Research Experience

07/05-Present Dr. Irene C Solomon

• Developmental Plasticity of RespiratoryNeural Control in Neonatal Rats
  My previous research experience in Dr. Solomon’s laboratory has raised my interest in the study of neural plasticity and I would like to implement new engineering methods to better investigate the mechanisms responsible for long-term and short-term physiological adaptations.The overall goal of my proposed research is to study the developmental plasticity of the dynamics underlying the respiratory neural control system in neonatal rats in vivo. The specific aims include: 1) identifying ranges of frequency oscillations, their relative power, and the timing of spectral activity within the bursts in developing neonates, 2) to examine the time course for the proposed shift of peak(s) in the frequency spectrum to higher frequencies, as an index of maturation of the respiratory system, and 3) to quantify the changes in the fast oscillatory behavior including interburst variability and the degree of synchronization underlying inspiratory motor discharge.

• Micropatterning of Cardiac Cells for Structural and Functional Study (Pictures)
  The ability to design and control cellular interactions on a micrometer scale is essential for tissuegenesis and tissue engineering. My goal was to design an inexpensive and simple approach to engineer patterns of excitable heart cells. Two specific aspects were involved in this study: to determine the optimized conditions for micropatterning of proteins and cells, and to quantify the effects of protein patterning on cardiac cell arrangement and cell function. PDMS moldings were utilized for deposition of attachment factors by microcontact printing onto desired surfaces, along with the usage of blocking agents to optimize pattern specificity. Cell morphology was studied by labeling and imaging the cytoskeletal protein arrangement using phalloidin stain. Optical mapping of calcium waves revealed highly anisotropic conduction with slower electrical propagation across lines of excitable CM as compared to normal cell culture with random cell distribution. This in vitro system was presented for its usage as a model for heart disease, as well as its helpfulness to guide the way to design biological circuits analogues for solving computational problems at a local meeting. This work was supported by funding from the Whitaker Foundation (RG-02-0654) and by a training grant from the NIH for the Interdisciplinary Biomedical Research Program.

• Non-invasive Continuous Measurement of Oxygen Concentration in Engineered Cardiac Tissue (Pictures)
  Biocompatible optical oxygen sensors were embedded in polydimethysiloxane (PDMS) scaffolds and excited by a light-emitting diode. Emitted phase angle differences caused by oxygen consumption from cells cultured on top of the scaffolds were then measured and analyzed. My teammate and I distributed specific tasks in data collection and analysis for each culture, while working closely in troubleshooting and improving measurement techniques. Cell viability was examined using nuclear dye and results from cultures show that contractile cardiac myocytes (CM) have about three times higher oxygen uptake rate as compared to not metabolically active fibroblast. This project was part of my summer research where I was supported by a peer-review training grant funded by the National Institutes of General Medical Sciences (R25-GM62492).

• 3D Topographic Guidance of Engineered Heart Tissue (Pictures)
  My task was to analyze fluorescent images of the cell cytoskeleton taken from 3D engineered tissue constructs in order to validate hypothesized predictions of the cellular tensegrity model. Analyzed data from each participating lab member were compared and discussed in lab meetings. Our data suggested that geodesic domes found in the cytoskeleton are dynamic structures that can be architected by microenvironments, thus giving us the ability to induce structural changes of cellular constructs and enhancing tissue functions.

Other Projects

08/2004-05/2005 Senior Design Project - Third Prize of URECA Senior Design Competition

• Design of a Versatile LED based Illumination Module (Pictures)
  The goal for this design project is to develop a versatile light emitting diode (LED) based illumination module for dynamic fluorescence imaging. The primary objective is to design a stable circuit with steady current to each high-powered LED. Each LED provides a defined wavelength (with a high signal to noise ratio) and fast “on time” (ability to rapidly switch between on and off). This system is versatile and inexpensive and suitable for macroscopic fluorescence imaging systems. Another objective is to design an illumination system that is capable of switching between at least two different wavelengths, at high speeds so as to facilitate dynamic, real time, ratio metric measurements.

Selected Abstracts:

1. Yu H, Chen X, Solomon IC. Developmental changes in respiratory network complexity and burst timing during gasping in urethane-anesthetized rat in vivo. Experimental Biology, Washington, DC, April 2007.
2. Reid IM, Yu H, Lin R, Solomon IC. Long-term facilitation differentially affects inspiratory network complexity in urethane-anesthetized P12-13 versus P14-15 neonatal rats. Experimental Biology, Washington, DC, April 2007
3. Yu H, Chen X, Solomon IC. Developmental changes in inspiratory network complexity and burst timing in vivo. 33rd Annual Northeast Bioengineering Conference, Stony Brook, New York, March 2007.
4. Yu H, Chen X, Solomon IC. Developmental changes in respiratory network complexity and burst timing in urethane-anesthetized rat in vivo. Neuroscience 2006, Atlanta, GA, October 2006.
5. Yu H, Chen X, Foglyano R, Wilson CG and Solomon IC. Respiratory network complexity in neonatal rat in vivo and in vitro. The Xth Oxford Conference, Lake louise, Alberta, Canada, September 2006.
6. Yu H, Ali A, Ameerally A, Strey H and Entcheva E. Design of a versatile, LED based illumination module used for macroscopic fluorescence imaging. SUNY Stony Brook URECA celebration, Stony Brook, NY, April 2005.
7. Kostov Y, Rao G, Bien H, Farrell M, Yu H and Entcheva E. Minituarized fluorescence lifetime system for oxygen measurements in cardiac cell constructs. Annual BMES Meeting, Philadelphia, PA, October 2004.
8. Yu H, Malik S and Entcheva E. Micropatterning of heart cells by microcontact printing of attachment proteins. SUNY Stony Brook URECA celebration, Stony Brook, NY, April 2004.
9. Bien H, Farrell M, Yu H, Kostov Y and Entcheva E. Lifetime fluorescence measurements of oxygen uptake in cardiac cell networks using oxygen-sensitive scaffolds. Annual BMES Meeting, Nashville, TN, October 2003.
10. Bien H, Dasari V, Farrell M, Yu H, Yin L, Chun C-Y and Entcheva E. Mechanical and spatial determinants of cytoskeletal geodesic dome formation in cardiac fibroblasts. ASM Conference on Bio-, Micro- and Nanosystems, New York, NY, July 2003.

Last Updated: December 2005
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