Nanotechnology - a new age weapon against cancer

Cancer disease is one of the most deadly diseases and there are several researches going on to cure it, but above all nanotechnology seems to give the best possible results.

Let’s see some introduction about nanotechnology. What is nanotechnology? Well nano means 10-9 mathematically (1 nanometer = 10-9 meter). Nanotechnology (nanotech) is the study of a material at atomic level. Generally, nanotech deals with size between 1 to 100 nanometer particles; the lower limit is set by the size of atoms, since nanotech must build its devices from atoms and molecules and the upper limit is more or less arbitrary but is around the size that has been mentioned above. Certainly, the phenomena which are different in the atomic structure from the larger structure become apparent and can be made use of in the nano device and involves developing materials or devices possessing within that size, but that is not possible without the help of “quantum mechanics”. Nanotechnology is very diverse, ranging from extensions of conventional device physics to completely new approaches based upon molecular self-assembly, from developing new materials with dimensions on the nanoscale to investigating whether we can directly control matter on the atomic scale. Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in medicine, electronics, biomaterials and energy production.

How small is a nanometer? Well the simplest example can be a nanometer is size of a drop of water compared to the ocean. Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control. Areas of physics such as nanoelectronics, nanomechanics, nanophotonics and nanoionics have evolved during the last few decades to provide a basic scientific foundation of nanotechnology. Currently, many researches are going in the field but the major use can be in curing the mighty cancer, as nanomedicine.

The small size of nanoparticles contains properties which can be very useful in oncology, particularly in imaging. A good example is quantum dots. They are nanoparticles with quantum confinement properties, such as size-tunable light emission, when used in conjunction with MRI (magnetic resonance imaging), can produce exceptional images of tumour sites. These nanoparticles are very advantageous compare to currently used materials. Nanoparticles are much brighter than organic dyes and only need one light source for excitation. This means that the use of fluorescent quantum dots could produce a higher contrast image and at a lower cost than today’s organic dyes used as contrast media. However there is a drawback, the quantum dots are made up of toxic materials so they can be harmful.

Properties of nanoparticle
One of the key properties of a nanoparticle is high surface area to volume ratio. It allows many functional groups to be attached to a nanoparticle, which can seek out and bind to certain tumour cells. The size of nanoparticles allows them to preferentially accumulate at tumour sites because tumours lack an effective lymphatic drainage system. Also, the sensor test chips containing thousands of nanowires, able to detect proteins and other biomarkers left behind by cancer cells, could enable the detection and diagnosis of cancer in the early stages from a few drops of a patient's blood.

The three facts behind the use of nano drug delivery systems are: 1) efficient encapsulation of the drugs, 2) successful delivery of said drugs to the targeted region of the body, and 3) successful release of that drug there. Researchers at Rice University under prof. Jennifer West, have demonstrated the use of 120 nm diameter nanoshells coated with gold to kill cancer tumours in mice. When the tumour cells are irradiated with an infrared laser, which passes through flesh without heating it, the gold is heated sufficiently to cause death to the cancer cells, because the nanoshells are targeted to bond to cancerous cells by conjugating antibodies or peptides to the nanoshell surface.

Nanoparticles of cadmium selenide (quantum dots) glow when exposed to ultraviolet light. When injected, they seep into cancer tumours. The surgeon can see the glowing tumour, and use it as a guide for more accurate tumour removal. In photodynamic therapy, a particle is placed within the body and is illuminated with light from the outside. The particle absorbs this light and gets activated. If the particle is made up of metal, energy from the light will heat the particle and surrounding tissue. The light can also be used to produce high energy oxygen molecules which will chemically react with and destroy the tissues like tumours (chemotherapy). This therapy is appealing for many reasons. It does not leave a “toxic trail” of reactive molecules throughout the body because it is directed where only the light is shined and the particles exist. Photodynamic therapy has potential for a noninvasive procedure for dealing with diseases, growth and tumours.

Recently; UCLA (University of California, Los Angeles) scientists have discovered a way to active the immune system to fight cancer by delivering an immune system-stimulating protein in a nanoscale container called “Vault”, directly into tumours cells (lung cancer cells), harnessing the body's natural defenses to fight disease growth. The vaults, barrel-shaped nanoscale capsules found in the cytoplasm of all mammalian cells, were engineered to slowly release a protein, the chemokine CCL21(CCL21 –  (C-C motif) ligand 21) Homo sapiens), into the tumour. Preclinical studies in mice with particularly lung cancer, showed that the protein stimulated the immune system to recognize and attack the cancer cells, potently inhibiting cancer growth. The new vault delivery system is based on a 10-year, on-going research effort focusing on using a patient's white blood cells to create dendritic cells, cells of the immune system that process antigen material and present it on the surface to other immune system cells. Another, ULCA's Dr. Steven Dubinett used a replication-deficient adenovirus to infect the dendritic cells and prompt them to over-secrete CCL21. The early phase study has shown the dendritic cell method is safe, has no side effects and seems to boost the immune response. The research team found T lymphocytes circulating in the blood stream with specific cytokine signatures, indicating that the lymphocytes were recognizing the cancer as a foreign invader. If successful, the vault delivery method would add as a desperately needed weapon to the arsenal in the fight against lung cancer, which accounts for nearly one-third of all cancer deaths in the United States and kills one million people worldwide every year.

Another new way is found by MIT (Massachusetts Institute of Technology) chemical engineers. According to their research a new type of drug-delivery nanoparticle can be developed that exploits a trait shared by almost all tumours: They are more acidic than healthy tissues. Such particles could target nearly any type of tumour, and can be designed to carry virtually any type of drug, says Paula Hammond, a member of the David H. Koch Institute for Integrative Cancer Research at MIT and senior author of a paper describing the particles in the journal ACS Nano. Like most other drug-delivering nanoparticles, the new MIT particles are cloaked in a polymer layer that protects them from being degraded by the bloodstream. But in acidic environment the outer layer of the nanoparticle degrades, so it exposes the second layer of the particle which helps to penetrate in all kind of tumour cells. This phenomenon is used in treating the tumour cells as their acidic level differs from normal cells by means that  they use more oxygen compare to normal cell because they divide faster than normal cell thus they are more acidic in nature. When the outer layer (made of polyethylene glycol or PEG) breaks down in the tumour's acidic environment, a positively charged middle layer is revealed. That positive charge helps the nanoparticle to enter the tumour cells. Particles with a positive charge can penetrate the negatively charged cell membrane, but such particles can't be injected into the body without a "cloak" of because they would also destroy healthy tissues. The researchers are planning to further develop these particles and test their ability to deliver drugs in animals. But it is expected that it could take 5 to 10 years of development before human clinical trials could begin.

A recent research has concluded that nanoparticles can also be used for improved and enhanced effect of natural T-cells in humans. According to a research in, Darrell Irvine from the MIT and his team discovered that they were able to attach 100 nanoparticle capsules to a T-cell without affecting cell’s function. These capsules are filled with interleukins which increase the ability for the T-cells to push forward and attack the cancerous cells. Interleukins are naturally made in the immune system and work as system regulators by keeping the T-cells fighting by adding the additional interleukins. The team then injected these boosted T-cells into mice who were infected with bone and lung cancer. The T-cells immediately swarmed the cancerous cells and were able to stay functional for much longer than the traditional T-cells. In addition, mice treated with regular T-cells died from tumours within a month, while those treated with the boosted cells were had improving health. Because these T-cells are being modified by the nanoparticles, there is no need for them to be genetically modified which is complex and costly. This process also has the potential to speed up clinical trials.

Well this clearly indicates that nanotech can be used as the supreme weapon against the deadly cancer and finally cancer can be cured permanently. There is no doubt that if nanoparticles give 100% success then cancer will be nothing but just a history.