Video - David Lominadze - "Microcirculation, Role of Fibrinogen - 11_11_2009

Abstract: Fibrinogen (Fg) is a well known marker of inflammation. It is also known as an inflammatory agent. The slightest elevation of its content in plasma increases the risk of cardiovascular complications associated with diseases such as hypertension, diabetes, and stroke. In addition, it was found that Fg hinders autoimmune reaction and complicates targeting of cancer cells for treatment. However, little is known regarding the effects of Fg in microcirculation and in various blood circulatory pathologies. This presentation is intended to show the mechanisms of Fg effects on vascular reactivity, regulated production of endothelin-1 (ET-1), endothelial cells (ECs), EC integrity, erythrocyte aggregation, and platelet thrombogenesis. Specifically, I will discuss mechanisms of Fg-activated extracellular signal- regulated kinases-1 and 2 (ERK-1/2) signaling leading to exocytosis of Weibel-Palade bodies, formation of filamentous actin (F-actin) in ECs, and changes in expression of endothelial tight junction proteins. Effects of Fg on activation of metalloproteinases (MMPs), formation of oxygen radical species in ECs, and changes of EC proteome will also be shown. Possible applications of nano-technology in assessment of Fg interaction with ECs, platelets, and erythrocytes, as well as methods to measure blood cell-to-cell interaction forces will be discussed.

Biography:  Dr. David Lominadze has been an Assistant Professor, tenure track, in the Department of Physiology and Biophysics, University of Louisville since 2008. He has a B.S. and MS in Physics/Biophysics from the Tbilisi State University, Tbilisi, Georgia. He completed his Ph.D. at the Institute of Physiology, Georgian Academy of Sciences (Tbilisi, Georgia) where he worked on changes of blood rheological properties in microvessels. He held the position of Head of Microrheology Sector, Microcirculation Research Center at the Institute of Physiology as he came to the Center for Applied Microcirculatory Research, University of Louisville, as an Adjunct Assistant Professor in 1992. Since then he has worked on changes of platelet thrombogenesis and red blood cell aggregability during copper deficiency and hypertension. Dr. Lominadze returned to Louisville in 1999 after he left the USA 8 months earlier. Since then he developed a research program related to changes in platelet thrombogenesis and erythrocyte aggregability during hypertension development, for which he was granted a National Scientist Development Award from the American Heart Association in 2002. Focusing his research on the role of Fg in microcirculation during hypertension, he received funding from the National Heart and Blood Institute in 2006. Dr. Lominadze’s research is focused on mechanisms involved in Fg and EC, platelet, and erythrocyte interactions, effects of Fg on vascular responses, remodeling, and permeability. He is a collaborator on NIH funded projects by Drs. Suresh C. Tyagi (Univ. of Louisville) and Menq-Jer Lee (Wayne State University).

Formats available: MPEG-4 Video (.m4v), MPEG-4 Video (.m4v), Flash Video (.flv)

Tags: kentucky nanonet, engineering platforms for exploring cellular and molecular processes, bioengineering,nanotechnology, university of louisville, department of physiology and biophysics, microcirculation, fibrinogen

Rafael V Davalos - Contactless Dielectrophoresis (cDEP) - 3-10-10

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Abstract: ;Dielectrophoresis (DEP), the motion of a particle due to its polarization in the presence of a non- uniform electric field, can be used to differentiate cell types based upon their intrinsic electrical properties. A number of applications based upon this principle have been effectively demonstrated. Unfortunately, cellular isolation techniques employing conventional DEP generally require direct contact between electrodes and a sample fluid, which can induce fouling, bubble formation and unwanted electrochemical effects. We have invented an alternative method to provide the spatially non-uniform electric field required for DEP in which electrodes are not in direct contact with the biological sample. In this method, an electric field is created in the sample microchannel using electrodes inserted into two other microchannels (filled with conductive solution), which are separated from the sample channel by thin insulating barriers. These insulating barriers exhibit a capacitive behavior and therefore an electric field can be produced in the main channel by applying an AC field across the barriers. The absence of contact between electrodes and the sample fluid inside the channel prevents bubble formation and avoids any contaminating effects that the electrodes may have on the sample. We have designed and fabricated microfluidic devices based on this new technique and have observed DEP responses (DEP trapping and cell chaining) in multiple cancer cells, including human leukemia, breast, and prostate cancer cells. The major advantages of contactless dielectrophoresis are lack of extensive sample preparation (no antibody labeling, one needs only prepare a single cell preparation), the speed of isolation (minutes from the time of sample acquisition), and a simplified inexpensive fabrication process.
Biography:

Dr. Shamus McNamara - A Thermally Driven Pump for Microfluidic Applications - Dec 2, 2009

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Abstract: ;Microfluidic pumps are of great interest today for use in a variety of applications, including lab-on-a-chip, -TAS, gas chromatography, and gas spectroscopy. This talk will discuss a thermally driven gas pump, called a Knudsen Pump that features no moving parts. The pump can be operated to pull vacuum, or to compress a gas. Through pneumatic pressure, the pump can manipulate liquids in a microfluidic channel. The results from a number of pump configurations will be presented, including recent work that demonstrates the most efficient Knudsen pump reported to date.

Biography:  Shamus McNamara received the B.S. and M.S. degrees in Electrical Engineering at Rensselaer Polytechnic Institute in 1994 and 1996, respectively, and the Ph.D. degree in Electrical Engineering at the University of Wisconsin- Madison in 2002. He did his post-doctoral work at the University of Michigan, and is a co-founder of a startup company. He is currently an Assistant Professor at the University of Louisville in the Department of Electrical and Computer Engineering, where he is also the associate director of the Micro-Nano Technology Center. His research interests lie in the fields of microfabrication and MEMS.

High School Macrofluidics Lab 2

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Elizabeth Mansfield, one of the 2010 High School Teacher Fellows, presents part two of her work on how to demonstrate microfluidic concepts to high school students.

High School Macrofluidics Lab 1

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Elizabeth Mansfield, one of the 2010 High School Teacher Fellows, presents part one of her work on how to demonstrate microfluidic concepts to high school students.