Navigation Links
When nano may not be nano
Date:9/13/2009

DURHAM, N.C. The same properties of nanoparticles that make them so appealing to manufacturers may also have negative effects on the environment and human health.

However, little is known which particles may be harmful. Part of the problem is determining exactly what a nanoparticle is.

A new analysis by an international team of researchers from the Center for the Environmental Implications of NanoTechnology (CEINT), based at Duke University, argues for a new look at the way nanoparticles are selected when studying the potential impacts on human health and the environment. They have found that while many small particles are considered to be "nano," these materials often do not meet full definition of having special properties that make them different from conventional materials.

Under the prevailing definition, a particle is deemed nano if its diameter is between 1 and 100 nanometers (nm) about 1/10,000 the diameter of a human hair and if it has properties that significantly differ from its naturally occurring, or bulk, counterpart.

The special properties of nanoparticles come from their high surface-area-to-volume ratio. They also have a considerably higher percentage of atoms on their surface compared to bulk particles, which can make them more reactive. These man-made materials can be found in a vast array of consumer products, including paints and sunscreens, as well as in water treatment plants and drug delivery systems.

For most of this decade, discussions of nanoparticles have tended to focus more on their size than their properties. However, after reviewing the scientific literature, the Duke-led team believes that the old definition is not specific enough. A definition that focuses on properties is critical, they say, to help scientists determine which particular nanoparticles are the most likely to represent a threat to the environment or human health.

Generally speaking, it is the very smallest particles (less than 30 nanometers) that should receive the most attention in studying the environmental and human health impacts of nanomaterials, according to Mark Wiesner, a Duke professor of civil and environmental engineering and director of the federally funded CEINT.

"There are an infinite number of potential new man-made nanoparticles, so we need to find a way to narrow our efforts to those that have the greatest likelihood of having the unique properties with unique effects," Wiesner said.

"A key question to be answered is whether or not a particular nanoparticle has toxic or hazardous properties that are truly different from identical particles in their bulk form," Wiesner continued. "This question has not been answered. To do so, we need to be speaking the same language when assessing any unique properties of these novel materials."

The results of Wiesner's analysis were published online in the journal Nature Nanotechnology. The study was supported by CEINT, which is jointly funded by the National Science Foundation and Environmental Protection Agency.

Specifically, the researchers found that nanoparticles approaching the 100 nm end of the size spectrum tend to have fewer special properties when compared to their bulk counterparts. Furthermore, they found that nanoparticles smaller than 30 nm tend to exhibit the unique properties that should command increased scrutiny, Wiesner said.

"Many nanoparticles smaller than 30 nanometers undergo drastic changes in their crystalline structure that enhance how the atoms on their surface interact with the environment," Wiesner said.

For example, because of the increased surface-area-to-volume ratio, nanoparticles can be highly reactive with other chemicals in the environment and can also disrupt certain activities within cells.

"While there have been reports of nanoparticle toxicity increasing as the size decreases, it is still uncertain whether this increase in reactivity is harmful to the environment or human safety," Wiesner said. "To settle this issue, toxicological studies should contrast particles that exhibit novel size-dependant properties, particularly concerning their surface reactivity, and those particles that do not exhibit these properties."


'/>"/>

Contact: Richard Merritt
richard.merritt@duke.edu
919-660-8414
Duke University
Source:Eurekalert  

Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
When nano may not be nano
(Date:2/8/2017)... YORK , Feb. 7, 2017 Report Highlights ... The ... should reach $11.4 billion by 2021, growing at a compound ... Includes - An overview of the global markets for synthetic ... 2015, estimates for 2016, and projections of compound annual growth ...
(Date:2/7/2017)... Feb. 7, 2017   MedNet Solutions , an ... spectrum of clinical research, is pleased to announce that ... its innovative, highly flexible and award winning eClinical solution, ... iMedNet is a proven Software-as-a-Service (SaaS) clinical ... Capture (EDC), but also delivers an entire suite of ...
(Date:2/6/2017)... , Feb. 6, 2017 According to ... are driving border authorities to continue to embrace ... there are 2143 Automated Border Control (ABC) eGates ... deployed at more than 163 ports of entry ... to 2016 achieving a combined CAGR of 37%. ...
Breaking Biology News(10 mins):
(Date:2/27/2017)... 27, 2017 A Europe-wide survey of institutes ... using animals in their research treat them with due care. The ... detailed analysis of the results indicates that there is a strong ... put into practice the principles of the 3Rs (Refine, Reduce, ... What are ...
(Date:2/27/2017)... HAMILTON, Bermuda , Feb. 27, ... ADXS ) and SELLAS Life Sciences ... developing cancer immunotherapies, today announced that Advaxis has ... cancer immunotherapy agent using Advaxis, proprietary Lm ... targeted heteroclitic peptide antigen mixture (galinpepimut-S). ...
(Date:2/26/2017)... ... 26, 2017 , ... Rob Lowe is a well recognized television personality, so ... focuses on issues that are important to the American public and important to society ... been a hot topic around the world for a few years. , The climate ...
(Date:2/24/2017)... Calif. (PRWEB) , ... February 24, 2017 , ... Chef ... and wine scene. Making stops in several cities, she gained a number of ... adventure began in Stellenbosch, a town in South Africa’s Western Cape province. It ...
Breaking Biology Technology: