(244b) Dielectrophoretic Quantification of Mixed Blood Populations for Detection of Autologous Blood Transfusions

The desire to increase performance in professional athletes has driven some to turn to artificial methods to achieve this end. Autologous blood transfusions – the collection and subsequent reinfusion of a person’s own blood – currently lack a direct test for detection, and has for that reason become a popular “banned method” in performance enhancement. The Athlete’s Biological Passport is meant to monitor an athlete’s long-term trends in numerous biomarkers, and use abnormal variations in the markers to potentially identify blood-doping. It does provide an indirect means of identifying autologous blood doping, but there still lacks a direct detection method.

Using a combination of membrane protein cross-linking and a microfluidic device designed for isolated dielectrophoretic spectroscopy, we demonstrate the ability to detect the presence of 5% reinfused red blood cells (RBCs) in fresh blood.

Red blood cells aging in storage undergo biochemical changes that normal RBCs in circulation do not. This includes changes in cell membrane composition and cell morphology. When stored ex vivo, RBCs begin to lose the number of membrane-bound proteins. This physiological change offers less surface proteins available for cross-linking, resulting in a different dielectrophoretic spectra for stored cells compared to that of fresh RBCs. We use differences in these spectra to discern storage-related changes to blood cell morphology and composition, as a means to directly detect autologous blood doping in athletes.

Further, we show that accurate DEP quantification of these RBC subpopulations requires analysis chambers with confined micron-scale heights. This is because both gravity and the non-uniformity in the electric field gradient produce DEP separation ratios that do not reflect the actual cell mixture percentages. To alleviate this challenge, we present a novel confined DEP design that increases the separation and quantification accuracy of the blood sample for detection of autologous blood doping in endurance athletes.