Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > When Particles Are So Small That They Seep Right Through Skin

Quantum dot nanoparticles are visible as fluorescing green dots in the skin.
Quantum dot nanoparticles are visible as fluorescing green dots in the skin.

Abstract:
Scientists are finding that particles that are barely there - tiny objects known as nanoparticles that have found a home in electronics, food containers, sunscreens, and a variety of applications - can breech our most personal protective barrier: The skin.

When Particles Are So Small That They Seep Right Through Skin

ROCHESTER, NY | Posted on September 30th, 2008

The particles under scrutiny by Lisa DeLouise, Ph.D., are almost unfathomably tiny. The particles are less than one five-thousandth the width of a human hair. If the width of that strand of hair were equivalent to the length of a football field, a typical nanoparticle wouldn't even belly up to the one-inch line.

In the September issue of the journal Nano Letters, a team led by DeLouise at the University of Rochester Medical Center published a paper showing that nanoparticles pass through the skin of a living organism, a type of mouse commonly used as a model to study the damaging effects of sunlight.

It's the strongest evidence yet indicating that some nanoparticles are so small that they can actually seep through skin, especially when the skin has been damaged.

The health implications of nanoparticles in the body are uncertain, said DeLouise, an assistant professor of Dermatology and Biomedical Engineering and an expert on the properties of nanoparticles. Other scientists have found that the particles can accumulate in the lymph system, the liver, the nervous system, and in other areas of the body. In her study, she found that the particles accumulate around the hair follicles and in tiny skin folds.

DeLouise, a chemist, points out that her study did not directly address the safety of nanoparticles in any way. "We simply wanted to see if nanoparticles could pass through the skin, and we found that they can under certain conditions," she said.

DeLouise's work is part of a broad field known as nanomedicine that is a strategic area at the University of Rochester Medical Center. The area includes research, like hers, looking at the properties of nanoparticles, as well as possibilities like new forms of drug delivery and nano-sensors that can immediately identify microbes and other threats to our health.

While nanoparticles are becoming widely used in the manufacture of consumer products, they are also under a great deal of study in research labs, and there are some processes - including ordinary candle flames - that produce them naturally. Some of the particles are so small, less than 10 nanometers wide (a nanometer is one-millionth of a millimeter), that they are nearly as small as the natural gaps between some skin cells.

In its paper in Nano Letters, the team studied the penetration of nanoparticles known as quantum dots that fluoresce under some conditions, making them easier to see and track compared to other nanoparticles. The scientists looked at the distribution of quantum dots in mice whose skin had been exposed to about the same amount of ultraviolet light as might cause a slight sunburn on a person. The team showed that while the nanoparticles were able to breech the skin of all the mice, the particles passed more quickly through skin that had been damaged by ultraviolet light.

Part of the explanation likely lies with the complex reaction of skin when it's assaulted by the Sun's rays. In response to ultraviolet light, cells proliferate, and molecules in the skin known as tight-junction proteins loosen so that new cells can migrate to where they're needed. Those proteins normally act as gatekeepers that determine which molecules to allow through the skin and into the body, and which molecules to block. When the proteins loosen up, they become less selective than usual, possibly giving nanoparticles an opportunity to pass through the barrier.

In the future, DeLouise plans to study titanium dioxide and zinc oxide, two materials that are widely used in sunscreens and other cosmetic products to help block the damaging effects of ultraviolet light. In recent years the size of the metal oxide particles used in many consumer products has become smaller and smaller, so that many now are nanoparticles. The effects of the smaller particle size are visible to anyone who takes a walk on the beach or stops by the cosmetics counter at a department store: The materials are often completely transparent when applied to skin. A transparent lip gloss that protects against UV light, for example, or a see-through sunscreen may contain nanoparticles, DeLouise says.

"A few years ago, a lifeguard at the swimming pool wearing sunscreen might have had his nose completely covered in white. Older sunscreens have larger particles that reflect visible light. But many newer sunscreens contain nanoparticles that are one thousand times smaller, that do not reflect visible light," said DeLouise, who noted that many people apply sunscreens after their skin has been damaged by sunlight.

Initial funding from two sources allowed the team to gather the evidence necessary to expand the project dramatically. DeLouise's project was first funded by the University's Environmental Health Sciences Center, which supported graduate student Luke Mortensen during his research. The University's Clinical and Translational Science Institute has also awarded $100,000 to the team, and DeLouise has just received $394,000 from the National Science Foundation to expand the project for the next three years. She will be working with dermatologist Lisa Beck, M.D., who is an expert in allergic skin disorders.

In addition to DeLouise and Mortensen, authors of the paper include Günter Oberdörster, Ph.D., professor of Environmental Medicine and a widely recognized authority on the bio-effects of nanoparticles. Oberdörster is director of the Particulate Matter Center, funded by the Environmental Protection Agency, where scientists study the link between tiny air particles we breathe every day and our cardiovascular health. Dermatologist Alice Pentland, M.D., professor and chair of the Department of Dermatology and an expert on how sunlight brings about skin cancer, was also an author.

####

For more information, please click here

Contacts:
Tom Rickey
(585) 275-7954

Copyright © University of Rochester Medical Center,

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Surfing a wake of light: Researchers observe and control light wakes for the first time July 6th, 2015

Tel Aviv/Tsinghua University project uses crowd computing to improve water filtration: The research, a product of the new TAU-Tsinghua XIN Center, was conducted by 150,000 volunteers at IBM's World Community Grid July 6th, 2015

Transition from 3 to 2 dimensions increases conduction, MIPT scientists discover July 6th, 2015

A Stretchy Mesh Heater for Sore Muscles July 6th, 2015

Nanomedicine

A Stretchy Mesh Heater for Sore Muscles July 6th, 2015

New Biosensor Produced in Iran to Detect Effective Drugs in Cancer Treatment July 4th, 2015

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

Iranian Scientists Find Simple, Economic Method to Synthesize Antibacterial Nanoparticles July 2nd, 2015

Discoveries

Fundamental observation of spin-controlled electrical conduction in metals: Ultrafast terahertz spectroscopy yields direct insight into the building block of modern magnetic memories July 6th, 2015

Surfing a wake of light: Researchers observe and control light wakes for the first time July 6th, 2015

Transition from 3 to 2 dimensions increases conduction, MIPT scientists discover July 6th, 2015

A Stretchy Mesh Heater for Sore Muscles July 6th, 2015

Announcements

Surfing a wake of light: Researchers observe and control light wakes for the first time July 6th, 2015

Tel Aviv/Tsinghua University project uses crowd computing to improve water filtration: The research, a product of the new TAU-Tsinghua XIN Center, was conducted by 150,000 volunteers at IBM's World Community Grid July 6th, 2015

Transition from 3 to 2 dimensions increases conduction, MIPT scientists discover July 6th, 2015

A Stretchy Mesh Heater for Sore Muscles July 6th, 2015

Safety-Nanoparticles/Risk management

NIST ‘How-To’ Website Documents Procedures for Nano-EHS Research and Testing July 1st, 2015

Proposed TSCA Nanomaterial Rule ‘Premature’, Says Former EPA Toxicologist July 1st, 2015

NNI Publishes Workshop Report and Launches Web Portal on Nanosensors: Both outputs support the Nanotechnology Signature Initiative ‘Nanotechnology for Sensors and Sensors for Nanotechnology: Improving and Protecting Health, Safety, and the Environment’ June 24th, 2015

Environmental Issues to Hamper Growth of Global Nanocomposites Market June 4th, 2015

Quantum Dots/Rods

Producing spin-entangled electrons July 2nd, 2015

Philips Introduces Quantum Dot TV with Color IQ™ Technology from QD Vision: Manufacturer is first to offer quantum dot displays for both TVs and monitors June 30th, 2015

Biomanufacturing of CdS quantum dots: A bacterial method for the low-cost, environmentally-friendly synthesis of aqueous soluble quantum dot nanocrystals June 24th, 2015

Iranian Researchers Model, Design Optical Switches June 13th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project