Gold nanotubes can destroy cancer cells

Gold nanotubes can act as internal nanoprobes for high-resolution imaging, drug delivery vehicles and agents for destroying cancer cells, scientists say.
The study details the first successful demonstration of the biomedical use of gold nanotubes in a mouse model of human cancer.
"High recurrence rates of tumours after surgical removal remain a formidable challenge in cancer therapy. Chemo- or radiotherapy is often given following surgery to prevent this, but these treatments cause serious side effects," said study lead author Dr Sunjie Ye, from the University of Leeds.
"Gold nanotubes - that is, gold nanoparticles with tubular structures that resemble tiny drinking straws - have the potential to enhance the efficacy of these conventional treatments by integrating diagnosis and therapy in one single system," said Ye.

By controlling the length, the researchers were able to produce gold nanotubes with the right dimensions to absorb a type of light called 'near infrared'.
"When the gold nanotubes travel through the body, if light of the right frequency is shone on them they absorb the light. This light energy is converted to heat, rather like the warmth generated by the Sun on skin," said the study's corresponding author Professor Steve Evans, also from Leeds.

"Using a pulsed laser beam, we were able to rapidly raise the temperature in the vicinity of the nanotubes so that it was high enough to destroy cancer cells," said Evans.

In cell-based studies, by adjusting the brightness of the laser pulse, the researchers say they were able to control whether the gold nanotubes were in cancer-destruction mode, or ready to image tumours.
In order to see the gold nanotubes in the body, the researchers used a new type of imaging technique called multispectral optoacoustic tomography (MSOT) to detect the gold nanotubes in mice, in which gold nanotubes had been injected intravenously.
It was also shown that gold nanotubes were excreted from the body and therefore are unlikely to cause problems in terms of toxicity, an important consideration when developing nanoparticles for clinical use.

The study was published in the journal Advanced Functional Materials.