Media

Synthesis of tiny, molecular cages to capture and purify nanomaterials

8:20 PM, 6th December 2011
Synthesis of tiny, molecular cages to capture and purify nanomaterials
The green structures are negatively charged carboxylic acid groups, which help trap positively charged particles.

NEW YORK, US: University at Buffalo chemists have synthesized tiny, molecular cages that can be used to capture and purify nanomaterials.

Sculpted from a special kind of molecule called a "bottle-brush molecule," the traps consist of tiny, organic tubes whose interior walls carry a negative charge. This feature enables the tubes to selectively encapsulate only positively charged particles.

The nanotubes captured particles 2.8 nanometers in diameter, while leaving particles just 1.5 nanometers larger untouched.

These kinds of cages could be used to expedite tedious tasks, such as separating proteins by size and charge.

"The shapes and sizes of molecules and nanomaterials dictate their utility for desired applications. Our molecular cages will allow one to separate particles and molecules with pre-determined dimensions, thus creating uniform building blocks for the fabrication of advanced materials," said Javid Rzayev, assistant professor of chemistry, University of Buffalo.

“Scientists are eager to produce nanometer-size particles with the same dimensions, which can go a long way toward creating uniform and well-behaved materials," said Rzayev.

To create the traps, Rzayev and his team first constructed a special kind of molecule called a bottle-brush molecule. These resemble a round hair brush, with molecular "bristles" protruding all the way around a molecular backbone.

After stitching the bristles together, the researchers hollowed out the center of each bottle-brush molecule, leaving behind a structure shaped like a toilet paper tube.

The carving process employed simple but clever chemistry: When building their bottlebrush molecules, the scientists constructed the heart of each molecule using molecular structures that disintegrate upon coming into contact with water. Around this core, the scientists then attached a layer of negatively charged carboxylic acid groups.

To sculpt the molecule, the scientists then immersed it water, in effect hollowing the core. The resulting structure was the trap—a nanotube whose inner walls were negatively charged due to the presence of the newly exposed carboxylic acid groups.

To test the tubes' effectiveness as traps, Rzayev and colleagues designed a series of experiments involving a two-layered chemical cocktail.

The cocktail's bottom layer consisted of a chloroform solution containing the nanotubes, while the top layer consisted of a water-based solution containing positively charged dyes. When the scientists shook the cocktail for five minutes, the nanotubes collided with and trapped the dyes, bringing the dyes into the chloroform solution. In similar experiments, Rzayev and his team were able to use the nanotubes to extract positively charged molecules called dendrimers from an aqueous solution. The nanotubes were crafted so that dendrimers with a diameter of 2.8 nanometers were trapped, while dendrimers that were 4.3 nanometers across were left in solution.

To remove the captured dendrimers from the nanotubes, the researchers simply lowered the pH of the chloroform solution, which shuts down the negative charge inside the traps and allows the captured particles to be released from their cages.

© University at Buffalo News

0 Comments

Login

Your Comments (Up to 2000 characters)
Please respect our community and the integrity of its participants. WOC reserves the right to moderate and approve your comment.

Related News


Belarus Potash sign MOP delivery contracts in China

MINSK, BELARUS: JSC Belarusian Potash Company  has signed a contract with the largest Chinese importers of mineral fertilizers, Sinochem and CNAM ...

Read more
M&G selects Corpus Christi, Texas site to build its new PET/PTA plants

HOUSTON, US: Mossi & Ghisolfi Group (M&G) has selected Corpus Christi, Texas, as the location for construction of its previously announced pol ...

Read more
Dow, Dragon Crown to jointly build chemical terminal in China

WANCHAI, HONG KONG: Dow and Dragon Crown Group signed a memorandum of understanding (MOU) on 8 July 2011 with the intent to form a joint venture com ...

Read more
Lonza to acquire Arch Chemicals for $1.4 billion

Lonza and Arch Chemicals announce an agreement for Lonza to acquire all of the outstanding shares of Arch Chemicals for $47.20 per share in cash. O ...

Read more
Dr Reddy’s work on protein crystallisation published in PNAS

  SURREY, UNITED KINGDOM: A new technique developed by Dr Reddy for crystallising proteins has been published in the Proceedings of the National ...

Read more
Researchers closer to understanding cell-division gatekeeper enzyme

  BLACKSBURG, US: An enzyme called Pin1 regulates the protein that initiates cell division by changing the shape of a peptide bond. Researchers ...

Read more
Copyright © 2014. Kimberlite Softwares Pvt. Ltd., India. All rights reserved.
World of Chemicals.