MOLECULAR BIOPHOTONICS VS CANCER

With already a lot of success in the pre-existing methods of cancer treatment and detection like radiotherapy, chemotherapy and surgery, there is a new approach being considered that is far less toxic than the rest. Light, specifically visible light, might start being used to detect and treat cancers in a variety of ways. In many cases in the past, these technologies are limited by the inherently weak optical signals. Regardless of the past, scientific procedures have developed enough to produce new molecules or drugs to be used against cancer.  Optical technologies promise high resolution, non-invasive functional imaging of tissue at competitive costs. Metal nanoshells (particularly gold nanoshells) and titanocene derivatives are the molecules in question, and their potential for the future will be investigated in this article.

Metal nanoshells are a novel type of composite spherical nanoparticle consisting of a dielec- tric core covered by a thin metallic shell which is typically gold. This allows the nanoshell to interact (absorb or scatter or both) with different wavelengths of electromagnetic waves. The exact wavelengths for excitation of the nanoshell which enables the scattering or absorbing optical properties of nanoshells depends on the radius of the core and the thickness of the shell.  They are very biocompatible and can serve either purpose of detection or absorption since the nanoshell design can be altered to provide optimum performance.

For in vivo imaging, gold nanoshells can easily be attached to target cells and since they use a low frequency of waves from the electromagnetic spectrum, they do not have toxic side effects. With an optical technology, however, this is only effective currently in skin, breast cancer and any other cancers that do not exist so deep into the body. Nanoshells can mediate the photothermic destruction of carcinomas due to the fact that scientists can manipulate the size of the nanoparticle’s metallic surface to provide an optimum wavelength for cell destruction (one that borders infrared radiation and visible light on the electromagnetic spectrum to increase energy transfer as heat). The healthy cells are not affected for the most part as only in the presence of the nanoshells will the cells be destroyed, and since they are attached to the receptor sites of cancer cells, it is an effective treatment.

Titanocene derivatives are special compounds that revolve around the metal titanium to treat cancer. These are all photosensitising, meaning that they will respond to light. The research paper that explores the uses of titanocene in cancer therapy suggests how this is a very effective treatment for late stage cancer, such as metastatic breast cancer, since you can still kill cancer cells without harming other healthy cells. Titanocene is activated in the presence of oxygen, which at first, might not seem like a problem. However, regions around tumours are known to be low in oxygen, so even though the light can be directed at the specific region, it is a currently a slow and novel method, but does have a lot of promise in the future.

Titanocene provides more promise and potential in terms of securing good treatment in late stages of cancer, but nanoshells can be doubly used in both detection and treatment. Nanoshells are also more easily manipulated and so can be designed intricately for a specific purpose. Despite this, the fact that titanocene can be used as a carcinoma specific treatment suggests that higher doses can be delivered without killing many healthy cells, increasing chances of survival. Overall, both types of molecules are able to provide a less toxic treatment to cancer, which is what is needed to improve qualities of patients’ lives.

Bhiramah Rammanohar

Photo Credits due to: http://research.tamu.edu/2013/10/29/major-award-to-bolster-texas-am-quantum-laser-technology/