Tuesday, August 11, 2009

No to cancer with Nanoparticles

nanoparticles, particularly those of a rare earth metal called cerium. The particles are showing potential for a wide range of applications, from medicine to energy. researchers found that cerium oxide nanoparticles have two additional medical benefits: they behave like an antioxidant, protecting cells from oxidative stress, and they can be fine-tuned to potentially deliver medical treatments directly into cells.
Oxidative Stress = Major Headache
Oxidative stress has been implicated as a cause of arthritis, heart disease, and even aging. It also plays a role in several incurable blinding diseases, such as diabetic retinopathy, age-related macular degeneration, and retinal degeneration.

Oxidative stress occurs when too many reactive oxygen species (ROS) are present. These powerful molecules are generated by exposure to ionizing radiation and by commonplace reduction--oxidation reactions within cells. (Peroxide and free radicals are two examples of ROS.)

Usually, enzymes known as antioxidants protect cells from oxidative stress by disarming ROS and minimizing their toxic effects. But sometimes, the number of ROS overwhelms a biological system, causing damage to proteins, DNA, and other cellular materials.
In a nanocrystalline form, cerium oxide is a powerful antioxidant because its latticework crystal structure has many vacancies that can capture oxygen, and the material has a large surface area. Self showed that nanoceria mimic the activity of superoxide dismutases (SOD), an antioxidant that can stop the deadly chain reactions caused by ROS.
Stopping Eye DamageBecause they are bombarded by light and have a very high rate of oxygen metabolism, cells in the retina encounter relatively high numbers of ROS. Seal and his colleagues hypothesized that ROS may represent an "Achilles' heel" of blinding diseases, which can be specifically targeted using cerium oxide nanoparticles.

To test their hypothesis, the researchers used mice whose eyes have retinal defects similar to those found in patients with age-related macular degeneration. They treated some of the mice with nanoceria and then compared the number of lesions that occurred in their retinas. The researchers' results, published in Nature Nanotechnology, indicate that the nanoceria prevented about 85 percent of the damage to the retina.

Through a newly launched company, McGinnis is pursuing the development of nanoceria medical treatments for several causes of vision loss: the genetic eye disease retinitis pigmentosa (RP), age-related macular degeneration, and diabetic retinopathy.
Transferrin based delivery
As reported in ACS Nano, the researchers found that nanoceria with greater positive surface charge were able to bind better to the ligand protein transferrin. Transferrin is over-produced by cancer cells, which therefore have additional transferrin receptors. The researchers found that the transferrin-coated nanoceria would selectively enter cancer cells, demonstrating the potential of nanoceria in targeted treatments.
cerium oxide may protect healthy cells from the damaging effects of radiation given as cancer treatments, and it shows promise for treating arthritis, wound healing, spinal cord injuries, and neurodegenerative diseases. In collaboration with researchers at Imperial College London, Seal and his colleagues are also incorporating these nanostructures into bio-scaffolds for tissue engineering and stem cell differentiation.

Because of its catalytic nature, cerium oxide nanoparticles and their hybrids may be used efficiently in methanol-ethanol conversion, in the production of hydrogen from sugarcane, for pollution control, and as an electrolyte in fuel cells. Seal is excited about extending his nanoceria research into these energy-related areas.

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