Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Improved characterization of nanoparticle clusters for EHS and biosensors research

Clusters of roughly 30-nanometer gold nanoparticles imaged by transmission electron microscopy. (Color added for clarity.)

Credit: Keene, FDA
Clusters of roughly 30-nanometer gold nanoparticles imaged by transmission electron microscopy. (Color added for clarity.)

Credit: Keene, FDA

Abstract:
The tendency of nanoparticles to clump together in solution—"agglomeration"—is of great interest because the size of the clusters plays an important role in the behavior of the materials. Toxicity, the persistence of the nanomaterials in the environment, their efficacy as biosensors and, for that matter, the accuracy of experiments to measure these factors, are all known to be affected by agglomeration and cluster size. Recent work* at the National Institute of Standards and Technology (NIST) offers a way to measure accurately both the distribution of cluster sizes in a sample and the characteristic light absorption for each size. The latter is important for the application of nanoparticles in biosensors.

Improved characterization of nanoparticle clusters for EHS and biosensors research

Gaithersburg, MD | Posted on October 26th, 2011

A good example of the potential application of the work, says NIST biomedical engineer Justin Zook, is in the development of nanoparticle biosensors for ultrasensitive pregnancy tests. Gold nanoparticles can be coated with antibodies to a hormone** produced by an embryo shortly after conception. Multiple gold nanoparticles can bind to each hormone, forming clusters that have a different color from unclustered gold nanoparticles. But only certain size clusters are optimal for this measurement, so knowing how light absorbance changes with cluster size makes it easier to design the biosensors to result in just the right sized clusters.

The NIST team first prepared samples of gold nanoparticles—a nanomaterial widely used in biology—in a standard cell culture solution, using their previously developed technique for creating samples with a controlled distribution of sizes***. The particles are allowed to agglomerate in gradually growing clusters and the clumping process is "turned off" after varying lengths of time by adding a stabilizing agent that prevents further agglomeration.

They then used a technique called analytical ultracentrifugation (AUC) to simultaneously sort the clusters by size and measure their light absorption. The centrifuge causes the nanoparticle clusters to separate by size, the smaller, lighter clusters moving more slowly than the larger ones. While this is happening, the sample containers are repeatedly scanned with light and the amount of light passing through the sample for each color or frequency is recorded. The larger the cluster, the more light is absorbed by lower frequencies. Measuring the absorption by frequency across the sample containers allows the researchers both to watch the gradual separation of cluster sizes and to correlate absorbed frequencies with specific cluster sizes.

Most previous measurements of absorption spectra for solutions of nanoparticles were able only to measure the bulk spectra—the absorption of all the different cluster sizes mixed together. AUC makes it possible to measure the quantity and distribution of each nanoparticle cluster without being confounded by other components in complex biological mixtures, such as proteins. The technique previously had been used only to make these measurements for single nanoparticles in solution. The NIST researchers are the first to show that the procedure also works for nanoparticle clusters.

* J.M. Zook, V. Rastogi, R.I. MacCuspie, A.M. Keene and J. Fagan. Measuring agglomerate size distribution and dependence of localized surface plasmon resonance absorbance on gold nanoparticle agglomerate size using analytical ultracentrifugation. ACS Nano, Articles ASAP (As Soon As Publishable). Publication Date (Web): Sept. 3, 2011 DOI: 10.1021/nn202645b.

** HCG: Human chorionic gonadotropin.

*** See J.M. Zook, R.I. MacCuspie, L.E. Locascio, M.D. Halter and J.T. Elliott. Stable nanoparticle aggregates/agglomerates of different sizes and the effect of their size on hemolytic cytotoxicity. Nanotoxicology, published online Dec. 13, 2010 (DOI: 10.3109/17435390.2010.536615) and the Feb. 2, 2011, NIST Tech Beat article, "NIST Technique Controls Sizes of Nanoparticle Clusters for EHS Studies," at www.nist.gov/public_affairs/tech-beat/tb20110202.cfm#nanoparticles.

####

For more information, please click here

Contacts:
Michael E. Newman

301-975-3025

Copyright © National Institute of Standards and Technology (NIST)

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Searching for errors in the quantum world September 21st, 2018

Viral RNA sensing: Optical detection of picomolar concentrations of RNA using switches in plasmonic chirality September 21st, 2018

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Nanobiotix: Update on Head and Neck Phase I/II Trial with NBTXR3 and Other program data presented at ImmunoRad 2018 September 20th, 2018

Laboratories

Cannibalistic materials feed on themselves to grow new nanostructures September 1st, 2018

A Novel Graphene Quantum Dot Structure Takes the Cake August 24th, 2018

Virginia Tech researchers develop novel process to 3D print one of the strongest materials on Earth August 23rd, 2018

Connecting the (Nano) Dots: NIST Says Big-Picture Thinking Can Advance Nanoparticle Manufacturing August 22nd, 2018

Govt.-Legislation/Regulation/Funding/Policy

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Researchers develop microbubble scrubber to destroy dangerous biofilms September 19th, 2018

Researchers managed to prevent the disappearing of quantum information September 14th, 2018

New photonic chip promises more robust quantum computers September 14th, 2018

Sensors

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Leti Announces EU Project to Develop Powerful, Inexpensive Sensors with Photonic Integrated Circuits: REDFINCH Members Initially Targeting Applications for Gas Detection and Analysis For Refineries & Petrochemical Industry and Protein Analysis for Dairy Industry September 19th, 2018

Rice U. lab probes molecular limit of plasmonics: Optical effect detailed in organic molecules with fewer than 50 atoms September 5th, 2018

Measuring the nanoworld September 4th, 2018

Discoveries

Searching for errors in the quantum world September 21st, 2018

Viral RNA sensing: Optical detection of picomolar concentrations of RNA using switches in plasmonic chirality September 21st, 2018

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

NUS researchers invent new test kit for quick, accurate and low-cost screening of diseases: Test results are denoted by a color change and could be further analyzed by a smartphone app, making it attractive as a point-of-care diagnostic device September 19th, 2018

Announcements

Searching for errors in the quantum world September 21st, 2018

Viral RNA sensing: Optical detection of picomolar concentrations of RNA using switches in plasmonic chirality September 21st, 2018

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Nanobiotix: Update on Head and Neck Phase I/II Trial with NBTXR3 and Other program data presented at ImmunoRad 2018 September 20th, 2018

Environment

Silver nanoparticles are toxic for aquatic organisms: A research team at the UPV/EHU-University of the Basque Country has analysed how zebrafish are affected in the long term by exposure to silver particles September 19th, 2018

Carbon nanodots do an ultrafine job with in vitro lung tissue: New experiments highlight the role of charge and size when it comes to carbon nanodots that mimic the effect of nanoscale pollution particles on the human lung. September 12th, 2018

A human enzyme can biodegrade graphene August 28th, 2018

Large scale preparation method of high quality SWNT sponges August 24th, 2018

Safety-Nanoparticles/Risk management

Silver nanoparticles are toxic for aquatic organisms: A research team at the UPV/EHU-University of the Basque Country has analysed how zebrafish are affected in the long term by exposure to silver particles September 19th, 2018

Carbon nanodots do an ultrafine job with in vitro lung tissue: New experiments highlight the role of charge and size when it comes to carbon nanodots that mimic the effect of nanoscale pollution particles on the human lung. September 12th, 2018

A human enzyme can biodegrade graphene August 28th, 2018

Nanoscience and the future of healthcare kick off first day of ACS national meeting in Boston: Presidential events highlight safety, diversity and groundbreaking research August 2nd, 2018

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project