Friday, July 13, 2012

Nanoscience hits home

Nanoscience became real for me when I learned that sooner or later I will need to replace my hips. Hip replacement in my case will be the cost of too much football, jogging and heavy labor as a youth. When I do switch them out, I will join more than 300,000 Americans that year.

So I now pay close attention to the technologies surrounding artificial hips. My colleague Bob Shepard, for instance, wrote a story the other day about how advances in materials like polyethylene have made hip replacement available to younger patients. UAB Surgeon Herrick Siegel, M.D., in the UAB Division of Orthopaedic Surgery, says the harder, smoother surfaces of the new joints last longer and have coatings that coax bone to grow around them. Together these technologies may soon make fake hips strong enough to last the rest of a 40-something’s life, with less likelihood of a replacement surgery. 

Along the same lines, we wrote a few months ago about how a researcher here is designing a new coating for artificial hips made of nanodiamonds. Yogesh Vohra, Ph.D., director of the UAB Center for Nanoscale Materials and Biointegration, found that nanodiamond coatings promise to further toughen artificial joints and prevent the inflammation caused when metal or composite joints, older technologies, shed debris into the body. The constant grinding force within joints causes even nanodiamond-coated hips to shed some particles. 

Vohra’s early study suggested that the size and concentration of debris shed by diamond-coated hips should cause neither inflammation nor toxicity. With applications emerging daily for nanoparticles in bio-imaging and drug delivery, we need to know if it’s safe for such debris to build up in organs (on purpose in the case of drug delivery).   

In a related example, I saw a story featured in a Discovery Magazine blog 80 beats that described how researchers at MIT and Harvard engineered nanoparticles that shrink to less than a third of their original size when exposed to ultraviolet light. In the darkness, they open back up to their larger size.  The idea is to put them in cancer cells when they are small, turn off the lights, and let them expand to kill the cancer.

Our Veena Antony, M.D., professor in the UAB Division of Pulmonary, Allergy and Critical Care Medicine, said the work reflects the trend in nanoscience toward creating particles that can be turned on when needed, and guided to reach formerly unreachable parts of the body to deliver therapeutic payloads. Some nanoparticles can be activated and moved around the body with a magnet.  Others are heat sensitive, and turn on at a set temperature.  And now, we have UV light control.

Antony and colleagues are using nanoparticles to combat mesothelioma, the cancer that is caused by asbestos exposure.  They hope to use fluorescent particles to both identify a cellular feature only present in cancer cells, and if they succeed, to diagnose and treat this cancer in one sitting.  Specifically, they discovered a biomarker for the cancer (the Ephrin receptor A2) that is not expressed on the normal cells and can target it with fluorescent particles that contain a piece of genetic material, a silencing RNA that kills the cancer cells.

For more information, a good source is the National Science Foundation’s nanoscience page

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