Nanoparticles show promise as vehicles for drug delivery, as medical diagnostic tools, and as a cancer treatment agent in their own right. Gold nanoparticles, spheres that vary in size between 5 and 100 billionths of a meter in diameter, are especially useful because of the many ways their metal surfaces can be “functionalized” by attaching tailored molecules to perform different tasks in the body. However, treatments require a large number of particles to be injected into the bloodstream, and these could be hazardous if they interact with the body in unforeseen ways.
According to NIST materials scientist Jack Douglas, one of the principal problems confronting nanomedicine is the tendency of proteins to stick to the nanoparticles that float freely in the bloodstream. “Nanoparticles coated with proteins will generally alter their interaction with the body and the nanoparticles can be expected to induce a complementary change in protein chemical activity,” says Douglas. “The coating also can cause the nanoparticles to clump together in large aggregates, which can provoke a huge immune response. Of course, that’s something you want to avoid.”
Scientists have a poor understanding of these interactions, so the NIST team decided to explore what happens when nanoparticles of different sizes encounter five common blood proteins. With the aid of a bevy of microscopes and spectroscopy devices, the team found several general patterns of behavior. “Once the proteins stick to the nanoparticles, the optical properties of both the particles and the proteins change,” Douglas says. “Measuring these changes helps us quantify the stickiness of the nanoparticle for the proteins, the thickness of the adsorbed protein layer and the propensity of the particles to aggregate due to the presence of the protein layers.”
More specifically, the team learned that all five of the proteins stuck to the gold, causing the NPs to aggregate, and that increasing the spheres’ diameter increased their stickiness. They also found that this aggregation usually caused some change in the shape of the proteins—“which generally implies some change in their function as well,” Douglas says.
Aggregation does not always lead to a toxic response, Douglas says, but can affect whether the drugs on the nanoparticles ever reach their intended target. “The main thing is that interactions are largely set by the existence of the protein layer,” he says. “You want to know something about these protein layers if you want to know what nanoparticles are going to do in the body.”
Douglas says that the NIST study addresses metrology needs identified in a National Research Council report** published this past year calling for more quantitative testing for nanoparticle interactions with biological media and that much more work is needed along this and other lines. “For example, we do not yet understand how different-sized particles bind to the surface membranes of cells, which is where many drug interactions take place,” he says.
* S.H.D. Lacerda, J. Park, C. Meuse, D. Pristinski, M.L. Becker, A. Karim and J.F. Douglas. Interaction of gold nanoparticles with common human blood proteins. ACS Nano, December 18, 2009, DOI: 10.1021/nn9011187.
** NRC report, “Review of Federal Strategy for Nanotechnology-Related Environmental, Health, and Safety Research,” available online at www.nap.edu/catalog.php?record_id=12559#toc.
Chad Boutin | Newswise Science News
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction