title: Investigations on gel forming media for use in low gravity bioseparations research.
abstract: Microgravity research includes investigations designed to gain insight on methods of separating living cells.  During a typical separation certain real-time measurements can be made by optical methods, but some materials must also be subjected to subsequent analyses, sometimes including cultivation of the separated cells.  In the absence of on-orbit analytical or fraction collecting procedures, some means is required to "capture" cells after separation.  The use of solutions that form gels was therefore investigated as a means of maintaining cells and/or macromolecules in the separated state after two types of simple ground-based experiments.  Microgravity electrophoresis experiments were simulated by separating model cell types (rat, chicken, human and rabbit erythrocytes) in a vertical density gradient containing low-conductivity buffer, 1.7%-6.5% Ficoll, 6.8-5.0% sucrose, and 1% SeaPrep low-melting temperature agarose and demonstrating that, upon cooling, a gel formed in the column, and cells could be captured in the positions to which they had migrated.  Two-phase extraction experiments were simulated by choosing two-polymer solutions in which phase separation occurs in normal saline at temperatures compatible with cell viability and in which one or both phases form a gel upon cooling.  Suitable polymers included commercial agaroses (1-2%), maltodextrin (5-7%) and gelatin (5-20%).
authors.affiliation: National Bureau of Standards, Boulder, CO 80303.
authors.forename: P
authors.initials: P
authors.lastname: Todd
authors.forename: D C
authors.initials: DC
authors.lastname: Szlag
authors.forename: L D
authors.initials: LD
authors.lastname: Plank
authors.forename: S G
authors.initials: SG
authors.lastname: Delcourt
authors.forename: M E
authors.initials: ME
authors.lastname: Kunze
authors.forename: F H
authors.initials: FH
authors.lastname: Kirkpatrick
authors.forename: R G
authors.initials: RG
authors.lastname: Pike
mesh_terms: D000818:Animals; D002469:Cell Separation / Q000379:methods*; D002645:Chickens; D003470:Culture Media; D004586:Electrophoresis / Q000379:methods; D004912:Erythrocytes / Q000166:cytology*; D005780:Gelatin; D005782:Gels; D006801:Humans; D011134:Polysaccharides; D011817:Rabbits; D051381:Rats; D012685:Sepharose; D018474:Weightlessness Simulation
chemical_list: D003470:Culture Media; D005782:Gels; D011134:Polysaccharides; C008315:maltodextrin; D005780:Gelatin; D012685:Sepharose