(394b) ABO Membrane Antigens Alter Dielectric Properties of Red Blood Cells

Human blood is of incredible diagnostic interest because it is easily obtainable and can provide a plethora of information about a person’s general health such as protein, iron, vitamin and electrolyte levels.  The goal of this research is to expand blood diagnostic capabilities by using dielectrophoresis as a means to provide an ABO-Rh blood type classification from blood.  Prior results from our lab suggest that the dielectric properties (permittivity and conductivity) of human erythrocytes change dependent upon ABO-Rh antigen expression.   The Clausius-Mossotti factor is directly dependent upon the dielectric properties and thus alternating current dielectrophoresis is a mechanism by which ABO-Rh blood types can be identified by quantifying red blood cell behaviors.  Additional prior results with β(1-3) galactosidase treatment demonstrated cleavage of the ABO antigens without harming the erythrocyte and verification of the galactose residues in the supernatant.  Treatment yields immunologically bare erythrocytes whose membrane surface is bereft of the ABO antigens. Previous experiments done in a 0.9S/m conductivity buffer have shown that the range over which the crossover frequency occurs for ABO-Rh blood types in their native state is 17MHz, whereas the range over which the crossover occurs for the modified samples is 5MHz.  This uniformity in cross over frequency is an indication that the ABO antigens influence crossover frequency of the red blood cells.  Further experiments at lower medium conductivities of 0.01S/m and 0.1S/m have been conducted over a large frequency range  In addition to measuring the crossover frequencies of blood samples, the dielectrophoretic spectra as a function of frequency have been constructed using a novel intensity profile approach.  This approach allowed typical dielectrophoretic traces to be plotted versus frequency for each ABO-Rh blood type, both native and modified samples.  In this manner, not only could the crossover frequencies of the blood types be compared, but also the curvature of their traces, giving a more accurate method of distinguishing between blood types.