JHU biomedical engineering primary faculty
Leslie Tung, PhD
Professor of Biomedical Engineering
Director, Undergraduate Program
Office: Traylor 703
Lab: Cardiac Bioelectric Systems Laboratory
B.S., M.S., Electrical Engineering, Massachusetts Institute of Technology, 1972
Ph.D., Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 1978
Engineering the Heart in a Dish
Our research involves the study of functional properties of engineered networks of living cardiac cells at varying structural levels that include single cells, cell strands, 2D sheets, and 3D tissue. We culture neonatal rat ventricular cells and use microfabrication techniques to direct the growth of the cells into individual cell shapes or into geometrically patterned multicellular networks. To visualize the spatial propagation of excitatory wave fronts in the cells over relatively large distances, we developed a method called "contact fluorescence imaging" that can optically map the electrical activity of cell monolayers stained with a voltage-sensitive dye.
With these tools, we have developed a simple and controlled, cultured cell model suitable for the study of a major form of aberrant propagation called reentry. Reentry underlies many cardiac arrhythmias, including life-threatening ventricular fibrillation and milder forms of tachycardia or flutter in the atria, ventricles, and atrioventricular node. We use theoretical and computational models to complement our experimental work and to assist in the interpretation of the maps of electrical activity.
We are also investigating the electrophysiological responses of our cell networks to electrical stimulation in the context of electrical cardioversion and defibrillation. Other interests in the lab include the synthesis and characterization of 3-D constructs of cardiac tissue and the use of genetic approaches to alter the electrophysiological characteristics of cardiac cells.
Entcheva, E., Lu, S. N., Harrison, R. L., Sharma, V. and Tung, L. Contact fluorescence imaging (CFI) of reentry in monolayers of cultured neonatal rat ventricular cells. J Cardiovasc Electrophysiol 11:665-676, 2000.
Tung, L. and Kleber, A. G. Virtual sources associated with linear and curved strands of cardiac cells. Am J Physiol Heart Circ Physiol 279:H1579-H1590, 2000.
Sharma, V. and Tung, L. A theoretical and experimental study of sawtooth effect in isolated cardiac cell-pairs. J Cardiovasc Electrophysiol12:1164-73, 2001.
Sharma, V. and Tung, L. Effects of uniform electric fields on intracellular calcium transients in single cardiac cells. Am J Physiol Heart Circ Physiol 282(1):H72-H79, 2002.