Transport characterization of membranes for immunoisolation.
Biomaterials
; 17(3): 257-66, 1996 Feb.
Article
em En
| MEDLINE
| ID: mdl-8745322
ABSTRACT
This study relates to the diffusive transport characterization of hollow fibre membranes used in implantable bio-hybrid organs and other immunoisolatory devices. Techniques were developed to accurately determine the mass transfer coefficients for diffusing species in the 10(2)-10(5) MW range, validated and then used to study one membrane type known to effectively immunoisolate both allografts and xenografts in vivo. Low-molecular-weight diffusing markers included glucose, vitamin B12 and cytochrome C; higher-molecular-weight molecules were bovine serum albumin, immunoglobulin G, apoferritin and a range of fluorescein-tagged dextrans. Overall and fractional mass transfer coefficients through the hollow fibres were determined using a resistance-in-series model for transport. A flowing dialysis-type apparatus was used for the small-molecular-weight diffusants, whereas a static diffusion chamber was used for large-molecular-weight markers. For diffusion measurements of small-molecular-weight solutes, convective artefacts were minimized and the effect of boundary layers on both sides of the membrane were accounted for in the model. In measuring diffusion coefficients of large-molecular-weight species, boundary layer effects were shown to be negligible. Results showed that for small-molecular-weight species (< 13,000 MW) the diffusion coefficient in the membrane was reduced relative to diffusion in water by two to four times. The diffusion rate of large-molecular-weight species was hindered by several thousand-fold over their rate of diffusion in water.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Órgãos Artificiais
/
Materiais Biocompatíveis
/
Membranas Artificiais
/
Modelos Teóricos
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Biomaterials
Ano de publicação:
1996
Tipo de documento:
Article