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nanotimes

Research

10-04 :: April 2010

Materials //

Berkeley Lab Scientists Create ‘Molecular Paper’

B

erkeley Lab scientists have made the largest

two-dimensional polymer crystal self-assem-

bled in water to date. This entirely new material mirrors the structural complexity of biological systems with the durable architecture needed for membranes or integration into functional devices.

These self-assembling sheets are made of peptoids, engineered polymers that can flex and fold like pro- teins while maintaining the robustness of manmade materials. Each sheet is just two molecules thick yet hundreds of square micrometers in area – akin to ‘molecular paper’ large enough to be visible to the naked eye. What’s more, unlike a typical polymer, each building block in a peptoid nanosheet is en- coded with structural ‘marching orders’ – suggesting its properties can be precisely tailored to an applica- tion. For example, these nanosheets could be used to control the flow of molecules or serve as a platform for chemical and biological detection.

“Our findings bridge the gap between natural biopo- lymers and their synthetic counterparts, which is a fundamental problem in nanoscience,” said Ronald Zuckermann, Director of the Biological Nanostruc- tures Facility at the Molecular Foundry. “We can now translate fundamental sequence information from proteins to a non-natural polymer, which results in a robust synthetic nanomaterial with an atomical- ly-defined structure.”

These fluorescence microscope images show free-floating peptoid nanosheets in liquid. Each peptoid sheet is just two molecules thick yet up to hundreds of square micro- meters in area – a ‘molecular paper’ large enough to be visible to the naked eye.

The building blocks for peptoid polymers are cheap, readily available and generate a high yield

of product, providing a huge advantage over other synthesis techniques. Zuckermann, instrumental in developing the Foundry’s one- of-a-kind robotic syn- thesis capabilities, worked with his team of coauthors to form libraries of peptoid materials. After screening many candidates, the team landed upon the unique combination of polymer building blocks that sponta- neously formed peptoid nanosheets in water.