Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > ‘Instant Acid’ Method Offers New Insight into Nanoparticle Dispersal in the Environment and the Body

Successive test runs at NIST show how clumping of typical nanoparticles in a solution depends on changes in acidity. Time after acidity jump is shown on the horizontal axis, while the vertical axis is a measure of the size of the nanoparticle aggregates. As pH goes down (and acidity up), both rate of aggregation and size of clumps of nanoparticles goes up. Credit: R. Murphy/NIST
Successive test runs at NIST show how clumping of typical nanoparticles in a solution depends on changes in acidity. Time after acidity jump is shown on the horizontal axis, while the vertical axis is a measure of the size of the nanoparticle aggregates. As pH goes down (and acidity up), both rate of aggregation and size of clumps of nanoparticles goes up. Credit: R. Murphy/NIST

Abstract:
Using a chemical trick that allows them to change the acidity of a solution almost instantly, a team at the National Institute of Standards and Technology (NIST) has demonstrated a simple and effective technique for quantifying how the stability of nanoparticle solutions change when the acidity of their environment suddenly changes*. The measurement method and the problem studied are part of a broader effort at NIST to understand the environmental, health and safety implications of nanoparticles.

‘Instant Acid’ Method Offers New Insight into Nanoparticle Dispersal in the Environment and the Body

Washington, DC | Posted on June 10th, 2010

Any change in nanoparticle solubility with local acidity (pH**) ultimately affects how they are distributed in the environment as well as their potential for uptake into organisms. This is crucial when designing nanoparticles for use in medicine, explains NIST chemical engineer Vivek Prabhu. "Cells in the body are very compartmentalized. There are places within the cell that have vastly different pH. For instance, in the sea of the cell, the cytosol, pH is regulated to be about 7.2, which is slightly basic. But within the lysosome, which is where things go to get broken down, the pH is about 4.5, so it's very acidic."

Nanoparticles designed for use in drug therapy or as contrast agents for medical imaging typically are coated with molecules to prevent the particles from clumping together, which would reduce their effectiveness. But the efficacy of the anti-clumping coating often depends on the pH of the environment. According to the NIST team, while it's relatively easy to put nanoparticles in a solution at a particular pH and to study the stability of the suspension over long times, it is difficult to tell what happens when the particles are suddenly exposed to a different level of acidity as often occurs in environmental and application contexts. How long does it take them to react to this change and how?

"Our idea borrows some of the materials used in photolithography to make microcircuits," says Prabhu. "There are molecules that become acids when you shine a light on them—photo acid generators. So instead of manually pouring acid into a solution and stirring it around, you start with a solution in which these molecules already are mixed and dissolved. Once you shine light on it …bam! Photolysis occurs and it becomes acidic." The acidity of the solution can be made to jump a major step—an amount chosen by the experimenter—without needing to wait for mixing or disturbing the solution. "It gives you a way to probe the nanoparticle solution dynamics at much shorter timescales than before," says Prabhu.

Using their "instant acid" technique and light scattering instruments to monitor the aggregation of nanoparticles, the NIST team followed the growth of clusters of chemically stabilized latex nanoparticles for the first few seconds after inducing the pH transition with light. Their results demonstrate that under certain conditions, the stability of the nanoparticles—their tendency to resist clumping—becomes very sensitive to pH. Studies such as these could provide a stronger foundation to design nanoparticles for applications such as targeting tumor cells that have levels of acidity markedly different from normal cells.

The work was supported in part by the National Research Council-NIST Postdoctoral Fellowship Program.

* R.J. Murphy, D. Pristinski, K. Migler, J.F. Douglas and V.M. Prabhu. Dynamic light scattering investigations of nanoparticle aggregation following a light-induced pH jump. Journal of Chemical Physics. 132, 194903 (2010) doi:10.1063/1.3425883.

** pH is the common measure used by chemists of how acidic or basic a solution is. The scale runs from 0 to 14; lower values are more acidic, higher values more basic; 7 is considered neutral.

####

For more information, please click here

Contacts:
Media Contact:
Michael Baum

(301) 975-2763

Copyright © 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

Leti Field Trials Demonstrate New Multicarrier Waveform for Rural, Maritime Broadband Radio: Field Trial in Orkney Islands Used New Filtered Multicarrier Waveform at 700MHz Band with Flexible Bandwidth Usage (Fragmented and Continuous Spectrum) December 18th, 2017

CubeSat Structures Competition Opens Space Design to Students of the World December 16th, 2017

Error-free into the quantum computer age December 15th, 2017

Leti Will Demonstrate First 3D Anti-Crash Solution for Embedding in Drones: Fitted on a Mass-Market Microcontroller, 360Fusion Software Technology Detects any Dynamic Obstacle and Helps Guide Drones Away from Collisions December 15th, 2017

Academic/Education

Luleå University of Technology is using the Deben CT5000TEC stage to perform x-ray microtomography experiments with the ZEISS Xradia 510 Versa to understand deformation and strain inside inhomogeneous materials November 7th, 2017

Park Systems Announces the Grand Opening of the Park NanoScience Center at SUNY Polytechnic Institute November 3rd, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Moving at the Speed of Light: University of Arizona selected for high-impact, industrial demonstration of new integrated photonic cryogenic datalink for focal plane arrays: Program is major milestone for AIM Photonics August 10th, 2017

Announcements

Leti Field Trials Demonstrate New Multicarrier Waveform for Rural, Maritime Broadband Radio: Field Trial in Orkney Islands Used New Filtered Multicarrier Waveform at 700MHz Band with Flexible Bandwidth Usage (Fragmented and Continuous Spectrum) December 18th, 2017

CubeSat Structures Competition Opens Space Design to Students of the World December 16th, 2017

Error-free into the quantum computer age December 15th, 2017

Leti Will Demonstrate First 3D Anti-Crash Solution for Embedding in Drones: Fitted on a Mass-Market Microcontroller, 360Fusion Software Technology Detects any Dynamic Obstacle and Helps Guide Drones Away from Collisions December 15th, 2017

Environment

Silicon Sense first to achieve EPA approval to import detonation nanodiamonds to US: Nanodiamond additives can significantly improve the performance of metal finishing, polymer thermal and mechanical compounds, polymer coatings, CMP polishing and a range of other applications November 29th, 2017

Report highlights opportunities and risks associated with synthetic biology and bioengineering November 22nd, 2017

Dendritic fibrous nanosilica: all-in-one nanomaterial for energy, environment and health November 4th, 2017

Nano-sized gold particles have been shaped to behave as clones in biomedicine November 3rd, 2017

Safety-Nanoparticles/Risk management

How harmful are nano-copper and anti-fungal combinations in the waterways? October 27th, 2017

Do titanium dioxide particles from orthopedic implants disrupt bone repair? September 16th, 2017

Tests show no nanotubes released during utilisation of nanoaugmented materials June 9th, 2017

NanoMONITOR shares its latest developments concerning the NanoMONITOR Software and the Monitoring stations April 21st, 2017

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project