Decades after the popular bionic science fiction TV character on The Six Million
Dollar Man, Tel Aviv University researchers have adapted microscopic technology
for bionic body parts and other medical devices.
Tiny sensors and motors
are everywhere, telling your smartphone screen to rotate and your camera to
focus. But now, the TAU team has found a way to print biocompatible components
for these micro-machines, making them ideal for use in bionic arms, for
Microelectromechanical systems, better known as MEMS, are
usually produced from silicon. Engineering doctoral candidates Leeya Engel and
Jenny Shklovsky, under the supervision of Prof. Yosi Shacham-Diamand of the
school of electrical engineering, and Slava Krylov of the school of mechanical
engineering — are creating a novel micro-printing process that uses a highly
flexible and non-toxic organic polymer. The resulting MEMS components can be
more comfortably and safely used in the human body, and use less
As their name suggests, MEMS bridge the worlds of electricity and
mechanics. They have a variety of applications in consumer electronics,
automobiles and medicine. MEMS sensors, like the accelerometer that orients your
smartphone screen vertically or horizontally, gather information from their
surroundings by converting mechanical or chemical signals into electrical
signals. MEMS actuators, which may focus your next smartphone’s camera, work in
the other direction – executing commands by converting electrical signals into
movement. Both types of MEMS depend on micro- and nano-sized components, such as
membranes, either to measure or produce the necessary movement.
years, MEMS membranes, like other MEMS components, were primarily fabricated
from silicon using a set of processes borrowed from the semiconductor industry.
TAU’s new printing process, published in the journal Microelectronic Engineering
and presented at the recent AVS 59th International Symposium in Tampa, Florida,
yields rubbery, paper-thin membranes made of a particular kind of organic
polymer. This material has specific properties that make it attractive for
micro- and nano-scale sensors and actuators. More importantly, the polymer
membranes are more suitable for implantation in the human body than their
silicon counterparts, which partially stems from the fact that they are hundreds
of times more flexible.
The unique properties of the polymer membranes
have unlocked unprecedented possibilities. Their flexibility could help make
MEMS sensors more sensitive and MEMS motors more energy efficient. They could be
key to better cameras and smartphones with a longer battery life, the
But the printing process may bring the biggest benefit
to the field of medicine, where polymer membranes could be used in diagnostic
tests and smart prosthetics. There are already bionic limbs that can respond to
stimuli from an amputee’s nervous system and the external environment, and
prosthetic bladders that regulate urination for people paralyzed below the
waist. Switching to MEMS made with the polymer membranes could help make such
prosthetics more comfortable, efficient and safer for use on or inside the
“The use of new, soft materials in micro devices stretches both the
imagination and the limits of technology,” Engel said, “but introducing polymer
MEMS to industry can be realized only with the development of printing
technologies that allow for low-cost mass production.”
The team’s new
polymer membranes can already be produced quickly and inexpensively. The polymer
base for the membranes was supplied along with a grant by French chemical
“They just gave us the material and asked us to
see what devices we could create with it,” Engel recalled. “This field is like
Legos for grownups.” The next step is to use the printing process to make
functional sensors and actuators almost entirely out of the polymer at the
micro- and nano-scales. Such flexible machines could be put to use in things
like artificial muscles and screens so flexible that you can roll them up and
put them in your pocket.
DOGGED BY YAWNING If you’re a dog owner, you may
be certain there there is a strong emotional bond between you and your pooch.
This may be illustrated by when and how a dog yawns, according to University of
Tokyo research just published in the open-access journal PLoS One.
yawn when they see a person yawning and respond more frequently to their own
owner’s yawns than to a stranger’s, according to researcher Teresa Romero and
Pet dogs in the study watched their owner or a stranger yawn
or fake a yawn. But they yawned significantly more in response to their owners’
actions than to the strangers. The dogs also responded less frequently to the
fake movements, suggesting they have the ability to yawn contagiously when they
see the real thing.
Previous research has shown that dogs yawn in
response to human yawns, but it was unclear whether this was a mild stress
response or an empathetic response. The results of this study suggest the
latter, as dogs responded more to their owners’ genuine yawns than those of a
The researchers observed no significant differences in the
dogs’ heartbeat during the experiments, making it unlikely that their yawns were
a distress response.
Explaining the significance of the results, Romero
says, “Our study suggests that contagious yawning in dogs is emotionally
connected in a way similar to humans. Although our study cannot determine the
exact underlying mechanism operative in dogs, the subjects’ physiological
measures taken during the study allowed us to counter the alternative hypothesis
of yawning as a distress response.