Featured Research

from universities, journals, and other organizations

Perfectly spherical gold nanodroplets produced with the smallest-ever nanojets

Date:
January 14, 2012
Source:
Katholieke Universiteit Leuven
Summary:
Scientists have developed a new method for optical manipulation of matter at the nanoscale. Using ‘plasmonic hotspots’ – regions with electric current that heat up very locally – gold nanostructures can be melted and made to produce the smallest nanojets ever observed. The tiny gold nanodroplets formed in the nanojets, are perfectly spherical, which makes them interesting for applications in medicine.

Similar to the way water backjets eject droplets of water on the surface of a pond, powerful laser pulses can locally melt gold nanostructures and produce gold nanojets, ejecting perfectly spherical gold nanodroplets.
Credit: Image courtesy of Katholieke Universiteit Leuven

KU Leuven researcher Ventsislav Valev and an international team of scientists have developed a new method for optical manipulation of matter at the nanoscale. Using 'plasmonic hotspots' -- regions with electric current that heat up very locally -- gold nanostructures can be melted and made to produce the smallest nanojets ever observed. The tiny gold nanodroplets formed in the nanojets, are perfectly spherical, which makes them interesting for applications in medicine.

The 'backjet' phenomenon on which the method turns can be compared to a pebble being dropped into water. Tightly focused ultrafast laser pulses carry sufficient energy to locally melt the surface of a gold film. When a laser pulse of light hits the film, a nanoscale backjet -- a nanojet -- of molten gold surges upward.

As the name suggests, nanojets on the surface of a homogeneous gold film are incredibly small, their size being determined by the distribution of energy in the light pulse. This distribution of energy is in turn dependent on the wavelength of light. Initially, scientists anticipated that nanojets could not be significantly smaller than the wavelength of light. In this study however, Ventsislav Valev and his colleagues show that nanojets can in fact be made much smaller with the help of 'plasmonic hotspots'.

Plasmonic hotspots are regions on the surface of metal nanostructures where light causes very strong oscillation of the electrons. Because electron oscillations constitute an electric current and because electric currents heat up the material the same way an electric stove heats up in the kitchen, the plasmonic hotspots are extremely hot. So hot that they can melt the gold in a spot much smaller than the wavelength of light. Dr. Valev and his colleagues were successfully able to demonstrate that this tiny little pool of molten gold can give rise to the smallest nanojets ever observed.

The gold nanodroplets propelled upward by the nanojets solidify in flight, producing perfectly spherical nanoparticles. These gold nanodroplets can be collected and used for medical applications including cancer treatment. The nanoparticles can be attached to molecules and injected in the blood. Once the molecules attach to cancer cells, light can be used to heat up the gold nanodroplets and destroy the cancer cells. Currently, the gold nanoparticles used in medications are chemically synthesised. These chemically synthesised gold nanoparticles have an unavoidably granular aspect. Conversely, gold nanodroplets created by the plasmonic nanojet method detailed by Dr. Valev and his colleagues are perfectly spherical, ensuring a better efficiency.


Story Source:

The above story is based on materials provided by Katholieke Universiteit Leuven. Note: Materials may be edited for content and length.


Journal Reference:

  1. Ventsislav K. Valev, Denitza Denkova, Xuezhi Zheng, Arseniy I. Kuznetsov, Carsten Reinhardt, Boris N. Chichkov, Gichka Tsutsumanova, Edward J. Osley, Veselin Petkov, Ben De Clercq, Alejandro V. Silhanek, Yogesh Jeyaram, Vladimir Volskiy, Paul A. Warburton, Guy A. E. Vandenbosch, Stoyan Russev, Oleg A. Aktsipetrov, Marcel Ameloot, Victor V. Moshchalkov, Thierry Verbiest. Plasmon-Enhanced Sub-Wavelength Laser Ablation: Plasmonic Nanojets. Advanced Materials, 2012; DOI: 10.1002/adma.201103807

Cite This Page:

Katholieke Universiteit Leuven. "Perfectly spherical gold nanodroplets produced with the smallest-ever nanojets." ScienceDaily. ScienceDaily, 14 January 2012. <www.sciencedaily.com/releases/2012/01/120113205444.htm>.
Katholieke Universiteit Leuven. (2012, January 14). Perfectly spherical gold nanodroplets produced with the smallest-ever nanojets. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2012/01/120113205444.htm
Katholieke Universiteit Leuven. "Perfectly spherical gold nanodroplets produced with the smallest-ever nanojets." ScienceDaily. www.sciencedaily.com/releases/2012/01/120113205444.htm (accessed September 20, 2014).

Share This



More Matter & Energy News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins