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Taming the gold nano droplets

By Vicki Mozo




Tiny gold particles are heated using infrared light from an optical tweezer and the hot gold particle is brought closer and closer towards an artificial cell membrane.
[Image and caption credit: Niels Bohr Institute]



Gold particles are being eyed as a potential treatment to selectively kill cells. How are these particles going to do that?

Gold is a good conductor of heat. Within the body, gold particles can be made to transfer heat to cells, thus create localized heating in a living cell. This is what researchers from Niels Bohr Institute have found when they observed the ability of nano-sized gold droplets in dissolving target cells by melting the lipid membranes.1

The lipid membrane that surrounds a cell plays a very crucial role in keeping the cell functional. The lipid membrane protects the cell from external factors that would otherwise disrupt the normal conditions and activities of the cell. Without a fully functional membrane the living cell would eventually die. This is why pharmaceutical drugs that exist today target the membrane of sick cells (e.g. cancer cells) and disease-causing cells (e.g. bacterial cells).

Similarly, the gold particles work on the lipid membrane of living cells when the research team found that these particles were able to dissolve the membrane of the surrounding cells through heat effects.

The particles have also been found to react strongly to light and emit different colors. The color they emit could indicate the extent of light absorbed and heat conducted. By looking at the color emitted by heated gold droplets the observer can know the level of temperature and therefore be able to regulate temperature.

Anders Krysting, one of the members of Optical Tweezers research group from Niels Bohr Institute, explains that the gold nano droplets can be heated by infrared light using the optical tweezers and by turning the light up and down the heat can be controlled. However, when asked about how they determine the precise temperature of the gold droplets, they can only get a hint based on the effect. Since the gold particles are too small (about 60 to 200 nanometers in size) the temperature would be difficult to measure with utmost accuracy. Hence, the next possible thing is to base it from the effect exerted on the lipid membrane. Based on their calculation, the temperature of the gold particles could be at several hundred degrees at a light intensity of less than 1 watt -- the level at which lipids are expected to melt. 1


What does this tell us?

Gold particles will therefore be a novel medical treatment to manage various pathological conditions. They could be used in treating acne, cells that have turned against one self, and cells that bring disease. This is promising but it appears that more research is needed. Like, if the radiation emitted by the gold particles -- no matter how low -- might incite other biological effects. And if they do, will the effects be desirable, unwarranted, or harmful?

The problem with the treatments we have today is the associated side effects they bring to the patient under treatment. For instance, cancer patients treated by chemotherapy tend to lose their hair because the drug is less sensitive. It exerts its effects to both cancer cells and normal, actively dividing cells. Therefore, an ideal treatment would be one that is highly selective with their target. Are gold nano droplets capable of that? The way I see it -- unlikelyfor now.




1 Niels Bohr Institute, ''Controlled heating of gold nanoparticles'', 2011-01-17, http://www.nbi.ku.dk/english/news/news11/controlled_heating_of_gold_nanoparticles/



To cite (APA-style):

Mozo, V. (2011, May 19). Taming the gold nano droplets. Biology-Online.org.
Retrieved from http://www.biology-online.org


Disclaimer: This article is intended to provide information and individual opinion of the author (and not of the site). Any information contained in this article should not be used to replace professional or medical advice, diagnosis or treatment.

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