DISCOVERIESA team of scientistsbasedintheUS
have transformed stemcellstakenfrom
frog embryos into livingrobots.These
millimetre-wide globscanmovetowards
a target, pick up a payloadsuchasa
medicine that needstobetakentoa
specific place insidea patient,andeven
heal themselves afterbeingcut.
Dubbed ‘xenobots’,thenewlifeforms
were designed usinga supercomputerby
scientists at the UniversityofVermont
and then assembledandtestedby
biologists at Tufts University.
“These are novel living machines,”
said research co-leader Prof Joshua
Bongard, of the University of Vermont’s
Morphology, Evolution & Cognition
Laboratory. “They’re neither a traditional
robot nor a known species of animal.
It’s a new class of artifact: a living,
programmable organism.”
The team at Vermont used the Deep
Green supercomputer cluster to run
an evolutionary algorithm that was
given a simple task to achieve, such as
locomotion in one direction, to create
thousands of potential designs for the
News
in brief
new life forms. Anyfailed designs were
ruled out, while the more promising
ones were refined further. The most
successful designs were selected for
testing by the team at Tufts.
The Tufts team harvested heart and
skin stem cells from the embryos of
African clawed frogs, Xenopus laevis,
and used tiny forceps to arrange them
into the designs specified by the
computer modelling work. As heart cells
can expand and contract, they acted as
tiny motors to enable the newly createdorganismstomovearoundintheir
environment.Inlatertests,thexenobots
wereabletomoveincircles,push
pelletsintoa chosenlocation,andcarry
arounda smallpayloadina specially
designedpouch.Theywerealsoableto
self-healafterbeingcut.
Thexenobotscouldbeputtoa
numberofuses,suchascleaningup
pollutionfromtheoceans,ortargeted
drugdeliverysystems.Thoughthework
is stillata relativelyearlystage,the
researcherssaytheyareawareofthe
ethical questions that could arise in
the future, particularly if the xenobots’
cognitive abilities are increased.
“If humanity is going to survive
into the future, we need to better
understand how complex properties,
somehow, emerge from simple rules,”
said Prof Michael Levin, the director
of the Center for Regenerative and
Developmental Biology at Tufts. “I think
it’s an absolute necessity for society
going forward to get a better handle
on systems where the outcome is very
complex,” he added.1 One of the
frogbot designs
discovered by the
evolutionary
algorithm
2 The physical
organism, built
completely from
biological tissue
(red for heart cells,
green for skin
cells)PEOPLE ON LOW-INCOMES HAVE
WORSE HEALTH NOW THAN
PREVIOUS GENERATIONS
Despite improvements in healthcare, the
poorest in society have more long-term
conditions now than those who were born
100 years ago, a study at University College
London has found. Using data from a
pre-existing survey of 200,000 people aged30 to 59 in England, researchers determined
that the inequality between the health of
the poorest and the richest had increased
over the years. They compared the health of
people born in 1920-22 with those born
1968-70 and found that long-term illnesses
had grown twice as prevalent in
low-income women, and one and a half
times as prevalent in low-income men.“ ey’re neither a
traditional robot nor
a known species of
animal. It’s a living,
programmable
organism”
1 2