Our innovation is a miniaturized, wearable, continuous, and inexpensive digital multi wavelength optical sensor that measures dermal water content/skin hydration.
Measurements of dermal water content and skin moisture are essential for both dermatological and cosmetic purposes, and can be carried out using a variety of non-invasive techniques. Most common are electrical capacitance measurements of skin moisture and assessment of skin barrier function through closed-chamber instruments designed to measure transepidermal water loss. However, both techniques are susceptible to environmental influences, have an indirect relationship with the parameter of interest (and hence provide arbitrary outputs) and can lack sensitivity which as a result, can produce erroneous readings. In addition, such devices usually require several minutes of equilibration time in order to stabilise and are considered specialised equipment and hence can only be operated by trained personnel. Alternative techniques such as Raman and Attenuated Total Reflectance (ATR) spectroscopy have also been employed for the analysis of skin moisture, however, these are often large, expensive, commercially unavailable, and their outputs can be difficult to interpret. In recent years, we have employed Near Infrared (NIR) spectroscopy in comprehensive analysis of skin hydration in the optical window of 750-2500 nm, with results demonstrating a clear capability and accuracy of the technique for estimation of dermal water content. NIR was the preferred choice of method because absorption bands of water, proteins and lipids inside the skin are visible in NIR spectra, and can be used to deduce information pertaining to various aspects of skin health such as hydration, and can differentiate between bound and free types of water inside the skin. In turn, this allows a more precise method of measurement. An added advantage is that NIR instrumentation can easily miniaturised into wearable format for in vivo measurements at various anatomical sites. From the literature and our previous work, it is known that a typical NIR spectrum of skin is dominated by two bands around 1450 nm and 1900 nm, attributed to the combination of OH and HOH vibrations of water, and additional bands around 1200 nm and 970 nm that also relate to dermal water. Our technology was designed to exploit this property and is comprised of a multi-wavelength optical sensor that emits light at the wavelengths of interest. This design eliminates the necessity of using benchtop instruments with broad lamp sources, and the generation of wide range spectra. The general system structure is made up of two separate modules: (1) a four wavelength optical probe that attaches to the skin and provides reflectance non-invasive NIR signals in real time, and (2) a processing module that performs analogue to digital conversion, ON/OFF phase operation and signal analysis. The physical dimensions of the device are small, and hence, can be easily worn or incorporated into existing wearable technology such as a smart watch. In addition to measurement of dermal water content, our research findings have demonstrated the possibility of monitoring changes in skin barrier function using NIR technology. This is because NIR spectra of human skin include absorption bands relating to CH and NH functional groups from lipid and proteins constituents, and with appropriate processing algorithms, measurements of these bands can provide important details regarding skin barrier function. Given this information, we are currently working on further advancing our technology by implementing additional wavelengths that relate to skin lipids and proteins. Together, this will provide a truly innovative tool for holistic, accurate and non-invasive skin analysis. A list of some our publications in this area are below: Qassem, M., & Kyriacou, P. (2019). Review of modern techniques for the assessment of skin hydration. Cosmetics, 6(1). doi:10.3390/cosmetics6010003 Qassem, M., & Kyriacou, P. A. (2015). Reflectance near-infrared measurements for determining changes in skin barrier function and scattering in relation to moisturizer application. Journal of Biomedical Optics, 20(9). doi:10.1117/1.JBO.20.9.095008 Qassem, M., & Kyriacou, P. (2014). Use of reflectance near-infrared spectroscopy to investigate the effects of daily moisturizer application on skin optical response and barrier function. Journal of biomedical optics, 19(8), 087007. doi:10.1117/1.JBO.19.8.087007 Qassem, M., & Kyriacou, P. A. (2014). Investigating skin barrier function utilizing reflectance NIR Spectroscopy. 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014, 3735-3738. doi:10.1109/EMBC.2014.6944435 Qassem, M., & Kyriacou, P. A. (2014). Effectiveness of the DreamSkin® garment on relieving symptoms of eczema/dermatitis using electrical and spectroscopic methods: A case study. 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2014, 3723-3726. doi:10.1109/EMBC.2014.6944432 Qassem, M., & Kyriacou, P. A. (2013). In vivo optical investigation of short term skin water contact and moisturizer application using NIR spectroscopy. Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2392-2395. doi:10.1109/EMBC.2013.6610020 Qassem, M., & Kyriacou, P. A. (2013). In vivo optical investigation of short term skin water contact and moisturizer application using NIR spectroscopy. In Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference Vol. 2013 (pp. 2392-2395). doi:10.1109/EMBC.2013.6610020 Qassem, M., & Kyriacou, P. A. (2013). Comparing the rates of absorption and weight loss during a desorption test using near infrared spectroscopy. Skin Research and Technology, 19(2), 137-144. doi:10.1111/srt.12024 Qassem, M., & Kyriacou, P. A. (2012). In vitro spectrophotometric near infrared measurements of skin absorption and dehydration. Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 6044-6047. doi:10.1109/EMBC.2012.6347372
• Safe (uses light) • Non-invasive • Provides continuous readings in real-time • Inexpensive • Does not require trained operative • Suitable for both professional and consumer markets • Can act as a standalone device or integrated into other wearable technology such as a smart watch
• Consumer – cosmetics and dermatology, body hydration • Clinical dermatology • Cosmetics – product evaluation • Sports and fitness