[Hplusroadmap] Fwd: [biomed] eurekalert: 30nm voltmeters, 15MV/m fields inside cells

[Bryan Bishop]

This looks like some interesting research. I do not have a paper on hand 
at the moment to detail the synthesis of this nano-dye. Synopsis: dyes 
that turn colors when subjected to electric fields within the cell. At 
the moment we have to use microscopes to observe the cells, but what if 
we have a wireless nanoscopic photomultiplier of sorts? 

- Bryan

----------  Forwarded Message  ----------

Subject: [biomed] eurekalert: 30nm voltmeters, 15MV/m fields inside 
cells
Date: Saturday 01 December 2007
From: Alejandro Dubrovsky <alito at organicrobot.com>
To: biomedtt <biomed at postbiota.org>

(
http://www.eurekalert.org/pub_releases/2007-11/uom-nvm113007.php
)

Contact: Nancy Ross-Flanigan
rossflan at umich.edu
734-647-1853
University of Michigan
Nano-sized voltmeter measures electric fields deep within cells

ANN ARBOR, Mich.---A wireless, nano-scale voltmeter developed at the
University of Michigan is overturning conventional wisdom about the
physical environment inside cells. It may someday help researchers
tackle such tricky medical issues as why cancer cells grow out of
control and how damaged nerves might be mended.

U-M professor Raoul Kopelman will discuss the device Saturday during a
special session, "Creating Next Generation Nano Tools for Cell Biology,"
at the annual meeting of the American Society for Cell Biology in
Washington, D.C.

"The basic idea behind this field of research is to follow cellular
processes---both normal and abnormal---by monitoring physical properties
inside the cell. There's a long history of research on the chemistry
happening inside the cell, but now we're getting interested in measuring
the physical properties, because physical and chemical processes are
related," said Kopelman, who is the Richard Smalley Distinguished
University Professor of Chemistry, Physics and Applied Physics.

With a diameter of about 30 nanometers, the spherical device is
1,000-fold smaller than existing voltmeters, Kopelman said. It is a
photonic instrument, meaning that it uses light to do its work, rather
than the electrons that electronic devices employ.

Kopelman's former postdoctoral fellow Katherine Tyner, now at the U.S.
Food and Drug Administration, used the nano-voltmeter to measure
electric fields deep inside a cell---a feat that until now was
impossible. Scientists have measured electric fields in the membranes
that surround cells, but not in the interior, Kopelman said.

With the new approach, the researchers don't simply insert a single
voltmeter; they're able to deploy thousands of voltmeters at once,
spread throughout the cell. Each unit is a single nano-particle that
contains voltage-sensitive dyes. When stimulated with blue light, the
dyes emit red and green light, and the ratio of red to green corresponds
to the strength of the electric field in the area of interest.

Tyner's measurements revealed surprisingly high electric fields in
cytosol---the jellylike material that makes up most of a cell's
interior.

"The standard paradigm has been that there are zero electric fields in
cytosol," Kopelman said, "but all of the 13 regions we measured had high
electric field strength---as high as 15 million volts per meter." In
comparison, the electrical field strength inside a typical home is five
to 10 volts per meter; directly under a power transmission line, it's
10,000 volts per meter. Kopelman, Tyner and coauthor Martin Philbert,
professor of environmental health sciences and associate dean for
research at the U-M School of Public Health, published a report on the
nano-voltmeter and their paradigm-shattering findings in Biophysical
Journal in August.

Those findings leave the researchers wondering why electrical fields
exist inside cells.

"I don't know the answer to that," Kopelman said. "I suspect that
finding out exactly what's going on will keep a lot of people working
for a long time." But the ability to measure internal cellular
electrical fields should aid in that endeavor.

It's already known that changes in electrical fields associated with
membranes can play a role in diseases such as Alzheimer's, and
researchers have been exploring the use of externally-applied electric
fields to stimulate wound healing and nerve growth and regeneration.

As for the U-M researchers, Philbert, a neurotoxicologist, is exploring
how intracellular fields change with exposure to nerve toxins, and
Kopelman, who is collaborating with Philbert and researchers in the U-M
medical school on new approaches to cancer detection and treatment, is
interested in comparing electric fields in cancerous and non-cancerous
cells. But they're also open to other avenues of research, Kopelman
said.

"One reason for going to the ASCB meeting is to confer with colleagues
and strategize about where to go next."

###

The researchers received funding from the Defense Advanced Research
Project Agency BioMagnetics program, the National Institutes of Health
and the National Science Foundation - Division of Materials Research.

For more information on Kopelman, visit:
http://www.ns.umich.edu/htdocs/public/experts/ExpDisplay.php?ExpID=437

More on Philbert:
http://www.ns.umich.edu/htdocs/public/experts/ExpDisplay.php?ExpID=1098

American Society for Cell Biology: http://www.ascb.org/

Biophysical Journal: http://www.biophysj.org/


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