title: Noninvasive measurement of effective diffusivities in cell immobilization gels through use of near-infrared spectroscopy.
abstract: Encapsulated cell systems provide some advantages over typical suspension cell cultivations as higher cell densities may be obtained; however, the supply of nutrients to the cells often is a limiting factor in productivity. In this study, we describe the development of a new approach to characterize the effective diffusivity of nutrients in immobilized cell materials. Near-infrared spectroscopy is employed to measure nutrient concentrations within a specially designed diffusion chamber that permits noninvasive sampling at ten spatial positions and multiple timepoints. To demonstrate this technique, we measured the effective diffusivity of glutamine in a cell-free 3% (w/w) agarose gel and determined the effective diffusivity (D(eff)) = 6.46 x 10(-10) m(2)/s, which is in good agreement with theoretical values.
authors.affiliation: Department of Agricultural and Biosystems Engineering, University of Arizona, Shantz Building, Room 403, Tucson, Arizona 85721, USA.
authors.forename: B L
authors.initials: BL
authors.lastname: Frazier
authors.forename: P
authors.initials: P
authors.lastname: Larmour
authors.forename: M R
authors.initials: MR
authors.lastname: Riley
mesh_terms: D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D018914:Cells, Immobilized / Q000166:cytology / Q000378:metabolism*; D004058:Diffusion; D015194:Diffusion Chambers, Culture; D005782:Gels; D005973:Glutamine / Q000378:metabolism; D012685:Sepharose; D013055:Spectrophotometry, Infrared / Q000379:methods
chemical_list: D005782:Gels; D005973:Glutamine; D012685:Sepharose