation. Silicon nanopore membranes are thin layers of silicon containing tens of thousands of nanometer-sized channels, which allow passive diffusion of small molecules. They are excellent size-selective barriers, and the objective of this study was to further characterize their immunoprotective properties and make comparisons with commercial filter membranes.Diffusion across membranes was studied using molecules of different sizes, including fluorescein isothiocyanate-dextrans (relative molecular sizes of 4.4 kDa, 20 kDa, and 70 kDa), glucose (0.18 kDa), insulin (6.1 kDa), and immunoglobulin G (IgG) (150 kDa). Protection from complement-mediated lysis was analyzed by a hemolysis assay. Comparative studies were done with filter membranes that have been reported as immunoisolation barriers. To evaluate if silicon nanopore membranes changed insulin response patterns for glucose-stimulated islets, macrocapsules were constructed with nanopore membranes and filled with pancreatic islets, and dynamic perifusion studies were performed.Relative to commercial membranes, silicon nanopore membranes showed high rates of diffusion for glucose and insulin, and acted as efficient barriers to complement proteins and IgG. No other commercial membrane showed comparable diffusion and immunoisolating properties. Islets placed within the macrocapsule exhibited glucose-responsive insulin secretion in perifusion studies.Silicon nanopore membranes possess unique and desirable diffusion properties as immunoisolation membranes and allow rapid response times for the stimulation of islets by glucose. These features are attributed to the physical properties of the membranes, namely, the straight channels, adequate porosity, and the 5 microm thickness. |
| Databáze: | OpenAIRE |
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