Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Beautiful "flowers" self-assemble in a beaker: Elaborate nanostructures blossom from a chemical reaction perfected at Harvard

These false-color SEM images reveal microscopic flower structures created by manipulating a chemical gradient to control crystalline self-assembly.Image courtesy of Wim L. Noorduin
These false-color SEM images reveal microscopic flower structures created by manipulating a chemical gradient to control crystalline self-assembly.

Image courtesy of Wim L. Noorduin

Abstract:
"Spring is like a perhaps hand," wrote the poet E. E. Cummings: "carefully / moving a perhaps / fraction of flower here placing / an inch of air there... / without breaking anything."

With the hand of nature trained on a beaker of chemical fluid, the most delicate flower structures have been formed in a Harvard laboratory—and not at the scale of inches, but microns.

Beautiful "flowers" self-assemble in a beaker: Elaborate nanostructures blossom from a chemical reaction perfected at Harvard

Cambridge, MA | Posted on May 17th, 2013



Home
About SEAS
Academics
Faculty & Research
News & Events
Calendars & Colloquia
Videos
Publications
K-12 & Community Programs
For the Media
Press Releases
Beautiful "flowers" self-assemble in a beaker
Administration

Quick Links

Library
Directory
Map & Directions
Faculty & Staff Intranet

Beautiful "flowers" self-assemble in a beaker

May 16, 2013

Elaborate nanostructures blossom from a chemical reaction perfected at Harvard

CONTACT: Caroline Perry, (617) 496-1351

Flower collage

These false-color SEM images reveal microscopic flower structures created by manipulating a chemical gradient to control crystalline self-assembly. (Image courtesy of Wim L. Noorduin.)

Cambridge, Mass. - May 16, 2013 - "Spring is like a perhaps hand," wrote the poet E. E. Cummings: "carefully / moving a perhaps / fraction of flower here placing / an inch of air there... / without breaking anything."

With the hand of nature trained on a beaker of chemical fluid, the most delicate flower structures have been formed in a Harvard laboratory—and not at the scale of inches, but microns.

These minuscule sculptures, curved and delicate, don't resemble the cubic or jagged forms normally associated with crystals, though that's what they are. Rather, fields of carnations and marigolds seem to bloom from the surface of a submerged glass slide, assembling themselves a molecule at a time.

By simply manipulating chemical gradients in a beaker of fluid, Wim L. Noorduin, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS) and lead author of a paper appearing on the cover of the May 17 issue of Science, has found that he can control the growth behavior of these crystals to create precisely tailored structures.

"For at least 200 years, people have been intrigued by how complex shapes could have evolved in nature. This work helps to demonstrate what's possible just through environmental, chemical changes," says Noorduin.

The precipitation of the crystals depends on a reaction of compounds that are diffusing through a liquid solution. The crystals grow toward or away from certain chemical gradients as the pH of the reaction shifts back and forth. The conditions of the reaction dictate whether the structure resembles broad, radiating leaves, a thin stem, or a rosette of petals.

It is not unusual for chemical gradients to influence growth in nature; for example, delicately curved marine shells form from calcium carbonate under water, and gradients of signaling molecules in a human embryo help set up the plan for the body. Similarly, Harvard biologist Howard Berg has shown that bacteria living in colonies can sense and react to plumes of chemicals from one another, which causes them to grow, as a colony, into intricate geometric patterns.

Replicating this type of effect in the laboratory was a matter of identifying a suitable chemical reaction and testing, again and again, how variables like the pH, temperature, and exposure to air might affect the nanoscale structures.

The project fits right in with the work of Joanna Aizenberg, an expert in biologically inspired materials science, biomineralization, and self-assembly, and principal investigator for this research.

Aizenberg is the Amy Smith Berylson Professor of Materials Science at Harvard SEAS, Professor of Chemistry and Chemical Biology in the Harvard Department of Chemistry and Chemical Biology, and a Core Faculty Member of the Wyss Institute for Biologically Inspired Engineering at Harvard.

Her recent work has included the invention of an extremely slippery material, inspired by the pitcher plant, and the discovery of how bacteria use their flagella to cling to the surfaces of medical implants.

"Our approach is to study biological systems, to think what they can do that we can't, and then to use these approaches to optimize existing technologies or create new ones," says Aizenberg. "Our vision really is to build as organisms do."

To create the flower structures, Noorduin and his colleagues dissolve barium chloride (a salt) and sodium silicate (also known as waterglass) into a beaker of water. Carbon dioxide from air naturally dissolves in the water, setting off a reaction which precipitates barium carbonate crystals. As a byproduct, it also lowers the pH of the solution immediately surrounding the crystals, which then triggers a reaction with the dissolved waterglass. This second reaction adds a layer of silica to the growing structures, uses up the acid from the solution, and allows the formation of barium carbonate crystals to continue.

"You can really collaborate with the self-assembly process," says Noorduin. "The precipitation happens spontaneously, but if you want to change something then you can just manipulate the conditions of the reaction and sculpt the forms while they're growing."

Increasing the concentration of carbon dioxide, for instance, helps to create 'broad-leafed' structures. Reversing the pH gradient at the right moment can create curved, ruffled structures.

Noorduin and his colleagues have grown the crystals on glass slides and metal blades; they've even grown a field of flowers in front of President Lincoln's seat on a one-cent coin.

"When you look through the electron microscope, it really feels a bit like you're diving in the ocean, seeing huge fields of coral and sponges," describes Noorduin. "Sometimes I forget to take images because it's so nice to explore."

In addition to her roles at Harvard SEAS, the Department of Chemistry and Chemical Biology, and the Wyss Institute, Joanna Aizenberg is Director of the Kavli Institute for Bionano Science and Technology at Harvard and Director of the Science Program at the Radcliffe Institute for Advanced Study.

Coauthors included Alison Grinthal, a research scientist at Harvard SEAS, and L. Mahadevan, who is the Lola England de Valpine Professor of Applied Mathematics at SEAS, Professor of Organismic and Evolutionary Biology and of Physics, and a Core Faculty Member at the Wyss Institute.

The project was supported by National Science Foundation grants to the Harvard Materials Research Science and Engineering Center (DMR-0820484) and the Harvard Center for Nanoscale Systems (ECS-0335765); and by the Netherlands Organization for Scientific Research.

####

For more information, please click here

Contacts:
Caroline Perry
(617) 496-1351

Copyright © Harvard's School of Engineering and Applied Sciences (SEAS)

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Imaging

New Grand ARM Transmission Electron Microscope Offers Highest Commercially-Available Atomic Resolution of 63 Picometers October 17th, 2014

Nanotronics Imaging Releases nSPEC® 3D, Powerful Microscope That Captures 3D Images at Nanoscale, in Lightning Speed: Company Unveils Design at American Chemical Society 2014 International Elastomer Conference October 14th, 2014

BSA Distinguished Lecture Today, 10/14: 'LCLS: A Stunning New View Through X-ray Laser Eyes' October 14th, 2014

The Körber Foundation congratulates Stefan Hell on winning the 2014 Nobel Prize October 10th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

HP Supercomputer at NREL Garners Top Honor October 19th, 2014

First Canada Excellence Research Chair gets $10 million from the federal government for oilsands research at the University of Calgary: Federal government announces prestigious research chair to study improving oil production efficiency October 19th, 2014

Self Assembly

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

New Topical Hemostatic Agent: Neutral Self-Assembling Peptide Hydrogel September 30th, 2014

Big Results Require Big Ambitions: Three young UCSB faculty receive CAREER awards from the National Science Foundation September 18th, 2014

Rice rolls 'neat' nanotube fibers: Rice University researchers' acid-free approach leads to strong conductive carbon threads September 15th, 2014

Discoveries

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Announcements

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Tools

New Grand ARM Transmission Electron Microscope Offers Highest Commercially-Available Atomic Resolution of 63 Picometers October 17th, 2014

Nanodevices for clinical diagnostic with potential for the international market: The development is based on optical principles and provides precision and allows saving vital time for the patient October 15th, 2014

Nanotronics Imaging Releases nSPEC® 3D, Powerful Microscope That Captures 3D Images at Nanoscale, in Lightning Speed: Company Unveils Design at American Chemical Society 2014 International Elastomer Conference October 14th, 2014

Unique catalysts for hydrogen fuel cells synthesized in ordinary kitchen microwave oven October 14th, 2014

Grants/Awards/Scholarships/Gifts/Contests/Honors/Records

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

QD Vision Wins Prestigious Presidential Green Chemistry Challenge Award from the U.S. Environmental Protection Agency October 16th, 2014

Beyond LEDs: Brighter, new energy-saving flat panel lights based on carbon nanotubes - Planar light source using a phosphor screen with highly crystalline single-walled carbon nanotubes (SWCNTs) as field emitters demonstrates its potential for energy-efficient lighting device October 14th, 2014

Unique catalysts for hydrogen fuel cells synthesized in ordinary kitchen microwave oven October 14th, 2014

NanoNews-Digest
The latest news from around the world, FREE





  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE