Nanomedicine

2007 Schools Wikipedia Selection. Related subjects: Health and medicine

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.

The first thorough analysis of possible applications of MNT to medicine can be read in Nanomedicine , 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.

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.

Largemouth bass in water containing fullerenes at 500 parts per billion suffered brain damage in 2004. Half of the lab-grown human skin and liver cells exposed to a solution, containing fullerenes at 20 parts per billion, died. Fullerenes can be made less toxic by attaching hydroxyl groups. The more hydroxyl groups added, the less toxic the fullerenes are. With the best coating, the toxicity level dropped by a factor of 10,000.

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.

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 theraphy for cancer patients. Nanorobots could also be useful in treating vascular disease , physical trauma , and even biological aging .