Measuring the Temperature of Nanoparticles
One of the holy grails of nanotechnology in medicine is to control individual structures and processes inside a cell. Nanoparticles are well suited for this purpose because of their small size; they can also be engineered for specific intracellular tasks.
When nanoparticles are excited by radio-frequency (RF) electromagnetic fields, interesting effects may occur. For example, the cell nucleus could get damaged inducing cell death; DNA might melt; or protein aggregates might get dispersed.
Some of these effects may be due to the localized heating produced by each tiny nanoparticle. Yet, such local heating, which could mean a difference of a few degrees Celsius across a few molecules, cannot be explained easily by heat-transfer theories. However, the existence of local heating cannot be dismissed either, because it's difficult to measure the temperature near these tiny heat sources.
Scientists at Rensselaer Polytechnic Institute have developed a new technique for probing the temperature rise in the vicinity of RF-actuated nanoparticles using fluorescent quantum dots as temperature sensors. The results are published in the Journal of Applied Physics.
Amit Gupta and colleagues found that when the nanoparticles were excited by an RF field the measured temperature rise was the same regardless of whether the sensors were simply mixed with the nanoparticles or covalently bonded to them. "This proximity measurement is important because it shows us the limitations of RF heating, at least for the frequencies investigated in this study," says project leader Diana Borca-Tasciuc. "The ability to measure the local temperature advances our understanding of these nanoparticle-mediated processes."
The article, "Local Temperature Measurement in the Vicinity of Electromagnetically Heated Magnetite and Gold Nanoparticles" by Amit Gupta, Ravi Kane and Diana-Andra Borca-Tasciuc appears in the Journal of Applied Physics. See: http://link.aip.org/link/japiau/v108/i6/p064901/s1
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ABOUT JOURNAL OF APPLIED PHYSICS
Journal of Applied Physics is the American Institute of Physics' (AIP) archival journal for significant new results in applied physics; content is published online daily, collected into two online and printed issues per month (24 issues per year). The journal publishes articles that emphasize understanding of the physics underlying modern technology, but distinguished from technology on the one side and pure physics on the other. See: http://jap.aip.org/
The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world's largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.
Jason Socrates Bardi | Newswise Science News
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