Scientists use laser imaging to assess safety of zinc oxide nanoparticles in sunscreen
Ultra-tiny zinc oxide (ZnO) particles with dimensions less than one-ten-millionth of a meter are among the ingredients list of some commercially available sunscreen products, raising concerns about whether the particles may be absorbed beneath the outer layer of skin. To help answer these safety questions, an international team of scientists from Australia and Switzerland have developed a way to optically test the concentration of ZnO nanoparticles at different skin depths. They found that the nanoparticles did not penetrate beneath the outermost layer of cells when applied to patches of excised skin. The results, which were published this month in the Optical Society's (OSA) open-access journal Biomedical Optics Express, lay the groundwork for future studies in live patients.
The high optical absorption of ZnO nanoparticles in the UVA and UVB range, along with their transparency in the visible spectrum when mixed into lotions, makes them appealing candidates for inclusion in sunscreen cosmetics. However, the particles have been shown to be toxic to certain types of cells within the body, making it important to study the nanoparticles' fate after being applied to the skin. By characterizing the optical properties of ZnO nanoparticles, the Australian and Swiss research team found a way to quantitatively assess how far the nanoparticles might migrate into skin.
The team used a technique called nonlinear optical microscopy, which illuminates the sample with short pulses of laser light and measures a return signal. Initial results show that ZnO nanoparticles from a formulation that had been rubbed into skin patches for 5 minutes, incubated at body temperature for 8 hours, and then washed off, did not penetrate beneath the stratum corneum, or topmost layer of the skin. The new optical characterization should be a useful tool for future non-invasive in vivo studies, the researchers write.
Source: Optical Society of America
- Evidence that nanoparticles in sunscreens could be toxic if accidentally eatenWed, 7 Apr 2010, 12:24:42 EDT
- Evidence that nanoparticles in sunscreens could be toxic if accidentally eatenWed, 23 Jun 2010, 13:33:14 EDT
- Tissues tell the tale: Non-invasive optical technique detects cancer by looking under the skinMon, 24 Sep 2012, 20:32:33 EDT
- When particles are so small that they seep right through skinTue, 30 Sep 2008, 11:22:09 EDT
- Historic first images of rod photoreceptors in the living human eyeWed, 8 Jun 2011, 13:39:47 EDT
- Scientists use laser imaging to assess safety of zinc oxide nanoparticles in sunscreenfrom Science DailyWed, 30 Nov 2011, 21:30:26 EST
- Scientists use laser imaging to assess safety of zinc oxide nanoparticles in sunscreenfrom PhysorgWed, 30 Nov 2011, 13:30:48 EST
Latest Science NewsletterGet the latest and most popular science news articles of the week in your Inbox! It's free!
Learn more about
Check out our next project, Biology.Net
From other science news sites
Popular science news articles
- Even with defects, graphene is strongest material in the world
- Detection of the cosmic gamma ray horizon: Measures all the light in the universe since the Big Bang
- Genetic engineering alters mosquitoes' sense of smell
- Allosaurus fed more like a falcon than a crocodile, new study finds
- 'Popcorn' particle pathways promise better lithium-ion batteries