German scientists have demonstrated a new laser-based testing methods, which they say could not only be used to determine skin damage from sun exposure, but also to test the efficacy of anti-ageing products.
Developed by researchers from Freidrich Schiller University in Jena and Fruanhofer Institute of Biomedical Technology in St. Ingbert and published in the US journal Optics Letters, the technique focuses on the fabric of the deeper layers of skin, assessing levels of collagen and elastin - skin structures that determine how smooth or wrinkled skin is.
The big difference with the new testing method is that the laser equipment can measures relative amounts of collagen and elastin as a single factor. The scientists say that high readings determine higher collagen content and lower elastin content, with lower readings representing the inverse.
The laser imaging equipment combines the two separate testing apparatus for both the elastin and the collagen through ultra-brief pulses of laser infrared light to stimulate the tissues to emit different coloured light rays - blue for collagen and green for elastin.
Previously these measurements could only be achieved by taking live skin samples from patients - something that made testing both difficult and less accurate.
The researchers say that the laser technique was tested on the forearms of 18 volunteers, which only required tiny swaths of skin fibre to be tested for the elastin/collagen content.
The results found that the amounts of collagen and elastin found in the samples vary among individuals, with it not being uncommon for a healthy 35-year old to have some areas of skin comparable to the average levels found in a 25 year old and other areas of skin comparable to that of a 25 year old.
However, the researchers found that ultimately the proportions of elastin and collagen were more dependent on the sex of the individual.
It has long been known that the molecular make up of women's skin differs from that of male skin, but the scientists say that their work proves that women's skin ages faster than that of male skin because women lose collagen at a higher rate than men as they age.
Although the testing method is expected to have widespread dermatological applications in the medical field, the researchers believe it could also play an important role in determining how effective anti-ageing and sun care products are at maintaining the right sort levels of collagen and elastin necessary to help prevent wrinkling.
"Some cosmetics are thought to change the content of the collagen in the skin," said Johannes Koehler from the Freidrich Schiller University, " but until now, to measure that you had to cut out a piece of skin."