Three pronged attack on cancer cells
Researchers including Dr Sunjie Ye and Professor Steve Evans from the School of Physics and Astronomy have shown that gold nanotubes have many applications in fighting cancer including: internal nanoprobes for high-resolution imaging; drug delivery vehicles; and agents for destroying cancer cells
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. 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.
A new technique to control the length of nanotubes underpins the research. 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’, which passes through human tissue. Therefore gold nanotubes travelling through the body will absorb light of the right frequency and convert it to heat, rather like the warmth generated by the Sun on skin. Using a pulsed laser beam, it was possible to rapidly raise the temperature in the vicinity of the nanotubes so that it was high enough to destroy cancer cells.
A new type of imaging technique called ‘multispectral optoacoustic tomography’ (MSOT) was used to detect gold nanotubes which had been intravenously injected in mice. It was also shown that gold nanotubes were excreted from the body and therefore unlikely to cause problems in terms of toxicity, an important consideration when developing nanoparticles for clinical use.
The nanotubes can be tumour-targeted and have a central ‘hollow’ core that can be loaded with a therapeutic payload. This combination of targeting and localised release of a therapeutic agent could, in this age of personalised medicine, be used to identify and treat cancer with minimal toxicity to patients.
The use of gold nanotubes in imaging and other biomedical applications is currently progressing through trial stages towards early clinical studies.
The study details the first successful demonstration of the biomedical use of gold nanotubes, in a mouse model of human cancer. The research paper, ‘Engineering Gold Nanotubes with Controlled Length and Near-Infrared Absorption for Theranostic Applications’, was published in the journal Advanced Functional Materials on 13 February 2015.
The image shows pulsed, near infrared light (shown in red), shining onto a tumour (shown in white) that is encased in blood vessels. The tumour is imaged by multispectral optoacoustic tomography via the ultrasound emission (shown in blue) from the gold nanotubes.
Image credit: Jing Claussen (iThera Medical, Germany)