Gold-Silica Nanoshells: Scorching Cancer Cells with Laser
Posted On May 25, 2012
Who could have imagined that laser can be used to cook up tumor cells? Nanospectra Biosciences is currently under clinical trials to develop a new cancer treatment using gold-silica nanoshells. Gold-silica nanoshells are optically tunable nano-sized particles used in medical applications. Their tunable properties and biocompatibility makes them an effective and non-invasive medical device. A gold-silica nanoshell is composed of an inner core made of silica or “glass”, and an outer shell made with gold. In order to be used effectively, nanoshells need to be designed to absorb light at near-infrared (NIR) wavelengths (750 nm-1400 nm), where energy absorption for biological tissue is at its minimum. This is crucial since when laser therapy is applied to excite the nanoshells, the light will not harm any tissue but will penetrate it innocuously.
Nanoshell therapy happens as follows:
1. Gold-silica nanoshells are injected intravenously through the patient’s circulatory system.
2. The nanoshells will travel throughout the body and because its surface is coated with specific antibodies, it can only detect and attach to tumor cells, not healthy tissue.
3. Once attached and aggregated in the tumor site, a 808 nm wavelength laser beam is shined through the skin, penetrating tissue and reaching the nanoshells.
4. The nanoshells absorb the energy, heat up, and thus photothermally ablates or “cooks up” the tumor.
The technique, called Aurolase, is unique because it is non-invasive, biocompatible (non-toxic), and specifically targeted. The smaller the nanoshell, the deeper it can penetrate tissues and the more surface area is available for light absorption and efficient surface-antibody coating. Currently, laboratory nanoshell fabrication has achieved nanoshell sizes of 150~300 nm with an absorption wavelength peak at about 780 nm, close to the desired laser’s 808 nm NIR region. Ongoing research is aimed at taking this concept into becoming a feasible treatment option. The first video below introduces you on how nanotechnology is being used in medicine and the second one describes the Nanospectra technology.
Nanospectra Biosciences is a company founded by Jennifer West in 2002, who helped develop the medical applications of nanoshells in conjunction with Rice University and MD Anderson Cancer Center. Besides targeting cancerous tumors, the nanoshells can also be used to create images or “weld” wounds together to accelerate healing.