Part 1:

By Chetana Deshpande.

The field of nanotechnology has, over the last decade, been surrounded by enormous amount of hype. Therefore, it is almost a compulsion to have at least minimal knowledge about this exciting field. Nanotechnology is simply the study of manipulating matter at the nanoscale, i.e., 1-100 nanometers (nm). It focuses on understanding, controlling and exploiting the properties of materials or structures in the nanoscale. A nanometer is one billionth of a meter or about the size of ten hydrogen atoms. One of the most important terms in nanotechnology is ‘nanoparticle’. A nanoparticle is a small object, sized between 1 and 100 nm, which behaves as a whole unit in terms of its properties. A unique feature of a nanoparticle is that it possesses different properties when compared to the same particle on a micro scale. This is due to fact that the ratio of surface area to volume increases drastically in the nanoscale. These properties can be exploited to our benefits.
Nanotechnology finds its application in a vast range including fields like organic chemistry, semi-conductor physics, device physics, molecular biology, micro fabrication, cosmetics, clothing, food packing, disinfectant making, and so on. The list of applications is almost never-ending! But the most important application of nanotechnology is that in the field of medicine. The vision of nanotechnology in medicine can come from several cartoons and science fiction movies like ‘Fantastic Voyage’ where tiny submarines travel through blood eradicating pathogens. The reality is more prosaic, nonetheless exciting. Like any other field, nanotechnology comes with some disadvantages. The first being the safety concerns of nanoparticles. Due to the high surface area to volume ratio, nanoparticles are very reactive or catalytic. They are also small enough to seep through the cell membranes of organisms. This can cause problems like toxicity, respiratory disturbance, etc. The interactions between living cells and nanoparticles are still relatively unknown.
It’s disappointing but a fact that the cases of cancer have drastically increased in the past few years, due to various factors. Cancer is caused by damage of genes which control the growth and division of cells. Cancerous cell need blood supply to grow. A hormone like molecule causes nearby blood vessel to grow towards the cell to supply the oxygen and other nutrients. Cancer can be cured by rectifying the damaging mechanism of the genes or by stopping the blood supply to the cells or by destroying it. Thus, an accurate method of both detection and treatment is required. The conventional methods of detection include observing the physical growth/changes in the organ by X-rays and/or CT Scans and are confirmed by biopsy through cell culture. However the limitation of this method is that it is not very sensitive and the detection is possible only after substantial growth of the cancerous cells. And in most cases, it cannot be treated in an advanced stage. Nanoparticles, as mentioned earlier, can enter the cells and access the DNA which is affected. This can be done in-vitro also. Thus, detection can be done in the incipient stage.

Conventionally, cancer is cured by surgery or radiation therapy. The former causes loss of organ and a chance of reappearance of cancer, while the latter causes a lot of side effects like burning away of healthy tissues (temporary or permanent), etc. Nanotechnology provides nano structures like nano-cantilevers, nanopores, nanotubes, nanoshells and quantum dotes which are prospective structures that would help in detecting and treatment of cancers. A success story in this field is the effective cure of liver cancer using ‘BrachySil’ by a nanotechnology company “pSivida” undertaken in Singapore General Hospital. BrachySil is a tiny structure made up of modified particles of silicon filled with the radioactive isotope of phosphorus 32P. It is injected into the cancer using a fine needle and the radiation is limited to 8mm, hence destroying only cancer cells and not healthy tissues. After 12 weeks of treatment, the cancer reduced by an average of 80% and could eradicate all primitive stage cases. The silicon eventually breaks down and is excreted. The 32P decomposes to stable isotope, after its half-life of 14 days and is used by the body or is excreted. Thus, there is very less scope for side effects. Such an efficient result is not seen in any other treatments of cancer. This method can be used for treating liver and prostate cancer. There is great potential for this treatment to be expanded into all other forms of cancer and tumors.

An image showing a model of BrachySil.

The scope for nanotechnology is very high as there is a lot more to explore in this field. In the subsequent articles, we will try and show you, various other perspectives nanotechnology can have. So, keep visiting us!

Article in British scientific journal, Nature.
Research paper in Forbes magazine.