08 February 2010

Theranostics: therapy + cancer diagnosis

Gold nanobombs destroyed cancer cellsMembrane
A new experiment with cancer cell cultures opens up an unusual way to fight a dangerous disease.

An international group of researchers from Belarus and the United States has figured out how to selectively explode malignant cells from the inside.

"Targeting a single cell is one of the most important advantages of nanomedicine, and our approach promises that it will be able to achieve an effect localized within a single cell," says Dmitry Lapotko, the project's lead researcher, who now works at Rice University. "The idea is to treat unhealthy cells at an early stage of the disease, until the moment when it begins to progress, and the human condition will deteriorate extremely."

Last year, Dmitry and his colleagues found that gold nanoparticles floating in a biological environment, when irradiated with a bright laser with certain parameters, instantly create incandescent vapor bubbles around themselves, called plasmonic nanobubbles (PNB) by scientists.

With certain settings, PNBs could effectively destroy cells, which was first demonstrated by the example of an attack on an arterial plaque, the experimenters report in a university press release (Rice physicists kill cancer with 'nanobubbles'). A lot of gold nanoparticles flashing under a laser beam worked, by Lapotko's definition, like a jackhammer.

Now the authors of PNB have modified their idea. It has already been proven that gold nanoparticles equipped with specific antibodies can purposefully attach to cancer cells (and even penetrate them), while ignoring healthy ones. Only earlier, gold grains were predicted to play only a role in diagnostics, but Lapotko and his comrades created such "smart" nanoparticles for two purposes at once.

In new experiments on cancer cells, researchers have shown that at the same level of irradiation, gold nanoparticles create flashes bright enough to be videotaped through a microscope (and this is the diagnostic hypostasis of the development), and with an increase in laser power, the same particles destroy the found cells (and this is therapy). The latter technique, by the way, is similar to the ideas of iron and carbon nanobombs.

An explosion initiated by a cluster of gold nanoparticles lasts several nanoseconds.
The colored arrows in the figures show the rays of diagnostic and therapeutic lasers,
differing in power (illustrations by Dmitri Lapotko, Jason Hafner).

Scientists from Belarus and the USA called this dual role of their gold nanoparticles the theranostics process (a combination of therapy and diagnostics). Scientists have tested this method on leukemic cells and cancer cells of the head and neck, finding it effective (details are in the article in Nanotechnology: E Y Lukianova–Hleb et al., Tunable plasmonic nanobubbles for cell theranostic).

Portal "Eternal youth" http://vechnayamolodost.ru08.02.2010

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