In groundbreaking research, scientists have demonstrated the ability to strategically attach gold nanoparticles - particles on the order of billionths of a meter - to proteins so as to form sheets of protein-gold arrays. The nanoparticles and methods to create nanoparticle-protein complexes can be used to help decipher protein structures, to identify functional parts of proteins, and to "glue" together new protein complexes. Applications envisioned by the researchers include catalysts for converting biomass to energy and precision "vehicles" for targeted drug delivery.
The research, which was conducted at the U.S. Department of Energy's Brookhaven National Laboratory, will be published in the July 2, 2007 issue of the journal Angewandte Chemie.
"Our study demonstrates that nanoparticles are appealing templates for assembling functional biomolecules with extensive potential impact across the fields of energy conversion, structural biology, drug delivery, and medical imaging," said lead author Minghui Hu, a postdoctoral student working with James Hainfeld, Raymond Brinas, Luping Qian, and Elena Lymar in the Biology Department at Brookhaven Lab.
In the field of energy conversion, scientists have been searching for efficient ways to convert organic fuels such as ethanol into electricity using catalytic electrodes. But making single layers of densely packed enzymes, the functional part of such catalytic electrodes, has been a challenge. This new research shows that precisely engineered gold nanoparticles can be used to "glue" enzymes together to form oriented and ordered single layers, and that these monolayers are mechanically stable enough to be transferred onto a solid surface such as an electrode.
For this research, the scientists attached gold nanoparticles to an enzyme complex that helps drug-resistant tuberculosis bacteria survive, which has been studied by Brookhaven Lab biologist Huilin Li. The researchers suggest that gold nanoparticles might also be tailored to inactivate this enzyme complex, thereby thwarting drug-resistant TB - a research avenue they may explore in future studies.
In another part of the study, the researchers used proteins found on the surface of adenovirus, a virus that causes the common cold. Previous studies by Broookhaven's Paul Freimuth have characterized how this virus binds to the human cells it infects, and have suggested that modified forms of adenovirus could be used as vehicles to deliver drugs to specific target cells, such as those that make up tumors.
One key to this approach would be to enhance strong binding to the target cells. Toward that end, Hu and Hainfeld's group attached multiple viral proteins to the gold nanoparticles. Such constructs should have increased binding affinity for target cells and their larger size should extend blood residence time for improved drug delivery.
In another application, this new research showed that gold nanoparticles can enhance scientists' ability to decipher the structures and functionally important regions of protein molecules - the workhorses that carry out every function of living cells and whose dysfunction often leads to disease. With added nanoparticles, the "signal-to-noise ratio" and resolution of an imaging technique known as cryo-electron microscopy were significantly increased. This method might enable analysis of small biological macromolecules and complexes that are currently intractable to analyze by cryo-electron microscopy or x-ray crystallography.
Throughout this work, the biggest challenge was to synthesize size-controllable nanoparticles coated with organic molecules designed to react with specific protein sites. Hu explains the steps: "First, we design the specific interactions between gold nanoparticles and the proteins by coating the gold nanoparticles with functional organic molecules using a biocompatible linker. Then we add a genetically engineered sequence of peptides, called a "tag," to the protein molecule, which acts as the binding site for the gold nanoparticles. Finally, we incubate the nanoparticles with the protein solution to allow the nanoparticles and proteins to bind, transfer the solution onto a transmission electron microscopy grid, and analyze the complexes using state-of-the-art electron microscopes."
This research was funded by Brookhaven's Laboratory Directed Research and Development program, the Office of Environmental and Biological Research within the U.S. Department of Energy's Office of Science, and by the Institute of General Medical Sciences within the National Institutes of Health. Collaborators on the research include: Huilin Li, Guiqing Hu, Yanbiao Zhang, and Paul Freimuth, all from the Biology Department at Brookhaven, and Joseph Wall, Martha Simon, Beth Lin, and Frank Kito of the Brookhaven Lab scanning transmission electron microscope (STEM) team.
Karen McNulty Walsh | EurekAlert!
Show me your leaves - Health check for urban trees
12.12.2017 | Gesellschaft für Ökologie e.V.
Liver Cancer: Lipid Synthesis Promotes Tumor Formation
12.12.2017 | Universität Basel
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
12.12.2017 | Earth Sciences
12.12.2017 | Power and Electrical Engineering
12.12.2017 | Life Sciences