19 March 2022 | New Scientist | 49mediated by touch,” she says. It also lies at the
heart of our social development. “Touch has a
power unlike that of the other senses,” she says.
Lu is quick to stress that her work with
chemical haptics is not, and in her view never
will be, a replacement for real touch. “Touch
is a really complex sense, which is why using
touch to interact with our world in real life
is such a wonderful experience,” she says.
Instead, she sees it enhancing digital
experiences. “I don’t tend to think of VR
as a vehicle for escaping our reality, but as
a medium that can empower us to do and
experience things we can’t normally.”
And while chemical haptics can replicate
some sensations, others elude it. “I can’t
simulate the softness or texture of my cat’s fur
when I pet her,” says Lu. This is why she and her
team see the most important applications of VR
being experiences and sensations that augment
rather than substitute our day-to-day lives.
Chemical haptics was made possible thanks
to decades of research using natural stimulants.
Next, Lu wants to create new molecules, to
see how they react. If all goes well, it could
even lead to more discoveries about our most
complex sense. “This is the first exploration of
generating skin sensations using an interactive
device that dispenses chemicals,” she says.
“We don’t know how far this can go.” ❚HUMAN^ COMPU
TE
R^ I
NT
EGRA
TION^ LAB/UCHICAG
OAfter finding a protein that
helps our bodies sense cold
(see main story), Ardem
Patapoutian at the Scripps
Research Institute in
California didn’t stop there.
To study how we feel
pressure, Patapoutian and
his colleague Bertrand Coste
designed a new experiment.
After spending the best part
of a year and a half switching
off sensory genes one by
one, Coste identified two
genes that control our body’s
sensitivity to pressure. The
pair called these PIEZO1
and PIEZO2, from the Greekword for “pressure”.
They found that when
they are silenced, it renders
tissues incapable of feeling
force and reduces their
ability to feel pain. The genes
code for proteins that form
ion channels that open in
response to mechanical
pressure on the skin and
internal membranes. They
help our bodies detect blood
pressure, bladder pressure
and breathing. But they play
a much bigger role too.
Proprioception is the
sense of self-movement and
bodily location, sometimeslikened to our body’s GPS.
People without PIEZO2 in
the nerve cells that supply
muscles and tendons tend
to lack coordination and
can end up in a wheelchair.
PIEZO1 and PIEZO2 channels
regulate important
physiological processes,
including blood pressure,
respiration and bladder
control, while PIEZO2 plays
a role in pain-sensing
neurons. Researchers are
now thinking about targeting
force-sensing proteins
with medicines to treat,
for example, chronic pain.UNDER PRESSURE
lidocaine, numbed the skin. Each was pumped
through a wearable device to the skin.
The results were presented at the User
Interface Software and Technology conference
in 2021. In a video of a virtual reality scenario,
someone wearing the chemical haptic system
is seen escaping from a nuclear power plant
on the brink of meltdown. With sparks flying,
sanshool is pumped into channels on the arm
and face to create a feeling of tingling, as if they
were hitting the skin. When the person tries
to unlock a door using an arm-worn interface,
it fails, and lidocaine numbs the area, giving
the impression they have lost the use of the
limb. As the door to the reactor opens and
heat rises, capsaicin flows onto the skin
to simulate the warmth coming from a fire,
and when they exit the power plant and
enter a snowy scene, menthol is released onto
their cheeks to mimic the feel of a cold wind.
While this is the cutting edge, the chemical
pathways involved in touch have been
exploited in various ways before. Medical
creams use concentrated levels of minty
wintergreen oil to create a thermal reaction
on the skin that helps relieve pain. Some
skincare products use capsaicin to promote
blood circulation, and mouthwashes use
menthol to generate a fresh sensation. But
such chemicals have never before been used
in conjunction with virtual worlds.
Not everyone is excited about this
Victoria Woollaston is a
freelance journalist based
in Buckinghamshire, UKdevelopment. “Honestly, it scares me,” says
Francis McGlone, a neuroscientist at Liverpool
John Moores University in the UK. He has
spent decades studying the social importance
of touch to humans (see “Emotional touch”,
left) and believes virtual reality will never be
able to replicate this. “We know that this digital
world is going to take over,” he says, “but we
need to find ways to ameliorate the negative
consequences of not having physical contact.”
“Touch is a matter of life and death,” says
Katerina Fotopoulou at University College
London. Compared with other mammals,
humans can do very little when we are born.
“Our very survival in those early days relies
on caregiving from our parents and all of this isA new haptic system pumps
chemicals onto the skin to
provide virtual sensations