Nanoscopic static electricity generates chiral patterns

Feb 02, 2009

In the tiny world of amino acids and proteins and in the helical shape of DNA, a biological phenomenon abounds.

These objects are all chiral — they cannot exactly superimpose their mirror image by translation or rotation. A common example of this is human hands — a right hand cannot superimpose itself into its mirror image, a left hand. This description of a molecule's symmetry (or lack thereof) is important in determining the molecule's properties in chemistry.

But while scientists and engineers know that at the sub-atomic level weak forces are chiral, how these electrostatic forces can generate a chiral world is still a mystery.

Researchers at Northwestern University in the group of Monica Olvera de la Cruz, professor of materials science and engineering and chemical and biological engineering at the McCormick School of Engineering and Applied Science, have recently shown how electrostatic interactions — commonly known as static electricity — alone can give rise to helical shapes. The group has constructed a mathematical model that can capture all possible regular shapes chiral objects could have, and they computed the preferred arrangements induced by electrostatic interactions.

Their work will be published as the cover story in the journal Soft Matter and is published online.

"In this way we are simply letting nature tell us how it would like to be, and we generalize it to many different systems," Olvera de la Cruz says." She and her colleagues report that chirality can only spontaneously arise as a consequence of electrostatic interactions and does not require the presence of other more complicated interactions, like dipolar or short-range van der Waals interactions.

Their model also describes arrangement of DNA mixed with carbon nanotubes. DNA has been shown to form helices around nanotubes, thereby separating the different types of carbon nanotubes into families.

The research findings concur with previous research using microscopy.

"From our predicted helical shapes of DNA wrapped around carbon nanotubes, we found amazing correspondence to those that were recently measured by atomic force microscopy," Olvera de le Cruz says.

The work shows that electrostatics is a pathway for understanding how nature generates helical symmetries. Researchers hope that future work can show how to use simple interactions to generate other symmetries that drive complex phenomena.

Source: Northwestern University

Explore further: Nanocontainers for nanocargo: Delivering genes and proteins for cellular imaging, genetic medicine and cancer therapy

add to favorites email to friend print save as pdf

Related Stories

22 elephants poached in Mozambique in two weeks

4 hours ago

Poachers slaughtered 22 elephants in Mozambique in the first two weeks of September, environmentalists said Monday, warning that killing for ivory by organised syndicates was being carried out on an "industrialised" ...

Recommended for you

Engineers show light can play seesaw at the nanoscale

14 hours ago

University of Minnesota electrical engineering researchers have developed a unique nanoscale device that for the first time demonstrates mechanical transportation of light. The discovery could have major ...

Engineered proteins stick like glue—even in water

Sep 21, 2014

Shellfish such as mussels and barnacles secrete very sticky proteins that help them cling to rocks or ship hulls, even underwater. Inspired by these natural adhesives, a team of MIT engineers has designed ...

Smallest possible diamonds form ultra-thin nanothreads

Sep 21, 2014

For the first time, scientists have discovered how to produce ultra-thin "diamond nanothreads" that promise extraordinary properties, including strength and stiffness greater than that of today's strongest ...

A nanosized hydrogen generator

Sep 20, 2014

(Phys.org) —Researchers at the US Department of Energy's (DOE) Argonne National Laboratory have created a small scale "hydrogen generator" that uses light and a two-dimensional graphene platform to boost ...

User comments : 0