Nanomedicine

Nanomedicine is the medical application of nanotechnology and related research. It covers areas such as nanoparticle drug delivery and possible future applications of molecular nanotechnology (MNT) and nanovaccinology.

Current problems for nanomedicine involve understanding the issues related to toxicity and environmental impact of nanoscale materials.

Direct funding for nanomedicine projects has begun, and the US National Institute of Health received funding in 2005 to set up four nanomedicine centres. In April 2006, the journal Nature Materials estimated that 130 nanotech-based drugs and delivery systems were being developed worldwide. [1]

The first thorough analysis of possible applications of MNT to medicine can be read in Nanomedicine [2], a book series by Robert Freitas; it analyzes a wide range of possible nanotechnology-based medical devices, and explains the relevant science behind their design.

Contents

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Cancer

Nanoparticles of cadmium selenide (quantum dots) glow when exposed to ultraviolet light. When injected, they seep into cancer tumors. The surgeon can see the glowing tumor, and use it as a guide for more accurate tumor removal.

Jim Heath, a Caltech chemist, is developing nano-sized sensors that can detect and diagnose cancer in the early stages, when there are only a few thousand cancer cells in the body. A few drops of the patient's blood are placed on the sensor test chip. The chip contains tens of thousands of nanowires that can detect proteins and other biomarkers left behind by cancer cells. Cancer is curable in the early stages, so this test could save lives once perfected.

Jennifer West, a bioengineer, used nanoshells coated with gold to kill cancer tumors in mice. The nanoshells are 120 nanometers in diameter, 170 times smaller than a cancer cell. The nanoshells are injected into the mouse. The nanoshells become lodged in the cracks of the tumors. Then the mouse is shot with an infrared laser. The ray passes through the flesh harmlessly, but heats up the gold. The gold burns the cancer cells to death, without harming the healthy cells. No mice have died, even when injected with large doses of nanoshells as per Food and Drug Administration requirement. This Nanomedicine method is more accurate, cheaper, faster, free of side effects, and less dangerous than surgery, chemotherapy, and radiation treatment (4/19/2004).

One scientist, University of Michigan’s James Baker, believes he has discovered a highly efficient and successful way of delivering cancer-treatment drugs that is less harmful to the surrounding body. Baker has developed a nanotechnology that can locate and then eliminate cancerous cells. He looks at a molecule called a dendrimer. This molecule has over a hundred hooks on it that allow it to attach to cells in the body for a variety of purposes. Baker then attaches folic-acid to a few of the hooks (folic-acid, being a vitamin, is recepted by cells in the body). Cancer cells have more vitamin receptors than normal cells, so Baker's vitamin-laden dendrimer will be absorbed by the cancer cell. To the rest of the hooks on the dendrimer, Baker places anti-cancer drugs that will be absorbed with the dendrimer into the cancer cell, thereby delivering the cancer drug to the cancer cell and nowhere else (Bullis 2006).

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Surgery

At Rice University, a flesh welder is used to fuse two pieces of chicken meat into a single piece. The two pieces of chicken are placed together touching. A greenish liquid containing gold-coated nanoshells is dribbled along the seam. An infrared laser is traced along the seam, causing the two side to weld together. This could solve the difficulties and blood leaks caused when the surgeon tries to restitch the arteries he/she has cut during a kidney or heart transplant. The flesh welder could meld the artery into a perfect seal. Nanomedicine has varied applications in Cardiac Surgery also.

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Nanorobots

The somewhat speculative claims about the possibility of using nanorobots in medicine, advocates say, would totally change the world of medicine once it is realised. Nanomedicine would make use of these nanorobots, introduced into the body, to repair or detect damages and infections. A typical blood borne medical nanorobot would be between 0.5-3 micrometres in size, because that is the maximum size possible due to capillary passage requirement. Carbon would be the primary element used to build these nanorobots due to the inherent strength and other characteristics of some forms of carbon (diamond/fullerene composites). Cancer can be treated very effectively, according to nanomedicine advocates. Nanorobots could counter the problem of identifying and isolating cancer cells as they could be introduced into the blood stream. These nanorobots would search out cancer affected cells using certain molecular markers. Medical nanorobots would then destroy these cells, and only these cells. Nanomedicines could be a very helpful and hopeful theraphy for patients, since current treatments like radiation therapy and chemotherapy often end up destroying more healthy cells than cancerous ones. From this point of view, it provides a non-depressed therapy for cancer patients. Nanorobots could also be useful in treating vascular disease[3], physical trauma [4], and even biological aging [5].

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External links

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References

Reviews in the journal Nanomedicine

National Geographic magazine June 2006

Nanotechnology:The future in Medicine 2006 by Rahul Shetty M.D. ISBN 0-9781573-0-3

Bullis, Kevin (Mar/Apr 2006). "Nanomedicine". Technology Review 109 (1): 58-59. Retrieved on 12/10/06.

(4/19/2004) "Nanoshells destroy tumors in mice". Chemical & Engineering News 82 (16): 35. Retrieved on 12/19/06.

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