Page 46 - Plastics News September 2021

TECHNoLoGY

Polymers 'Click' Together Using Green that they become interlocked. Even

Chemistry though the polymers are not chemically
bonded, they cannot be pulled apart
and form a new material with properties
multi-institutional team of chemists could be used as a hub to link together greater than the simple sum of its parts.
A harnessed the power of a dangerous diverse components into a modular Traditional methods for manufacturing
gas called SOF4 to create new modifiable family of new and potentially valuable sIPNs typically involve producing the
materials. Even more importantly, the constituent parts called monomers
scientists found that the reactions could and mixing them together in the
be done in an environmentally safe way right chemical conditions to control
without dangerous solvents and polluting their assembly into large networks
byproducts a form of what chemists call in a process called polymerization.
"click chemistry." Click chemistry allows "When it works, it's a fantastic
users to "click" together two molecules platform that can incorporate different
with precision, speed, and reliability. The functionalities into the self-assembled
team used SOF4 to form long chains layer for biomedical or environmental
polymers useful for drug discovery polymers with room for important applications," said Lingchong You,
and material science. The team used modifications. Moses says, "That's why professor of biomedical engineering at
a type of rapid and reliable chemistry click chemistry is great, really! As long Duke. "But the process is often not as
known as click chemistry to 'click' these as we have the gas, we could do all that biocompatible as you might want. So
molecules together without producing chemistry in one day, make a polymer, we thought why not use living cells to
toxic byproducts. SOF4 is a gas that was and post-modify it in one day. That's synthesize the second layer to make it as
discovered over a hundred years ago incredibly fast." This new chemistry will biocompatible as possible?" In the new
but is rarely used because it is difficult allow scientists to generate a vast new paper, Zhuojun Dai, a former postdoc
to prepare and highly reactive. Now library of polymers, each with its own in the You lab who is now an associate
a collaboration of chemists including distinct properties and applications in professor at the Shenzhen Institute
Cold Spring Harbor Laboratory drug discovery and material science. of Synthetic Biology, uses a platform
(CSHL) Professor John E. Moses, that the lab has been developing for
Nobel laureate K. Barry Sharpless and several years called "swarmbots" to do
Associate Professor Peng Wu, both of Cells Construct Living just that. Nobody has used living cells
Scripps Research, and Han Zuilhof of Composite Polymers as a factory to produce monomers in
Wageningen University found a way
to use the molecule safely as building iomedical engineers at Duke
blocks for new products. In a paper in BUniversity have demonstrated
Nature Chemistry, they describe a new that a class of interwoven composite
set of modifiable polymers made from materials called semi-interpenetrating
SOF4. It was a team effort to tame the polymer networks (sIPNs) can be
molecule. Zuilhof says, "The goals of the produced by living cells. The approach
various research groups were different, could make these versatile materials
but we combined all our expertise to
achieve our many goals." Suhua Li, the more biologically compatible for
lead author of the study and a former biomedical applications such as time-
postdoc in Sharpless' lab, started with a delayed drug delivery systems. The
tiny container of the gas in the lab, but concept of sIPNs has been around for
after he used that up, he says, "there was more than 100 years and has been used real-time for sIPNs before. The proof-
no more SOF4 available anywhere in the in automotive parts, medical devices, of-principle demonstration shows that,
world. The great potential of the SOF4 molding compounds and engineering not only can we fabricate these types
chemistry inspired me to make the gas plastics. The general idea is for one of functional materials with live cells,
by myself, even though the procedure or more polymers to assemble around but they can exhibit medically relevant
seemed dangerous." The SOF4 molecule another polymer scaffold in such a way functions.

46 PLASTICS NEWS SEPTEMBER 2021 47 PLASTICS NEWS SEPTEMBER 2021