Nanoparticle and health

2008/08/15 - Nanotechnology shows longer particles better to enter cancer cells

Nanotech methods offer a variety of ways to alter the properties of nanostructures to optimize drug delivery. A process that allows the fabrication of different shapes of particles varying in size from about 100 nm to several micrometers demonstrates that long particles are internalized by cancer cells more efficiently than are round particles. From the University of North Carolina at Chapel Hill (credit PhysOrg.com) “UNC study: shape, not just size, impacts effectiveness of emerging nano-medicine therapies“:

In the budding field of nanotechnology, scientists already know that size does matter.

But now, researchers at the University of North Carolina at Chapel Hill have shown that shape matters even more — a finding that could lead to new and more effective methods for treating cancer and other diseases, from diabetes and multiple sclerosis to arthritis and obesity.

A team of researchers led by Joseph DeSimone, Ph.D., Chancellor’s Eminent Professor of Chemistry in UNC’s College of Arts and Sciences and William R. Kenan, Jr. Distinguished Professor of Chemical Engineering at North Carolina State University, and Stephanie Gratton, a graduate student in DeSimone’s lab, have demonstrated that nanoparticles designed with a specific shape, size and surface chemistry are taken up into cells and behave differently within cells depending on these attributes.

Their findings appear in this week’s online early edition of the journal PNAS, the Proceedings of the National Academy of Sciences [abstract].

…Using PRINT® (Particle Replication in Non-wetting Templates) technology — a technique invented in DeSimone’s lab that allows scientists to design and produce “custom-made” nanoparticles — the UNC researchers made particles with specific shapes, sizes and surface charges. DeSimone said the aim is to optimize particle attributes for specific therapeutic objectives.

“This would mean that we could deliver lower dosages of drugs to specific cells and tissues in the body and actually be more effective in treating the cancer,” said DeSimone, who is also a member of UNC’s Lineberger Comprehensive Cancer Center and the co-principal investigator for the Carolina Center for Cancer Nanotechnology Excellence.

…the scientists discovered that long, rod-shaped particles (diameter, 150 nanometers; height, 450 nanometers) were internalized by cells approximately four times faster than lower aspect ratio particles (diameter, 200 nanometers; height, 200 nanometers), and traveled significantly further into the cells as well.

More information about the PRINT® process can be found on the web site of the DeSimone research group.
—Jim

2008/07/24 - Exhibition Envisages Future of Nanoparticles

New-media art installations that caution visitors about a future when books are relics of the past, and nanoparticles represent a pervasive threat to human health, will be on display starting ...
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2008/07/24 - New Centre to Study Possible Health Effects of Human Exposure to Nanoparticles

The Health Protection Agency has set up a new centre to study the possible health effects of human exposure to nanoparticles. The National Nanotoxicology Research Centre (NNRC) is being de...
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2008/07/15 - SurModics Licensed Lipid Nanoparticle Technology from PharmaSol

SurModics, Inc., a leading provider of surface modification and drug delivery technologies to the healthcare industry, announced today that its Brookwood Pharmaceuticals subsidiary has lic...
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2008/07/01 - Professor Awarded Grant to Conduct Nanoparticle Cancer Research

A biomedical engineering assistant professor at The University of Texas at Austin has been awarded a $1.5 million National Institutes of Health/National Cancer Institute grant to conduct nanop...
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2008/05/12 - Nanotechnology to kill bacteria OK in hospitals but suspect in commercial products

There is hope that nanotechnology in the form of silver nanoparticles will provide protection against drug-resistant bacteria in hospitals, but there is also concern that unregulated use of silver nanoparticles in commercial products will damage the environment. A mention on KurzweilAI.net led to this article by Monica Heger on SciAm.com News, provided originally by Scienceline. From “A Silver Coating in the Fight Against Microbes“:

A new technique in paint making could soon make almost any surface germ-free. Researchers have made paint that is embedded with silver nanoparticles, known for their ability to kill bacteria and other microbes, in the hopes that hospitals will coat their walls and countertops to fight infection.

According to the U.S. Centers for Disease Control and Prevention, more than 1 million people per year contract bacterial infections in hospitals. Silver itself is an excellent bacteria fighter, and in nanoparticle form it is even more potent at killing microorganisms. So far it has not shown any adverse effects in humans.

However, some scientists are concerned that silver nanoparticles may not be as harmless as they appear. Little research has been done on their health and environmental effects, and silver kills good microorganisms along with the bad. Also, there are currently no restrictions on using silver nanoparticles, which are already popping up in a range of consumer products that tout their antibacterial properties.

“Nanoparticles are very small and they are interacting with the bacteria and rupturing the cell wall,” says chemist George John of City College of New York and lead author of the study, published in the journal Nature Materials [abstract] last month. This rupturing kills the bacteria, he explains.

A silver nanoparticle is a small cluster of silver atoms less than 100 nanometers, or 100 billionths of a meter, wide. Because of their size, nanoparticles exhibit different properties than their bulkier counterparts. They have a high surface area to volume ratio, which makes them able to dissolve in paint. Nanoparticles are also being studied for their use in medicine, particularly in drug delivery, since they are able to pass easily through cell membranes.

…”It is more or less like a soaping or detergent effect,” says Lucian Lucia, associate professor of chemistry at North Carolina State University. The nanoparticle destroys the cell wall of the microbe.

Lucia and John both agree that bacteria cannot build up a resistance to silver nanoparticles as they can to antibiotics, because of the way the silver nanoparticle attacks — destroying the structure of the cells and killing them. Antibiotics, on the other hand, suppress the activity of bacteria but don’t necessarily kill them. “That’s the beauty of silver,” Lucia says. “There’s no way to develop a resistance to it.”

…Andrew Maynard, the chief science advisor for the Project on Emerging Nanotechnologies, funded by the Woodrow Wilson International Center for Scholars and the Pew Charitable Trust, is … concerned about the lack of research and regulation on the use of silver nanoparticles. He says this technology is cropping up in unlikely products, like socks, kitchenware and cosmetics, to name a few.

“You have an anti-microbial agent appearing everywhere, including children’s fluffy toys, with no knowledge about its health or environmental implications,” Maynard says. “What are the chances of it taking out an ecologically important bacteria?”

And it is this question that Maynard wants answered before the technology is applied to any more commercial products. On the other hand though, Maynard acknowledges that the use of silver nanoparticles holds promise, particularly in hospital settings.

—Jim