Page 37 - Plastics News September 2020

New gel deposition technique

esearchers have developed a unique method for
Rprecisely controlling the deposition of hydrogel,
Researchers at the University of Illinois Chicago have
developed a unique method for precisely controlling the
deposition of hydrogel, which is made of water-soluble
polymers commonly used to support cells in experiments
or for therapeutic purposes. Hydrogel mimics the
extracellular matrix -- the natural environment of cells
in the body. The researchers noticed that their
technique -- which allows for the encapsulation of a
single cell within a minute hydrogel droplet -- can be
used to coax bone marrow stem cells into specialized
cells. Their findings are reported in the journal Advanced
Science. The new technique is an improvement over
existing approaches that often mix much larger amounts
of hydrogel with cells in an uncontrolled manner, which
can make interactions between cells and their
surroundings difficult to study. The new hydrogel Engineering, and corresponding author on the paper.
deposition technique may also be useful for therapeutic According to Shin, the team's deposition technique
purposes, such as for supporting stem cells used to brings the ratio between hydrogels and cells in-line with
create new tissues. "Most experiments use a very high what is seen in the body, and importantly, precisely
amount of hydrogels to interface with cells, which may controls the ratio on a single cell basis. Shin and
not reflect what is happening in the body," said UIC's Jae- colleagues also observed that stem cells in thinner gel
Won Shin, assistant professor of pharmacology and droplets expanded more rapidly than they did in bulk
regenerative medicine at the College of Medicine, and gels.
assistant professor of bioengineering at the College of

Combining silk with synthetic compounds to develop new composite materials
ombining silk, which is safe for use in the human
Cbody, with synthetic compounds, a research team at
the American Chemical Society (ACS) is getting closer to
developing new implantable composite materials with
the best properties of both. "Silk has great potential for
use in biomedical applications," says Juan Guan, Ph.D.,
the project's principal investigator. By combining silk
and synthetic polymers, Guan and her colleagues at
Beihang University are seeking to develop versatile new
materials for use in medicine and, potentially, other
fields as well. While other researchers have already
developed composite materials with silk, they have
typically worked with short fibers or the primary protein
in silk. Guan, however, focuses on silk fabric woven from
a long, single thread. Silkworms' cocoons can contain
fibers nearly 5,000 feet long, and when used whole in with a polymer matrix, often an epoxy, which is used in
fabric, such a fiber can more effectively distribute adhesives. Together, the fabric and the polymer form a
mechanical stress than a series of shorter, discrete ones, laminate -- similar to the durable surface covering found
she says. In their studies, Guan's team uses silk from the on some furniture -- which can then be cut into the
common, domesticated silkworm Bombyx mori, as well shapes the researchers need. The scientists are also
as tougher, more stretchy fibers from the wild species looking to supplement silk with other types of fibers. In a
Antheraea pernyi. The researchers combine this fabric recent study, they added carbon fibers into the mix.

September 2020 37 Plastics News