Medical Design Briefs - February 2022 - 22

unit cells with naturally stable joints,
building 2D and 3D structures from
individual totimorphic cells.
The researchers used both mathematResearchers
from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS)
have developed a shape-shifting material that can take and hold any possible shape, paving the way
for a new type of multifunctional material that could be used in a range of applications, from robotics
and biotechnology to architecture. (Credit: Harvard SEAS)
tion of rigid and elastic elements balances
the energy of the cells, making
each neutrally stable, meaning that they
can transition between an infinite number
of positions or orientations and be
stable in any of them.
" By having a neutrally stable unit cell
we can separate the geometry of the
material from its mechanical response
at both the individual and collective
level, " says Gaurav Chaudhary, a postdoctoral
fellow at SEAS and co-first
author of the paper. " The geometry of
the unit cell can be varied by changing
both its overall size as well as the length
of the single movable strut, while its
elastic response can be changed by varying
either the stiffness of the springs
within the structure or the length of the
struts and links. "
The researchers dubbed the assembly
as totimorphic materials because of their
ability to morph into any stable shape.
The researchers connected individual
ical modeling and real-world demonstrations
to show the material's shape-shifting
ability. The team demonstrated that
one single sheet of totimorphic cells can
curve up, twist into a helix, morph into
the shape of two distinct faces, and even
bear weight.
" We show that we can assemble these
elements into structures that can take on
any shape with heterogeneous mechanical
responses, " says S. Ganga Prasath, a
postdoctoral fellow at SEAS and co-first
author of the paper. " Since these materials
are grounded in geometry, they
could be scaled down to be used as sensors
in robotics or biotechnology or
could be scaled up to be used at the
architectural scale.
" All together, these totimorphs pave
the way for a new class of materials whose
deformation response can be controlled
at multiple scales, " says Mahadevan.
The research was co-authored by
Edward Soucy.
This article was written by Leah Burrows,
Harvard University. For more information, visit
www.seas.harvard.edu. A video of the technology
is available at https://www.youtube.com/
watch?v=9JWPUC1L4mQ&feature=emb_logo.
Silicone Nanochip Can Reprogram Biological Tissue in
Living Body
The noninvasive nanochip
applies a harmless
electric spark to deliver
specific genes in a fraction
of a second.
Indiana University
Bloomington, IN
A silicone device that can change skin
tissue into blood vessels and nerve cells
has advanced from prototype to standardized
fabrication, meaning it can
now be made in a consistent, reproducible
way. As reported in Nature
Protocols, this work, developed by re -
searchers at the Indiana University
School of Medicine, takes the device one
step closer to potential use as a treatment
for people with a variety of health
concerns.
22
Cov
The technology, called tissue nano -
transfection, is a noninvasive nanochip
device that can reprogram tissue function
by applying a harmless electric
spark to deliver specific genes in a fraction
of a second. In laboratory studies,
the device successfully converted skin tissue
into blood vessels to repair a badly
injured leg. The technology is currently
being used to reprogram tissue for different
kinds of therapies, such as repairing
brain damage caused by stroke or
preventing and reversing nerve damage
caused by diabetes.
" This report on how to exactly produce
these tissue nanotransfection chips
will enable other researchers to participate
in this new development in regenerative
medicine, " says Chandan Sen,
director of the Indiana Center for
Regenerative Medicine and Engi neer -
ing, associate vice president for research
www.medicaldesignbriefs.com
ToC
and distinguished professor at the IU
School of Medicine.
Sen also leads the regenerative medicine
and engineering scientific pillar of
the IU Precision Health Initiative and is
lead author on the publication.
" This small silicone chip enables nanotechnology
that can change the function
of living body parts, " he says. " For
example,
if someone's blood vessels
were damaged because of a traffic accident
and they need blood supply, we
can't rely on the pre-existing blood vessel
anymore because that is crushed, but
we can convert the skin tissue into blood
vessels and rescue the limb at risk. "
" This is about the engineering and
manufacturing of the chip, " he says.
" The chip's nanofabrication process typically
takes five to six days and, with the
help of this report, can be achieved by
anyone skilled in the art. "
Medical Design Briefs, February 2022

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Medical Design Briefs - February 2022

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