AVS 50th International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI-TuM

Paper BI-TuM11
Drug Testing and Environmental Toxin Detection using Cell-based Biosensors

Tuesday, November 4, 2003, 11:40 am, Room 307

Session: Cell/Surface Interactions
Presenter: A. Natarajan, Clemson University
Authors: A. Natarajan, Clemson University
P. Molnar, Clemson University
K. Sieverdes, Clemson University
A. Jamshidi, Clemson University
J.J. Hickman, Clemson University
Correspondent: Click to Email
In the last decade the threat of environmental pollution, biological warfare and new diseases has increased research into cell-based biosensors. The need for more advanced methods to evaluate candidates has pushed this area of research even further. Cells are natural sensors in the body and react to different bioactive compounds in specific ways. Our research exploits this feature, using the ion channels of electrically active cells like cardiac myocytes, to create a database of specific responses. These responses can then be used to detect the acute presence of a substance. A traditional method of studying drug and toxin effects has been low throughput patchclamp electrophysiology. Our cell-based biosensor consists of a uniform monolayer of cardiac myocytes on a microelectrode array (MEA) with 60 substrate-integrated electrodes. The microelectrode arrays are surface modified and the media used for the cells is defined. Surface analysis was used to verify surface modifications. Long-term recordings of beating cells produced extracellular field potentials in the range 100 µV to 1200 µV, with a beating frequency of 0.5 to 4 Hz. The toxins tested were classified as drugs (epinephrine), heavy metals (Cadmium) and pyrethroids, a group of synthetic pesticides. Pyrethroids modify sodium channels thus disrupting nerve cells in insects. Epinephrine is a well-known stimulant for the heart. Cadmium chloride causes serious illnesses with the same symptoms as lead poisoning. Concentrations used were mainly 1, 10 and 100 µM. Each of the above substances produced specific responses in the action potential signals, changing amplitude, frequency and shape. 10 µM Epinephrine increased spike frequency from 4 Hz to 6 Hz. Our goal is to replace patchclamp electrophysiology with microelectrode arrays as a means to testing many drugs and toxins. Future work involves making this system more stable, creating a larger database and extending the use for chronic detection of compounds.