Since the emergence of nanotechnology, researchers, regulators and the public have been concerned at the potential toxicity of nano-sized products, the U.S. government has an admirably large funding program for the technology, especially in it’s medical application. And though their haven’t been any large scale commercial breakthroughs, nanomedicine battles on to refine the application of molecular nanotechnology.
Much hope is placed in the forward looking researchers who are as we write, furthering their research into the delivery of drugs via nanoscale particles, macromolecules, biopharmaceuticals, flesh welding surgery utilizing gold coated nanoshells, or the visionary field of neuro-electronic interfaces. The uses of nanoparticles in medicine is seemingly endless, except of course for that handicap all foreign objects face when entering the human body; our immune system and it’s antibodies, Nanomedicine it would seem is the way of the future. At any moment a breakthrough is likely to hit the journals, ‘Nanoparticle Targeting Kills Cancer’ until that day though nonomedicine is largely restricted to diagnostic practice.
A new study undertaken by the University of Oregan suggests that humans have been in the presence of nanoparticles at least since our species first started processing metals, nanoparticles have been transferred to our skin from bracelets, and dropped into our mouths by forks and spoons, we’ve been living with nano particles for well over 3,000 years. “The generation of nanoparticles from objects that humans have contacted for millennia suggests that humans have been exposed to these nanoparticles throughout time,” said chemist James E. Hutchison, co-author of the paper published in the journal ASC NANO. “Rather than raise concern, I think this suggests that we would have already linked exposure to these materials to health hazards if there were any.”
Now, with the help of high-powered transmission electron microscopes, chemists captured never-before-seen views of miniscule metal nanoparticles naturally being created by silver articles such as wire, jewelry and eating utensils in contact with other surfaces. It turns out, researchers say, nanoparticles have been in contact with humans for a long, long time.
The project involved researchers in the the University of Oregan’s Materials Science Institute and the Safer Nanomaterials and Nanomanufacturing Initiative (SNNI), in collaboration with the University of Oregan technology spinoff Dune Sciences Inc. SNNI is an initiative of the Oregon Nanoscience and Microtechnologies Institute (ONAMI), a state signature research center dedicated to research, job growth and commercialization in the areas of nanoscale science and microtechnologies.
The research focused on understanding the dynamic behavior of silver nanoparticles on surfaces when exposed to a variety of environmental conditions.
Using a new approach developed at UO that allows for the direct observation of microscopic changes in nanoparticles over time, researchers found that silver nanoparticles deposited on the surface of their SMART Grids electron microscope slides began to transform in size, shape and particle populations within a few hours, especially when exposed to humid air, water and light. Similar dynamic behavior and new nanoparticle formation was observed when the study was extended to look at macro-sized silver objects such as wire or jewelry.
“Our findings show that nanoparticle ‘size’ may not be static, especially when particles are on surfaces. For this reason, we believe that environmental health and safety concerns should not be defined — or regulated — based upon size,” said James E. Hutchison, who holds the Lokey-Harrington Chair in Chemistry. “In addition, the generation of nanoparticles from objects that humans have contacted for millennia suggests that humans have been exposed to these nanoparticles throughout time. Rather than raise concern, I think this suggests that we would have already linked exposure to these materials to health hazards if there were any.”
Any potential federal regulatory policies, the research team concluded, should allow for the presence of background levels of nanoparticles and their dynamic behavior in the environment.
Because copper behaved similarly, the researchers theorize that their findings represent a general phenomenon for metals readily oxidized and reduced under certain environmental conditions. “These findings,” they wrote, “challenge conventional thinking about nanoparticle reactivity and imply that the production of new nanoparticles is an intrinsic property of the material that is now strongly size dependent.”
While not addressed directly, Hutchison said, the naturally occurring and spontaneous activity seen in the research suggests that exposure to toxic metal ions, for example, might not be reduced simply by using larger particles in the presence of living tissue or organisms.
Co-authors with Hutchison on the paper were Richard D. Glover, a doctoral student in Hutchison’s laboratory, and John M. Miller, a research associate. Hutchison and Miller were co-founders of Dune Sciences Inc., a Eugene-based company that specializes in products and services geared toward the development and commercialization of nano-enabled products. Miller currently is the company’s chief executive officer; Hutchison is chief science officer.
source: acs nano