Quantitative spectroscopy of collagen and water in infrared windows I, III, and IV as an aid to targeted application of skin therapeutics

We are currently investigating a non-invasive technique to determine collagen content and hydration in the skin by the optical methods of absorption, fluorescence and Raman spectroscopy for imaging. A major barrier to the effective use of skin therapies is the difficulty of quantifying existing collagen content and water content. Absorption of near infrared light by skin depends both on the concentration of collagen and the amount of water in the skin. In the near infrared (NIR window I) collagen and water have similar absorption profiles. However, because the infrared spectrum of collagen and water from 900 nm to 1700 nm (window II and III) are significantly different, it allows us to quantify collagen relative to water content. The ratio of the absorption of collagen normalized to water at 1700 nm and at 1950 nm (window III and window IV) is linear in collagen concentration. This can be used to discriminate between tissues by absorption imaging. We compare these results to Raman spectroscopy and native fluorescence. Our goal is to generate data that can be used for qualitative imaging allowing for improvement in assessing the effectiveness of skin-treatment therapies for the health care field to develop a device for home and medical office which can answer the age-old question: “Mirror, Mirror on the wall, where exactly should I apply skin therapeutics for maximum effectiveness and minimal side-effects?”