Lipid Barrier Structure & Integrity
The intercellular lipids in the outermost skin layer, the stratum corneum, play a vital role in skin barrier function. They act to contain the water inside our bodies, stopping us from fatal levels of dehydration, and they prevent harmful chemicals or infectious organisms from crossing through the skin. Understanding the composition and structure of these lipids is important for many applications, including treating skin diseases, improving skin resistance to irritation and infection, and protecting skin lipids from damage from chemicals, UV light and gaseous pollution.
The way intercellular lipids are packed and organized in the stratum corneum is absolutely vital for their function. Using unique spectroscopic techniques, TRI is able to explore these lipid packing arrangements. Changes in lipid packing in diseased skin, or in skin exposed to various insults (chemicals, sunlight) can be analyzed, and the protective or repair effects of various skin treatments can also be assessed.
Example experiment using isolated stratum corneum - By measuring the effects of heat on CH2 FTIR peak positions we are able reveal changes in lipid packing arrangements. Here we can see two phase transitions, the transition from orthorhombic to hexagonal packing at lower temperatures, and the transition from ordered to fluid chains at higher temperatures. Tm marks the mid-point temperature of the second transition. Measurement of these phase transitions reveals the lipid packing arrangements present in the original sample.