Scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have coaxed polymers to braid themselves into wispy nanoscale ropes that approach the structural complexity of biological materials.
Their work is the latest development in the push to develop self-assembling nanoscale materials that mimic the intricacy and functionality of nature's handiwork, but which are rugged enough to withstand harsh conditions such as heat and dryness.
Although still early in the development stage, their research could lead to new applications that combine the best of both worlds. Perhaps they'll be used as scaffolds to guide the construction of nanoscale wires and other structures. Or perhaps they'll be used to develop drug-delivery vehicles that target disease at the molecular scale, or to develop molecular sensors and sieve-like devices that separate molecules from one another.
Specifically, the scientists created the conditions for synthetic polymers called polypeptoids to assemble themselves into ever more complicated structures: first into sheets, then into stacks of sheets, which in turn roll up into double helices that resemble a rope measuring only 600 nanometers in diameter (a nanometer is a billionth of a meter).
"This hierarchichal self assembly is the hallmark of biological materials such as collagen, but designing synthetic structures that do this has been a major challenge," says Ron Zuckermann, who is the Facility Director of the Biological Nanostructures Facility in Berkeley Lab's Molecular Foundry.
In addition, unlike normal polymers, the scientists can control the atom-by-atom makeup of the ropy structures. They can also engineer helices of specific lengths and sequences. This "tunability" opens the door for the development of synthetic structures that mimic biological materials' ability to carry out incredible feats of precision, such as homing in on specific molecules.
|Contact: Dan Krotz|
DOE/Lawrence Berkeley National Laboratory