Chemists at Rice University have discovered how to assemble gold and silver nanoparticle building blocks into larger structures based on a novel method that harkens back to one of nature's oldest known chemical innovations – the self-assembly of lipid membranes that surround every living cell.
The research appears in the Nov. 29 issue of the Journal of the American Chemical Society (JACS 2006, 128, 15098).
Researchers believe the new method will allow them to create a wide variety of useful materials, including extra-potent cancer drugs and more efficient catalysts for the chemical industry.
The method makes use of the hydrophobic effect, a biochemical phenomena that all living creatures use to create membranes, ultra-thin barriers of fatty acids that form a strong yet dynamic sack around the cell, sealing it from the outside world. Cell membranes are one example of a micelle, a strong bilayer covering that is made of two sheets of lipid-based amphiphiles, molecules that have a water-loving, or hydrophilic, end, and a water-hating, or hydrophobic, end. Like two pieces of cellophane tape being brought together, the hydrophobic sides of the amphiphilic sheets stick to one another, forming the bilayered micelle.
"When the micelle forms, the process drives the packing of all the junction points, which connect the hydrophobic and the hydrophilic part of an amphiphile, into a high-density array," said Eugene Zubarev, the Norman Hackerman-Welch Young Investigator and assistant professor of chemistry. "By attaching a nanoparticle to the junction point of an amphiphile, we can, in effect, use micellization as a means to assemble billions and billions of individual nanoparticles into well-defined one-dimensional superstructures that are soluble in water."
Zubarev and colleagues synthesized V-shaped amphiphiles of polystyrene-b-poly(ethylene oxide) and attached two-nanometer diameter gold particles at the focal point of the V. Upon adding water and inducing micelle formation, the team found it could create tightly packed cylinders of gold nanoparticles measuring just 18 nanometers in diameter.
All micelles form in three allowable shapes – spheres, cylinders and sack-like vesicles. By varying the length of the polystyrene arm, the solvents used and the size of the gold particles, Zubarev and colleagues were able to form spheres, vesicles and vary the diameter of their cylinders, some of which grew to well-over 1,000 nanometers in length.
"We believe further manipulation of these parameters may provide an opportunity to control the optical and catalytic properties of these nanoassemblies," Zubarev said.
Jade Boyd | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy