Human Heart, Eels Generate
Interest as Implant Power Sources
IN BRIEF
The industrywide trend toward miniaturization Flashing forward 10 years into the future,
is presenting device makers with what seems some implantable devices could be powered via
like a paradoxical request: Reduce the size of the same mechanisms used by the electric eel to
implantable devices while increasing functionality. shock its predators and prey.
Adding functionality, however, typically translates While exploring the use of nanotechnology for
into increasing the size of the battery, and thus the biological energy conversion systems, researchers
overall package size, to power these new features. at Yale University (New Haven, CT; www.yale.
Because of this design conundrum, researchers edu) and the National Institute of Standards
have shifted their focus to augmenting or even and Technology (NIST; Gaithersburg, MD; www.
eliminating batteries as implant power sources. nist.gov) sought to understand how eels produce
Instead, researchers are exploring more-natural their electric shock. The researchers found that an
power sources such as the human heart and electric eel’s cells generate electric pulses from several ion
eels to support next-generation implantable devices. channels and pumps that act as natural nanoscale
One such project involves a UK-based conductors. Employing computer models, the
consortium that has designed and clinically tested researchers labored to engineer artificial cells that
an in-body microgenerator able to harvest energy functioned in the same manner.
from a human heartbeat to power such implants as “In the simplest terms, the electrocyte
pacemakers and implanted cardio defibrillators. [electrogenic cell] converts chemical energy from
Lead by Zarlink Semiconductor (Ottawa, ON, food into an ion concentration gradient, which
Canada; www.zarlink.com), the Self-Energizing is a means to store energy,” explains David
Implantable Medical Microsystem (SIMM) project LaVan, a NIST researcher. “The electrocyte then
consists of several UK companies in collaboration releases the ion concentration gradient in pulses
with clinicians at Southampton University that convert the chemical potential energy into
Hospital (Southampton, UK; www.suht.nhs.uk). electricity. We showed that many phenomena, such
“The driver for us was to allow more as the relationship between energy delivered to
functionality to be incorporated into the pacemaker trigger the cell and the resting time before the cell
by making the battery smaller and being able to can fire again are related to the ion channels and
drive more power into the pacemaker to power ion pumps and do not need to be explicitly defined.”
extra functions and therapies,” says Martin Upon successfully creating these models, the
McHugh, business development manager for team discovered that the artifical cells were quite
Zarlink’s Advanced Packaging group and SIMM efficient. The natural electrocytes boast an efficiency
project coordinator. The consortium sought to of roughly 15%, which LaVan believes could be
achieve this goal by harvesting the differential further improved through design modifications.
energy in the chambers of the human heart to Armed with a strong model, the researchers’
drive a linear generator. By augmenting the next step is taking their findings from the computer
battery using the natural in-body energy supply, to the lab. “With a fundamental understanding of
the microgenerator was able to provide one-third how these cells function, it is now conceivable to
of the electricity needed to operate a pacemaker, build a synthetic electrogenic cell to power medical
according to the group.
The design of the microgenerator was strongly
influenced by the team’s desire to incorporate
the part into the existing device assembly. By
not altering the design of the pacemaker, the
consortium hopes to avoid delays in market
launch and to enable a seamless transition
for doctors. “If the surgeon was implanting a
pacemaker and the next day a microgenerator
was implemented, he shouldn’t technically see
any difference in his procedure,” McHugh says.
When attached to a pacing lead, a microgenerator can provide
The group achieved this design goal by integrating
one-third of the electricity needed to operate a pacemaker.
the microgenerator into the pacing lead.
Another driver of the microgenerator’s design
proved to be the requirements for harvesting
energy. Other systems have necessitated that a
person perform some sort of voluntary physical
activity, such as walking, in order to generate
energy, according to McHugh. In contrast, he adds,
the SIMM microgenerator can produce energy
through both voluntary and involuntary actions,
such as sleeping.
Once optimized, incorporation of the
microgenerator could allow for smaller implant
batteries in the packaging, thereby allowing
for more space inside the device for additional
components. Freeing up internal real estate in
the device opens the door for integration of added
functionality in order to enhance patient care.
McHugh cites increased wireless technologies—
Zarlink’s specialty—for home monitoring
capabilities as well as various sensors and
components aiding in therapeutic tasks as potential
candidates to fill the newly available space.
Although the first iteration of the
microgenerator will likely augment smaller
batteries, future versions could replace batteries
entirely. The consortium predicts that the first
models of the microgenerator could be ready for
general use in as little as three years.
implants or to genetically engineer a more-efficient
biological cell for the same uses,” LaVan says. He
states that the team has its eye on applying the
technology to retinal prostheses once actualized.
But in order to actualize the technology, the
team must first determine which design approach
it will take to physically develop the cells: natural
or synthetic. To engineer a synthetic version of the
cells, the researchers envision a silicon or silica
construction enhanced with functional coatings.
However, they predict that a significant design
challenge would arise in engineering a synthetic
analog of the ion pump.
And yet a natural cell design would have its
share of pros and cons as well. LaVan notes
that one drawback would be that using proteins
would incite an immune response. However, the
advantages could be numerous. “The appealing
feature is that you use a natural-occurring energy
source that is in the body—something like glucose
or fatty acids—and convert that into electricity
using a biological system,” explains LaVan. “The
natural constraints on the biological system mean
that it is inherently better suited for operation
inside the body; as examples, there are no
hazardous materials to worry about and no waste
heat to deal with.”—Shana Leonard
IQS (North Olmsted, OH; www.iqs.com),
a provider of enterprise risk and quality
management software, has relocated its
headquarters to accommodate recent growth
and increased training and conference needs....
TomTec Imaging Systems (Unterschleissheim,
Germany; www.tomtec.de), a supplier of
medical imaging software solutions, and
Advanced Medical Imaging Development
(Sulmona, Italy; www.amid.biz) have expanded
their partnership to develop 2-D and 3-D
quantification tools for echo planar and magnetic
resonance imaging applications....Victrex USA
Inc. (West Conshohocken, PA; www.victrex.
com) is celebrating the 30th anniversary of the
inception of the company’s high-temperature,
high-performance polyketone, PEEK polymer....
TricorBraun (St. Louis; www.tricorbraun.com)
has joined the Cooperative Research Consortium
in Packaging Science and Technology. The
consortium provides a forum for industry
representatives to collaborate with California
Polytechnic State University (San Luis
Obispo, CA; www.calpoly.edu) to recommend
research projects that will advance the packaging
industry’s knowledge and practices.... ITW
Switches (Buffalo Grove, IL; www.itwswitches.
com), an Illinois Tool Works company, has
launched a new Web site that provides easier
access to information on the company’s product
lines....Process validation of medical devices,
IQ, OQ, PQ, and ISO standards are a few of
the course topics on the 2009 schedule now
available from the Center for Professional
Advancement (East Brunswick, NJ; www.cfpa.
com)....Sterilization services provider BeamOne
(San Jose, Costa Rica; www.beam-one.com)
has opened an electron-beam medical product
sterilization service center in Alajuela, Costa
Rica....Automation products manufacturer
Omron Electronics (Schaumburg, IL; www.
omron.com) has released the schedule for its
Omron University training courses to be held in
the first quarter of 2009. To reduce travel costs,
students can complete two courses in one week
covering topics such as the design and use of
systems that incorporate motion control, PLCs,
and communications networks.... Altra Industrial
Motion (Braintree, MA; www.altramotion.
com), which produces electromechanical power
transmission products, has launched a Web
site that offers a reference tool for selecting
couplings and provides product information....
LaVezzi Precision (Glendale Heights, IL;
www.lavezzi.com), a manufacturer of high-precision multifaceted medical components,
is celebrating its centennial. Founded in 1908
by an engineer selling sprockets door to door,
the family-owned company has grown to serve
a number of markets, including supplying
titanium components for heart pumps,
orthopedic tools and implants, and a range
of other surgical tools for the medical
industry....Machine tool equipment provider
Mazak Corp. (Florence, KY; www.mazak.
com) has transferred ownership of Northwest
Machine Technologies (Rogers, MN; www.
nwmtec.com), which serves as the distributor
of Mazak products in the Midwest, to two
employees who partnered to purchase the
business. Continuing to operate out of the same
facility, Northwest Machine offers monthly
in-house training events and installation and
implementation services for Mazak equipment.
To access the latest industry
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