Investigating Interactions of Trehalose-Containing Liposomes with Human Red Blood Cells

A major obstacle in using intracellular sugars for the cryopreservation of mammalian cells is the inability of cells to synthesize or actively accumulate these sugars. We are investigating the use of liposomes, which are synthetic, microscopic vesicles, for the intracellular delivery of stabilizing sugars into mammalian cells. This study examines the interactions of trehalose-containing liposomes with human red blood cells (RBCs). Unilamellar liposomes were synthesized using an extrusion method to contain trehalose in the aqueous core. Liposomal preparations were labeled with a lipophilic fluorophore rhodamine B chloride (R18) at quenching concentrations (4 mol%), or the 5(6)-carboxyfluorescein [5(6)-CF] marker to label the intraliposomal aqueous phase. Flow cytometry and fluorescent microscopy were used to assess the interactions between fluorescently labeled liposomes and RBCs. The delivery of liposomal contents into RBCs was assessed by spectrophotometric measurement of intracellular trehalose. The res...