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 Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>