Maltese Cross: What Does It Have to Do With the Skin Barrier?
The skin barrier is made up of lipids (fats) that surround skin cells. There are three types of these lipids: ceramides, fatty acids, and cholesterol. These lipids are found in a 1:1:1 ratio in a healthy skin barrier and come together like puzzle pieces to form a water-tight barrier around skin cells called keratinocytes.
These lipids have hydrophobic (water-repelling) tails and hydrophilic (water-loving) heads. Their hydrophobic tails line up in the middle, forming a bilayer membrane that repels water.
These rows of lipids form lamellar (disk-like) structures composed of bilayer membranes.
Several layers of these membranes are found in between each skin cell in the upper layer of the epidermis, known as the stratum corneum.
When viewed with a cross polarizing microscope, the alignment of these lipids form a maltese cross pattern.
The Maltese cross image is a distinct arrangement that appears when a lamellar membrane is present. It is seen using cross-polarized microscopy. The maltese cross occurs because hydrophobic interactions between the alkyl chains result in macroscopic molecular crystallization. This is visible under a cross-polarized microscope.
The maltese cross pattern is used to determine if a moisturizer uses the proper ratio and type of lipids (ceramides, fatty acids, and cholesterol) to repair the skin barrier. Visualization of the maltese cross pattern in a moisturizer formulation means that the lipids in the moisturizer are mimicking the skin’s natural lamellar membrane structure.
The Best Moisturizers for Dry Skin Display the Maltese Cross Pattern
Looking under a cross-polarized microscope for the Maltese Cross pattern is one way to evaluate the efficacy of barrier repair moisturizers. When the Maltese cross pattern is seen, this means the lipids in the formulation mimic the skin’s natural skin barrier structure. The best moisturizers to repair the skin barrier will display this structure.
Which Moisturizers Display the Maltese Cross Pattern?
Multilamellar emulsion technology (also called MLE technology) is an example of a formulation that shows as a maltese cross under the microscope. This is an image of MLE technology as viewed with a cross-polarized microscope. This is the only technology that has published their maltese cross data as of May 2020. The publication is:
Park, B. D., Youm, J. K., Jeong, S. K., Choi, E. H., Ahn, S. K., & Lee, S. H. (2003). The characterization of molecular organization of multilamellar emulsions containing pseudoceramide and type III synthetic ceramide. Journal of investigative dermatology, 121(4), 794-801.
This image from the Park et al publication demonstrates optical anisotropy by MLE technology in the form of a maltese cross:
How To Find the Best Barrier Repair Moisturizer?
The skin barrier plays an important function helping the skin hold onto water. While there are many “barrier repair moisturizers” on the market, most of them do not mimic the skin’s natural multilamellar structure and therefore do not provide maximal barrier repair. Using the cross-polarizing microscope to evaluate the structure of the moisturizer and look for the maltese cross pattern is a helpful way to assess the efficacy of a barrier repair moisturizer. Ask companies for proof that their moisturizer can do this if you are uncertain of the moisturizer’s true ability to recreate the skin’s natural skin barrier.
Which Moisturizers Produce the Maltese Cross Pattern?
The entire line of Zerafite skincare products use MLE technology that shows as the maltese cross pattern under a cross-polarizing microscope. Zerafite Barrier Repair Moisturizer is an effective option for all eight dry Baumann Skin Types, especially those struggling with eczema – a common inflammatory skin condition caused by an impaired skin barrier. The other brands that contain MLE technology are AtoPalm and Real Barrier. The ingredient on the label to look for is myristoyl/palmitoyl oxostearamide/arachamide mea. Learn more about Zerafite here.
To restore healthy hydration to dry skin, choose a barrier repair moisturizer that shows a Maltese cross pattern under the microscope. This is the only way to eb certain it has the 1:1:1 ratio of ceramides, fatty acids and cholesterol that mimic the skin;s natural barrier.
You can learn more about dehydration and the other three barriers to skin health in this blog.
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