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Magnetic Beads (Dynabead™) Toxicity To Endothelial Cells At High Bead Concentration: Implication For Tissue Engineering Of Vascular Prosthesis
Published 2004 · Medicine, Biology
Magnetic beads (Dynabeads™) have been used for the purification of endothelial cells. One application for this procedure may be for single-stage seeding of bypass grafts. The number of endothelial cells (EC) isolated is crucial and therefore to increase the number of cells extracted, a higher number of Dynabeads™ per cell may need to be used. The effect of large numbers of CD31 Dynabeads™ on cell proliferation/metabolism is unknown. We undertook this study using CD31-coated Dynabeads™ and EC from human umbilical vein. EC were coated at concentrations of 4, 10, or 50 beads per cell. The cells were cultured for 6 days with control being normal EC. Cellular proliferation was assessed by trypsinization of cells and metabolism assessed with an Alamar blue™ viability assay. In a further experiment a compliant polyurethane graft was single-stage seeded with both coated Dynabeads™ and normal EC. The results showed that using a higher number of beads per cell resulted in a reduction in cell proliferation and a reduction in cell metabolism. The total number of Dynabeads™-coated cells in culture compared to controls (%) by day 6 were 30.7±2.56, 41.3±9.8 and 59.2±7.3 for 50, 10, and 4 beads per cell, respectively. The corresponding results for Alamar blue were 43.7±1.2, 61.8±1.4, and 72.1±4.3. The seeded grafts showed reduced metabolism with the Dynabeads™-coated EC. In conclusion, high numbers of beads per cell have a late detrimental effect on cell proliferation and metabolism. Therefore for single-stage seeding lower numbers of Dynabeads™ will need to be used with resultant reduction in the number of available EC.