6. Ferritin and Iron Oxide Interactions
Iron oxides like Fe2O3 and Fe3O4 have historically been criticized for turning rusty, causing eyebrows to adopt a reddish hue. Ferritin, which binds to iron and other metals, is indeed a factor in this change.
What Happens to Iron Oxide Particles in the Skin
When iron oxides serve as colorants in semi-permanent pigments and are introduced into the skin, various biochemical and physicochemical reactions occur. These reactions might lead to changes in pigment color over time. Iron oxides like Fe2O3 (hematite) and Fe3O4 (magnetite) are generally stable. However, under certain conditions, they can undergo oxidation or other chemical reactions that affect the stability of the pigment's color.
Understanding Ferritin
Ferritin acts like a biological magnet, attracting iron ions and catalyzing a chemical reaction that can degrade iron oxide pigments. This leads to a reddish or rusty appearance. The longer the pigment remains in the skin, the more susceptible it becomes to this transformation due to the ongoing activity of ferritin.
Iron Storage and Degradation
Ferritin functions to store iron in a non-toxic form and to deposit it safely. When ferritin aggregates, it transforms into a toxic form of iron called hemosiderin. The ferritin protein structure is complex, consisting of 24 protein subunits that form a hollow nanocage with multiple metal-protein interactions. Inside this ferritin shell, iron ions form crystallites with phosphate and hydroxide ions, resembling ferrihydrite. A single ferritin complex can store around 4500 iron (Fe3+) ions.
Factors Contributing to Oxidation
The skin is not a static environment; it's dynamic and rich in biological molecules, enzymes, and cellular components. Ferritin, a protein that stores iron, can play a key role in the oxidation process. It can interact with iron ions, catalyzing oxidation reactions. Environmental factors like UV light exposure, along with physiological factors such as pH and enzymatic activity, can also influence oxidation.