• 10/8/2005
  • San Francisco, CA
  • staff
  • MedIndia (www.medindia.net)

Gold nanoparticles are potential and very practical agents in therapeutic applications. Researchers from the University of California, San Francisco and Georgia Institute of Technology, writing Cancer Letters (Available online 28 September) demonstrate the efficiency of gold nanospheres as photothermal agent by selectively delivering gold nanoparticles to oral carcinoma cells that overexpress EGFR, a clinically related cancer biomarker, and discuss the potential of using this selective technique in molecularly targeted photothermal therapy.

In the study, two oral squamous carcinoma cell lines and one benign epithelial cell line were incubated with anti-epithelial growth factor receptor (EGFR) antibody conjugated gold nanoparticles and then exposed to continuous visible argon ion laser at 514 nm. It was found that the malignant cells required less than half the laser energy to be killed than the benign cells after incubation with anti-EGFR antibody conjugated Gold nanoparticles. No photothermal destruction was observed for all types of cells in the absence of nanoparticles at four times energy required to kill the malignant cells with anti-EGFR/Au conjugates bonded. Gold nanoparticles thus offer a novel class of selective photothermal agents using a CW laser at low powers.

Photodynamic therapy for the management of malignant tumors is gaining acceptance in Europe and United States for various malignancies as new generation of photosensitizers becomes available and technological improvement in the delivery of light occurs. It is an attractive alternative to surgery or radiation with less morbidity and can preserve the anatomic and functional integrity of many organs such as the tongue or larynx.

The study shows that gold nanoparticles could be bound to malignant cells, making cancer detection easier, and the ability of these particles to absorb light helps kill those cancer cells. In conclusion, Gold nanoparticles are a novel class of photothermal agents causing cell injury and death through conversion of the strongly absorbed light to thermal energy. Gold nanoparticles are easily bio-conjugated and are potentially useful with a range of delivery vectors.