Carbon Nanotubes and Alzheimer's Disease

According to the Alzheimer's Association, 5.3 million Americans have Alzheimer's disease. There is no cure for this disease. Early detection is one of the best ways to combat the ill effects of Alzheimer's disease because early detection means early treatment, which can afford the best quality of life for a victim of the disease. Carbon nanotubes used in magnetic resonance imaging (MRI) and positron emission tomography (PET) scans are in the forefront of leading research and testing for helping health professionals make the earliest possible diagnosis for those who may have or develop the disease.

Alzheimer's Disease

• Alzheimer's disease is the most common cause of dementia and causes the decrease of intellectual and social abilities severe enough to interfere with a victim's daily life. In Alzheimer's disease healthy brain tissue is slowly destroyed, which causes a steady decrease in the victim's memory and mental capabilities. Alzheimer's disease is not associated with normal aging, but the risk of developing this disease increases as you get older. At present, there is not a cure. There are treatments available, though, that may improve the quality of life of a victim of Alzheimer's disease.

Normal Brain

• A person who does not have Alzheimer's disease has a brain that consists of billions of nerve cells called neurons. Each neuron consists of a cell body, dendrites, and an axon. Axons and dendrites together make up nerve fibers. Nerve messages normally travel from one neuron to another. They are separated from each other by narrow spaces called synapses. Neurotransmitters allow messages to cross a synapse. This highly sophisticated process allows the brain to recognize nerve impulses and respond to them appropriately.

Brain Changes

• In an Alzheimer's victim this process slowly becomes severely damaged so that the brain no longer works properly. In the brain of Alzheimer's disease victims, abnormal proteins develop. They are a sticky protein called beta amyloid plaques and masses of fibrous structures called neurofibrillary tangles. These abnormal proteins interfere with the transmission of nerve impulses and cause the death of nerve cells. These abnormal proteins also cause a decrease in the level of neurotransmitters in the brain.

Detection

• Early detection and diagnosis of Alzheimer's disease is important for early treatment with drugs that may decrease the progression of the disease. An MRI of the brain is a sensitive test that produces clear images without using X-rays. MRI utilizes a large magnet, radio waves, and a computer to produce brain images. An MRI can rule out other causes of dementia, such as tumors or strokes. It also might help to show the physical and functional changes in the brain associated with Alzheimer's disease. Recently, nanotechnology has been added to MRI, and PET scans are being done on some children of parents who have Alzheimer's disease.

Nanotechnology

• Nanotechnology offers important new tools that will have an impact on MRIs and PET scans. It is already allowing clinicians to detect abnormal proteins early in Alzheimer's disease. UCLA scientists use brain-scan technology to help diagnose brain aging, often before symptoms appear. Appearing in the January issue of "Archives of General Psychiatry," their study may offer a more accurate method for tracking brain aging. Researchers in this study are able to pinpoint where these abnormal protein deposits are accumulating with the help of carbon nanotubes to help enhance the imaging. Carbon nanotubes could be used as a detection agent to find beta amyloid plaques consisting of a center of abnormal proteins embedded in a group of dying nerve cells, according to the article "Nanotechnological applications for the treatment of neurodegenerative disorders" in "Progress in Neurobiology," volume 88, issue 4, August 2009, pages 272-285.

Carbon Nanotubes

• Carbon nanotubes are long, thin cylinders of carbon. They were discovered in 1991 by S. Iijima. They are large molecules that have a special size and useful physical properties. What makes them so different is that nanotubes have a very broad range of electronic, thermal, and structural properties that can change. The carbon-carbon bond is very strong, making carbon nanotubes very hardy and resistant to most kinds of deformation. Scientists have long been interested in wrapping proteins around carbon nanotubes, and the process is used for various applications in imaging, biosensing, and cellular delivery, according to a study discussed in the Dec. 13 issue of "Science Daily." Tools of this kind are useful when studying certain diseases. For example, an abnormal zinc balance is a characteristic of brain disorders, such as Alzheimer's disease, according to the article "Applying Nanotechnology to Human Health: Revolution in Biomedical Sciences" in the "Journal of Nanotechnology."