Doug Schoon
Three regions of the nail matrix each produces slightly different types of nail cells to create three distinct regions, as shown in the cross-section. These magnified images help to provide a better understanding of the nail plate. Nail cells are relatively tightly linked together to form row upon row of cells stacked in layers. A typical nail plate is about 100 nail cell layers thick. These individual layers are stacked upon each other and adhere together to create the plate, however the layers are most loosely bound near the center of the plate. Thats why this region of the nail plate looks more fibrous (fiber-like). In this region, these layers can bend quite easily without breaking. The nail plate normally contains about 15% water, much of which is distributed as tiny amounts of moisture concentrated between the layers.
This moisture lubricates the layers of nail cells allowing them to slide and stretch when the nail plate is bent. This explains why the nail plate becomes more flexible when it absorbs water; adding more moisture between the layers allows for additional sliding and greater flexibility without breaking.
This effect reaches a maximum as the nail plate becomes completely saturated when it increases to about a 30% water content. All this extra water between the layers pushes them apart and causes the nail plate to swell and change shape. The plate swells and changes shape each time the hands are soaked in water for more than a minute or two and reverts back to normal shape when the extra moisture is lost. This effect is much more noticeable on thin, weak nail plates. Repeatedly soaking the nail plate in water isnt a good practice. Just a five minute soak in warm water is enough to change the nail plates shape and affect adhesion, especially for nail polish. After a water manicure, the nail plate will revert to its normal shape and thickness; leaving the nail polish coating to crack and/or peel. This is not true for hand washing- it does NOT affect adhesion and should be performed before every service begins.
Natural oils in the nails also help increase flexibility by seeping into the tiny spaces between nail cells. Water and some oils move through the nail plate by diffusion. Diffusion is a scientific law saying that substances flow from areas of high concentration into areas of lower concentration. Diffusion makes a drop of blue dye on a wet piece of paper run or bleed into new areas away from the area of high concentration. Hot liquid wax diffuses up a candle wick to be burned. Diffusion is the reason why we smell fragrances. The fragrance molecules diffuse from the skin where the concentration is high and follows air currents until ending up in the nose.
Oils follow different paths through the nail plate than water does. Oils diffuse mostly between cells, rather than though them; which is one reason why they move more slowly through the plate compared to water. Absorbed oils never come close to the concentration of water, but these oils still provide great benefits to the nail plates. Oils also increase lubrication between the nail cell layers without damaging the nail plate, as water can. A nail plate fully saturated with water will revert back to normal moisture levels overnight, as the water slowly evaporates from the plate. Oils wont evaporate from the nail plate. Also, oils are slower to absorb into the nail plate, much slower than water, making it harder for them to escape from the nail plate. Even hand washing wont remove oils from more than the top 2-3 surface layers of the nail cells. Repeated application of oil slowly increases concentrations within the nail plate over time. Thats one main reason why a high quality, absorbing nail oil is so beneficial to the nail plate. Want another reason? Frequent use of absorbing nail oils can make the nail plate more water resistant and can help slow down water absorption into the plate to prevent excessive moisture build-up. How can you tell if a particular nail oil will absorb into the nail plate? Try rubbing some of the nail oil on the back of your hand. If the nail oil wont penetrate your skin, it wont penetrate the nail plate. Mineral oil and many massage oils are great examples of oils that dont penetrate the nail plate, while jojoba, olive and avocado oils do.
