Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study Shows Quantum Dots Can Penetrate Skin Through Minor Abrasions

07.07.2008
Researchers at North Carolina State University have found that quantum dot nanoparticles can penetrate the skin if there is an abrasion, providing insight into potential workplace concerns for healthcare workers or individuals involved in the manufacturing of quantum dots or doing research on potential biomedical applications of the tiny nanoparticles.

While the study shows that quantum dots of different sizes, shapes and surface coatings do not penetrate rat skin unless there is an abrasion, it shows that even minor cuts or scratches could potentially allow these nanoparticles to penetrate deep into the viable dermal layer – or living part of the skin – and potentially reach the bloodstream.

Dr. Nancy Monteiro-Riviere, professor of investigative dermatology and toxicology at NC State's College of Veterinary Medicine, tested the ability of the quantum dots to penetrate rat skin at 8 and 24 hour intervals. The experiment evaluated rat skin in various stages of distress – including healthy skin, skin that had been stripped using adhesive tape and skin that had been abraded by a rough surface. The researchers also assessed whether flexing the skin affected the quantum dots' ability to penetrate into the dermal layer. Monteiro-Riviere co-authored the study with doctoral student Leshuai Zhang.

While the study indicates that acute – or short-term – dermal exposure to quantum dots does not pose a risk of penetration (unless there is an abrasion), Monteiro-Riviere notes "there is still uncertainty on long-term exposure." Monteiro-Riviere explains that the nanoparticles may be able to penetrate skin if there is prolonged, repeated exposure, but so far no studies have been conducted to date to examine that possibility. Quantum dots are fluorescent nanoparticles that may be used to improve biomedical imaging, drug delivery and diagnostic testing.

This finding is of importance to risk assessment for nanoscale materials because it indicates that skin barrier alterations – such as wounds, scrapes, or dermatitis conditions – could affect nanoparticle penetration and that skin is a potential route of exposure and should not be overlooked.

The study found that the quantum dots did not penetrate even after flexing the skin, and that the nanoparticles only penetrated deep into the dermal layer when the skin was abraded. Although quantum dots are incredibly small, they are significantly larger than the fullerenes – or buckyballs – that Monteiro-Riviere showed in a 2007 study in Nano Letters can deeply and rapidly penetrate healthy skin when there is repetitive flexing of the skin.

Additionally, Monteiro-Riviere's laboratory previously showed quantum dots of different size, shape and surface coatings could penetrate into pig skin. The anatomical complexity of skin and species differences should be taken into consideration when selecting an animal model to study nanoparticle absorption/penetration. Human skin studies are also being conducted, but "it is important to investigate species differences and to determine an appropriate animal model to study nanoparticle penetration," Monteiro-Riviere says. "Not everyone can obtain fresh human skin for research."

Nanoparticles are generally defined as being smaller than 100 nanometers (thousands of times thinner than a human hair), and are expected to have widespread uses in medicine, consumer products and industrial processes.

The study, "Assessment of Quantum Dot Penetration into Intact, Tape-Stripped, Abraded and Flexed Rat Skin," was published in the June issue of Skin Pharmacology and Physiology.

"Assessment of Quantum Dot Penetration into Intact, Tape-Stripped, Abraded and Flexed Rat Skin"

Authors: L.W. Zhang and N.A. Monteiro-Riviere, North Carolina State University

Published: May 2008, in Skin Pharmacology and Physiology.

Abstract: Quantum dot (QD) nanoparticles have received attention due to their fluorescent characteristics and potential use in medical applications. Skin penetration is one of the major routes of exposure for nanoparticles to gain access to a biological system. QD655 and QD565 coated with carboxylic acid were studied for 8 and 24 h in flow-through diffusion cells with flexed, tape-stripped and abraded rat skin to determine if these mechanical actions could perturb the barrier and affect penetration. Nonflexed skin did not show QD penetration 8 or 24 h. Flexed skin showed an increase in QD on the surface of the skin but no penetration at 8 and 24 h. Tape-stripped skin depicted QD only on the surface of the viable epidermis. QD655 penetrated into the viable dermal layers of abraded skin at both 8 and 24 h, while QD565 was present only at 24 h. QD were not detected in the perfusate by fluorescence and inductively coupled plasma-optical emission spectroscopy analysis for cadmium at any time point. These results indicate that the rat skin penetration of QD655 and QD565 is primarily limited to the uppermost stratum corneum layers of intact skin. Barrier perturbation by tape stripping did not cause penetration, but abrasion allowed QD to penetrate deeper into the dermal layers.

Matt Shipman | EurekAlert!
Further information:
http://www.ncsu.edu

More articles from Studies and Analyses:

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

nachricht Pan-European study on “Smart Engineering”
30.03.2017 | IPH - Institut für Integrierte Produktion Hannover gGmbH

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>