DNA design brings predictability to polymer gels

Date:
February 16, 2022
Source:
Hokkaido University
Summary:
Simulations have led to the fabrication of a polymer-DNA gel that
could be used in tissue regeneration and robotics.



FULL STORY ========================================================================== Simulations have led to the fabrication of a polymer-DNA gel that could
be used in tissue regeneration and robotics.


========================================================================== Scientists in Japan have made a tuneable, elastic and
temperature-sensitive gel by using complementary DNA strands to connect star-shaped polymer molecules together. The gel, and the method used to
develop it, could lead to advances in tissue regeneration, drug delivery
and soft robotics. Xiang Li at Hokkaido University led the team of
researchers who reported their findings in the journal Polymer Science.

Scientists have long been looking for better ways to develop gels that
can be used in a variety of applications, including in the fields of
medicine and engineering. Ideally, such gels need to be predictable in
their behaviour, self-healing and durable enough for the rigorous jobs
they are intended for.

"Gels are made by using bonds to link polymer molecules together,"
explains Li.

"When the bonds are connected, the material is more solid, and when they
break in response to stress, the material turns to liquid." Owing to
their high biocompatibility, water solubility and temperature sensitivity,
DNA strands would be highly suitable for linking polymer molecules by
taking advantage of their ability to form complementary bonds. However, scientists have so far found it difficult to use DNA links to develop homogeneous gels with on-demand elastic properties.

Looking to solve this problem, Li and his colleagues used software
programs to simulate the formation of different DNA sequences and their complementary strands, and to determine how these double strands respond
to changes in temperature. Their aim was to identify complementary DNA sequences that would only disconnect above 63DEGC in order to ensure a potential gel's stability in the human body.

Based on the software simulations, they chose a pair of complementary DNA sequences to link four-armed molecules of polyethylene glycol (PEG). They prepared the gel by dissolving DNA strands and PEG separately in buffer solutions before mixing them in a test tube immersed in a hot water bath
that was then cooled to ambient temperature. Finally, they conducted
a series of experiments and analyses to evaluate the resulting gel's properties.

The gel performed as predicted by the simulations, remaining elastic,
self- repairing and solid until its melting temperature of 63DEGC
over multiple testing cycles. The experiments also showed that the PEG molecules were homogeneously linked together by the DNA double strands
and that liquid formation happened when the strands separated.

"Our findings suggest that we will be able to fabricate DNA gels with
on-demand viscoelastic properties by making use of already available
data on DNA thermodynamics and kinetics," says Li. "The aim will be
to improve the understanding and applications of this class of gel." ========================================================================== Story Source: Materials provided by Hokkaido_University. Note: Content
may be edited for style and length.


========================================================================== Related Multimedia:
* The_star-polymer-DNA-gel_liquifies_when_its_temperature_is_increased ========================================================================== Journal Reference:
1. Masashi Ohira, Takuya Katashima, Mitsuru Naito, Daisuke Aoki, Yusuke
Yoshikawa, Hiroki Iwase, Shin‐ichi Takata, Kanjiro Miyata,
Ung‐il Chung, Takamasa Sakai, Mitsuhiro Shibayama, Xiang Li.

Star‐Polymer-DNA Gels Showing Highly Predictable and Tunable
Mechanical Responses. Advanced Materials, 2022; 2108818 DOI:
10.1002/ adma.202108818 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220216083003.htm

--- up 10 weeks, 4 days, 7 hours, 13 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)