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Proceedings Paper

Point-of-care, portable microfluidic blood analyzer system
Author(s): Teimour Maleki; Todd Fricke; J. T. Quesenberry; Paul W. Todd; James F. Leary
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Paper Abstract

Recent advances in MEMS technology have provided an opportunity to develop microfluidic devices with enormous potential for portable, point-of-care, low-cost medical diagnostic tools. Hand-held flow cytometers will soon be used in disease diagnosis and monitoring. Despite much interest in miniaturizing commercially available cytometers, they remain costly, bulky, and require expert operation. In this article, we report progress on the development of a battery-powered handheld blood analyzer that will quickly and automatically process a drop of whole human blood by real-time, on-chip magnetic separation of white blood cells (WBCs), fluorescence analysis of labeled WBC subsets, and counting a reproducible fraction of the red blood cells (RBCs) by light scattering. The whole blood (WB) analyzer is composed of a micro-mixer, a special branching/separation system, an optical detection system, and electronic readout circuitry. A droplet of un-processed blood is mixed with the reagents, i.e. magnetic beads and fluorescent stain in the micro-mixer. Valve-less sorting is achieved by magnetic deflection of magnetic microparticle-labeled WBC. LED excitation in combination with an avalanche photodiode (APD) detection system is used for counting fluorescent WBC subsets using several colors of immune-Qdots, while counting a reproducible fraction of red blood cells (RBC) is performed using a laser light scatting measurement with a photodiode. Optimized branching/channel width is achieved using Comsol Multi-Physics™ simulation. To accommodate full portability, all required power supplies (40v, ±10V, and +3V) are provided via step-up voltage converters from one battery. A simple onboard lock-in amplifier is used to increase the sensitivity/resolution of the pulse counting circuitry.

Paper Details

Date Published: 14 February 2012
PDF: 13 pages
Proc. SPIE 8251, Microfluidics, BioMEMS, and Medical Microsystems X, 82510C (14 February 2012); doi: 10.1117/12.909051
Show Author Affiliations
Teimour Maleki, Purdue Univ. (United States)
Todd Fricke, Techshot, Inc. (United States)
J. T. Quesenberry, Techshot, Inc. (United States)
Paul W. Todd, Techshot, Inc. (United States)
James F. Leary, Purdue Univ. (United States)

Published in SPIE Proceedings Vol. 8251:
Microfluidics, BioMEMS, and Medical Microsystems X
Holger Becker; Bonnie L. Gray, Editor(s)

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