(314a) Blood Typing in a Dielectrophoretic Microdevice

Other than conventional pathological techniques, medical analysis laboratories utilize flow cytometers for many standard blood tests. This relatively expensive equipment ranges from $30,000 to $150,000 [1]. The fee for each test to be done on these cytometers ranges above $50 with medical costs rising annually [2]. Eventually, it could be possible to design an inexpensive portable microdevice that can be used to perform multiple blood tests. The microdevice is expected to cost not more than 25 USD each. These microdevices could also find good application in understanding and identifying sickle cell anemia. The present cost of each sickle cell anemia kit which work using electrophoresis, have ranged about $69- $175 each [3,4]. Specialized microdevices have potential to be user-friendly, cost effective medical diagnosis kits. In the present work, dielectrophoresis is used to study the human blood of types A+, B+, AB+, and O+ and quantify them. Dielectrophoresis, a type of electrokinetics, is the use of a non-uniform AC field to manipulate and characterize cells [5,26. This tool has potential use in medical diagnosis applications, particularly those involving cell analyses.

The present work describes a multifold approach that includes experimentation, analysis, and correlation with existing physiological data. In Experimentation, the dielectrophoretic field is generated within the microdevice using platinum electrodes positioned 250 microns apart in a perpendicular configuration to create a non-uniform AC field [7]. Whole blood samples are diluted using Phosphate Buffer Saline in 1:60 V:V ratio and introduced into the microdevice via sample ports. An AC current of 1 MHz and 5 Vpp (volts peak to peak) is applied. The red blood cells polarize in the electric field and interact with each other to form pearl chains along the electric field lines. The preferential movement of these cells is dependent on blood type, as each blood type has a different surface property. The movement of the erythrocytes is recorded via video microscopy at 10-second intervals for 4 min. In the Analysis, the images are processed to get the X, Y position, cell radius, cell area, bound width and bound height of the cells using Axiovision 4.5 software. Based on the difference in optical intensity of the cells and the background in the image, the software selects the cells or conglomeration of cells. Then, the cells are properly separated and identified to get accurate position coordinates. The images have shown characteristic differences in their movement and this movement up to 120 seconds is studied. In Interpretation, the images are divided into 6 equal sized sextants to analyze the cell position distribution in the field using a MATLAB program. The sextants are made across the mid field line and two vertical trisection lines. Then the number of cells in each sextant at each time interval is normalized with the initial number of cells. Then plots are made for this normalized number of cells in each sextant as a function of time for each blood type separately. In order to check for consistency in data, experiments are performed for 3 different days.

The data showed signature trends for each positive blood type. The characterization of the blood types using this technique would lead to portable medical diagnostic device capable of detecting blood type. This is useful in times of medical emergency for quick blood transfusion.

1.http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1... 2.http://www.thebody.com/gmhc/issues/novdec01/cheaper.htmlhttp://www.fores...? mi=2136 3.https://www2.carolina.com/webapp/wcs/stores/servlet/ProductDisplay?membe... 4.http://www.forestry-suppliers.com/product_pages/View_Catalog_Page.asp?mi... 5.Pohl, H. Dielectrophoresis. New York, NY: Cambridge University Press, 1978. 6.Pethig, Ronald. Dielectrophoresis: Using Inhomogeneous AC Electrical Fields to Separate and Manipulate Cells. Crit. Rev. Biotech. Vol.16 (4), pp. 31-348, 1996 7.Minerick, A., Zhou, R., Takhistov, P., and Chang, H. ?Manipulation and Characterization of Red Blood Cells with Alternating Current Fields in Microdevices.? Electrophoresis. vol. 24, pp. 3703-3717, 2003.