Navigation Links
Chemists become molecular sculptors, synthesizing tiny, molecular traps
Date:12/5/2011

BUFFALO, N .Y. -- Using clever but elegant design, 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.

In addition, because UB scientists construct the tubes from scratch, they can create traps of different sizes that snare molecular prey of different sizes. The level of fine tuning possible is remarkable: In the Journal of the American Chemical Society, the researchers report that they were able to craft nanotubes that captured particles 2.8 nanometers in diameter, while leaving particles just 1.5 nanometers larger untouched.

These kinds of cages could be used, in the future, to expedite tedious tasks, such as segregating large quantum dots from small quantum dots, or 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, the UB assistant professor of chemistry who led the research.

"Just like a contractor wants tile squares or bricks to be the same size so they fit well together, 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," Rzayev said.

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 trapa 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. (As in a tequila sunrise, the thinner, water-based solution floats on top of the denser chloroform solution, with little mixing.)

When the scientists shook the cocktail for five minutes, the nanotubes collided with and trapped the dyes, bringing the dyes into the chloroform solution. (The dyes, on their own, do not dissolve in chloroform.)

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.

The research on nanotubes is part of a larger suite of studies Rzayev is conducting on bottle-brush molecules using a National Science Foundation CAREER award. His other work includes the fabrication of bottle-brush-based nanomembranes that could be adapted for water filtration, and the assembly of layered, bottle-brush polymers that reflect visible light like the wings of a butterfly do.


'/>"/>

Contact: Charlotte Hsu
chsu22@buffalo.edu
716-645-4655
University at Buffalo
Source:Eurekalert

Related biology technology :

1. Northwestern chemists take gold, mass-produce Beijing Olympic logo
2. TIBCO Speeds Drug Discovery for Chemists
3. Brown chemists create more efficient palladium fuel cell catalysts
4. Spectrum Blue Steel partners with Famous Chemists for Procuring Profitable Applications from Garbage Using the Biosphere MKV and Electrostatic Precipitators
5. Brown chemists report promising advance in fuel-cell technology
6. University of Toronto chemists make breakthrough in nanoscience research
7. IU chemists develop new light switch chloride binder
8. Metal-mining bacteria are green chemists
9. UCLA chemists, engineers achieve world record with high-speed graphene transistors
10. UC San Diego chemists produce first high-resolution RNA nano square
11. Chemists create molecular polyhedron -- and potential to enhance industrial and consumer products
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... , June 27, 2016 /PRNewswire/ - BIOREM Inc. (TSX-V: ... been advised by its major shareholders, Clean Technology Fund ... United States based venture capital funds ... of Biorem (on a fully diluted, as converted basis), ... disposition of their entire equity holdings in Biorem to ...
(Date:6/27/2016)... NC (PRWEB) , ... June 27, 2016 , ... ... just published their findings on what they believe could be a new and ... of the new research. Click here to read it now. , ...
(Date:6/27/2016)... ... June 27, 2016 , ... Newly created ... and solutions to the healthcare market. The company's primary focus is on new ... and marketing strategies that are necessary to help companies efficiently bring their products ...
(Date:6/27/2016)... , June 27, 2016  Liquid Biotech ... the funding of a Sponsored Research Agreement with ... tumor cells (CTCs) from cancer patients.  The funding ... CTC levels correlate with clinical outcomes in cancer ... data will then be employed to support the ...
Breaking Biology Technology:
(Date:6/3/2016)... June 3, 2016 ... Nepal hat ein ... hochsicherer geprägter Kennzeichen, einschließlich Personalisierung, Registrierung und ... der Produktion und Implementierung von Identitätsmanagementlösungen. Zahlreiche ... im Januar teilgenommen, aber Decatur wurde als ...
(Date:6/2/2016)... 2016 Perimeter Surveillance & Detection ... Physical Infrastructure, Support & Other Service  The ... offers comprehensive analysis of the global Border Security ... revenues of $17.98 billion in 2016. Now: ... leader in software and hardware technologies for advanced video ...
(Date:5/20/2016)...  VoiceIt is excited to announce its new ... By working together, VoiceIt and VoicePass will offer ... take slightly different approaches to voice biometrics, collaboration ... usability. Both ... "This marketing and technology partnership allows ...
Breaking Biology News(10 mins):