BIOGRAPHY

Bioengineering Seminar
Timothy Shafer, Ph.D.
Integrated Systems Toxicology Division
U.S. Environmental Protection Agency
Using Neural Networks on Microelectrode Arrays
To Screen Chemicals for Neurotoxicity and
Developmental Neurotoxicity
For the past 50 years, characterization of chemical hazard in
the United States has been done primarily through the use of
in vivo toxicity testing in mammals. Because of the high cost
and low throughput of in vivo approaches, as many as 80,000
or more chemicals have been released into the environment
without fully characterizing their toxicity hazard. This is
especially true for neurotoxicity and developmental
neurotoxicity. In 2007, the National Academies of Science
issued a report on Toxicity Testing in the 21st Century, which
called for the use of predictive, high-throughput, in vivo
approaches to hazard characterization. This presents a
challenge for neurotoxicity and developmental neurotoxicity
testing, as there are a large variety of targets through which
chemicals may disrupt nervous system function. Many highthroughput in vitro assays for nervous system function focus
on a single target and thus are not useful for screening
chemicals with unknown toxicities. Microelectrode arrays
allow function in interconnected neural networks to be
measured, and can detect changes caused by a variety of
pharmacological, chemical and physical perturbations.
Recently, multi-well MEA plates have been developed, which
has facilitated screening chemicals for potential effects on
neural function. We have used neural networks grown on
MEAs to screen over 100 different chemicals and
nanoparticles, and have demonstrated that they are both
accurate and reproducible in detecting compounds that alter
neural function. Currently, we are developing an assay to
detect the ability of compounds to alter neural network
function during development, and preliminary results indicate
that they can also be used for this purpose.
Thursday, April 30th , 2015
1:30PM – 2:30PM
ENGR, room 3507
Nguyen Engineering Building
BIOGRAPHY
Dr. Shafer received his B.S. from Hope
College in 1986 and Ph.D. in Pharmacology
and Toxicology from Michigan State
University in 1991. He was a postdoctoral
fellow in the Neurotoxicology Division of the
U. S. EPA from 1991 -1994 and in 1995
became a Principal Investigator. Currently,
he is a Principal Investigator in the Systems
Biology Branch of the Integrated Systems
Toxicology Division of the U.S. EPA. Dr.
Shafer has also served as the Acting
Assistant Laboratory Director for Human
Health Research at the EPA, was on the
ALTOX3/NAL study section at NIH and on
the Society of Toxicology Program Committee. He currently is an Associate Editor
for the journal NeuroToxicology and on the
Editorial Board of Toxicology and Applied
Pharmacology. Dr. Shafer has examined the
actions of heavy metals, PCBs, herbicides
and pesticides on ion channel function and
cellular neurophysiology. Currently, his
research is focused on using microelectrode
arrays to develop medium throughput
screens for neurotoxicity and developmental neurotoxicity.
For any questions please
contact Claudia Borke at
cborke@gmu.edu,
(703) 993-4190