Molecular Diagnostics Using A Single Drop of Biological Fluid

AUTHORS: Ana Egatz-Gomez, Antonio A. Garcia

ADDRESS: Harrington Department of Bioengineering, Arizona State University, Tempe, Arizona  

BIOGRAPHIES: Dr. Antonio A. García is the Associate Director of the Hispanic Research Center and Professor of Bioengineering in the Ira A. Fulton School of Engineering at Arizona State University where he has focused on designing and characterizing surfaces and colloids for diagnostic devices. His work has been published in a wide variety of chemistry, engineering, and biology journals including J. of Physical Chemistry, I&EC Research, The Analyst, and J. of Microbiological Methods. He was Associate Editor of the Journal of Research in Science Teaching 2003-2005. His educational efforts in collaboration with faculty in the Colleges of Liberal Arts and Engineering were featured on the cover of Journal of Chemical Education (September 2000 issue). Recently, his work with colleagues in engineering and sciences on combining surface chemistry and fractal texturing in order to move water drops using magnetic fields was featured in Science Daily and Earth and Sky Radio (August 2006).

Ana Egatz-Gomez is a PhD candidate at the Department of Bioengineering at Arizona State University, USA, working under the direction of Dr. Antonio Garcia. She graduated as an Electronics Engineer from National Technologic University at Mendoza, Argentina in 1994, and received a MS degree in Industrial Economics and Science and Technology Management from University Carlos III, Madrid, Spain, in 2002. She has also worked as a consultant, maintenance engineer, and instructor in Argentina, Spain and USA.

ABSTRACT: Our group has created a new strategy to change the paradigm of sample pretreatment and analysis in order to meet the demands of personalized medicine based on recent developments in nanotechnology. We have developed a new microfluidic method that relies on magnetic fields to control the movement of drops on superhydrophobic surfaces using magnetizable micro or nano-scale particles that are introduced into the liquid. Key elements of operations such as movement, coalescence, and splitting of aqueous and biological fluid drops, as well as electrochemical measurement of dopamine and glucose have been demonstrated. Electrochemical measurements are performed using a sequence of 'Sample', 'Blank', 'Wash' and 'Reagent' solutions that are moved into and out of a three-electrode assembly in order to perform square-wave voltammetry or chronoamperometry. The creation of pH gradients that can be maintained during drop splitting also holds promise as a method for removing albumin from serum samples for blood analyses. Digital magnetofluidics is a technology with great potential as a means for rapid preparation and analysis of microliter-sized drop samples, thus reducing animal blood usage. For example, with this technology, it would be possible to only use one drop of blood from the tail of a mouse instead of sacrificing the mouse due to the small amount of sample needed to perform a wide variety of molecular analyses. During our talk, we will provide a number of digital videos that demonstrate how this system works.


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