SBC2007-176715 OPTO-ELECTRIC BIOSENSOR TO EXAMINE IN VITRO TOXICITY STIMULI TO ENDOTHELIAL CELL MOTILITY AND MORPHOLOGY

ABSTRACT An integrated opto-electric biosensor is developed that uses an optically transparent and electrically conductive indium tin oxide (ITO) thin film coated on a slide glass substrate. This biosensor can simultaneously acquire the micro-impedance response and microscopic images of live cells in vitro under various toxic agent stimuli. The dynamic response of live porcine pulmonary artery endothelial cells (PPAECs) exposed to various doses of cytochalasin D are comprehensively examined by monitoring the micro-impedance characteristics at a specified frequency and DICM images using the opto-electric biosensor. The change in PPAEC morphology and motility caused by cytochalasin D clearly illustrates the dosedependent actin filament disruption where optical images are correlated with the changes in the micro-electric impedance. INTRODUCTION Micro-impedance sensing has a great deal of potential in quantifying cell physiology by monitoring cells cultured on small gold electrodes [1] Micro-impedance measurements however, are a sensitive and complex function of both cell-cell and cell-substrate interactions. Cellsubstrate interactions, for example, are mediated by integrin receptors that are functionally linked to the actin cytoskeleton. Biophysical cellsubstrate measurements have, therefore, been correlated with widely accepted biochemically established assays for cytotoxicity [2]. Although micro-impedance measurements have proven to be a valuable tool in examining the response of a large group of cells to various dose of cytochalasin D [3], this technique alone cannot completely evaluate inter cellular interactions. In order to properly examine cell-cell, and cell-substrate adhesion, visual techniques are required. Differential interference contrast microscopy (DICM) provides an excellent method for examining these interactions. Both electrically conductive and optically transparent ITO bioelectrodes [4] are combined with an integrated dynamic live cell imaging system. This system can therefore acquire optical and electrical measurements simultaneously, allowing the observation of cytochalasin D effects on live endothelial cells. Of specific interest is the morphological changes caused by the disruption of actin filaments in the cytoskeleton. This biosensor is able to electrically and optically monitor the real-time and label free drug effect on PPEACs with high temporal and spatial resolutions. The actual effect of three actin-affecting drugs (Cytochalasin D, Latrunculin A, and Jasplakinolide) on cell motility has been quantitatively investigated using video-microscopy of cancer cells [5]. The complicated phenomena of cell-substrate interactions and/or cellcell interaction also represent attractive indicators for studying cell signaling and tumor cell inhibition. In tumor cells, for example, it is a major challenge to inhibit the spreading from primary tumor sites to particular organs, which most likely create metastases killing approximately 90% of cancer patients. The present paper presents a new study of morphology and motility of PPAECs caused by cytochalasin D, which inhibits actin polymerization, by using opto-electric biosensors allowing simultaneous dynamic optical and electrical measurements. EXPERIMENT A. Microscopy DICM Senso

T3-B: Creation of a Small-scale Zero Energy Building

The work presented in this paper details the creation of a small scale model, designed and built by a senior capstone design group, which simulates several attributes of a Zero+ Energy Building (ZEB). This model included a small solar array used to charge a Lithium Ion (LI) Battery, a set of strip heaters designed to hold a set point above the ambient temperature, and removable insulation to demonstrate the increase in consumed power when poor insulation is present. Instrumentation was also added to the small scale model that was capable of monitoring both power consumption by the building and power generation from the solar panels. Finally, a controller was implemented that was capable of wirelessly transmitting the data to a website set up by the students. The completion of this work has provided an excellent demonstration model that can be set up in both middle and high school classrooms

Work in progress - Weaving threads of sustainability into the fabric of the mechanical engineering curriculum

This paper discusses progress in producing problem-based learning curricular materials on sustainability that are incorporated into three mechanical engineering science courses: mechanics of materials, thermodynamics, and dynamic systems and controls. Student learning outcomes for the project are: (1) knowledge of sustainability principles; (2) skill at solving design problems with realistic constraints; (3) attitudes about mechanical engineering as a profession and the importance of sustainability considerations. To assess design skills, we evaluate design project reports using a four-item rubric, and analyze the design objectives and constraints from these reports. To assess attitude, we administer a 28-item attitude survey to senior level students

Opto-Electric Cellular Biosensor Using Optically Transparent Indium Tin Oxide (ITO) Electrodes

Indium tin oxide (ITO) biosensors are used to perform simultaneous optical and electrical measurements in order to examine the dynamic cellular attachment, spreading, and proliferation of endothelial cells (ECs) as well as cytotoxic effects when exposed to cytochalasin D. A detailed description of the fabrication of these sensors is provided and their superior optical characteristics are qualitatively shown using four different microscopic images. Differential interference contrast microscopy (DICM) images were acquired simultaneously with micro-impedance measurements as a function of frequency and time. A digital image processing algorithm quantified the cell-covered electrode area as a function of time. In addition, cytotoxicity effects, produced by the toxic agent cytochalasin D, were examined using micro-impedance measurements, confocal microscopy images of stained actin-filaments, and interference reflection contrast microscopy (IRCM) capable of examining the bottom morphology of a cell. The results of this study show (1) the dynamic optical and electrical cellular characteristics using optically thin ITO biosensors; (2) qualitative agreement between cell-covered electrode area and electrical impedance during cellular attachment; (3) in vitro cytotoxicity detection of ECs due to 3 mM cytochalasin D. The present opto-electric biosensor system is unique in that a simultaneous and integrated cellular analysis is possible for a variety of living cells