Paramagnetic alginate beads with a 10-100 microns size range have been developed. These beads, when activated with chloroacetic anhydride and covalently coupled to avidin (30 micrograms/mg beads), were able to bind biotinylated goat anti-mouse (B-GAM) antibody (Ab). The beads with immobilized antibody were then used as a model system for the capture and non-enzymatic release of CD34+ (KG1a) cells. A maximum of 82% KG1a (average = 65 +/- 16.1%) cell capture, and 57% (average = 51 +/- 5.9%) cell release has been attained using this model system. Optimization of the system in terms of further bead size reduction, and in terms of developing a system to recover released cells with high purity, will make an excellent system for cell capture and nonenzymatic release.

Bifunctional silane reagents (3-iodopropyl)trimethoxysilane (1), (gamma-glycidoxypropyl)trimethoxysilane (2), and [1-(trimethoxysilyl)-2-(m- (or p-)chloromethyl)phenyl]ethane (3) were used to covalently link goat anti-mouse (GAM) antibodies (Ab) to glass microbeads and cuprammonium rayon hollow-fiber dialyzers. An average of 0.79 and 0.83 microgram of GAM Ab/cm2 was immobilized on the hollow-fiber dialyzers and the glass beads, respectively. The antibodies immobilized on glass microbeads or on hollow-fiber dialyzers were then used to selectively deplete CD34+ cells or CD4+ peripheral blood mononuclear cells (PBMC), respectively. Glass microbeads depleted 80% CD34+ cells with good selectivity, and the hollow-fiber dialyzers depleted an average of 81% CD4+ PBMC.

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