Potential medical applications of such particle transfer has prompted developments in nanomedicine and biology to increase skin permeability. One application of transcutaneous particle delivery could be to locate and treat cancer. Nanomedical researchers seek to target the epidermis and other layers of active cell division where nanoparticles can interact directly with cells that have lost their growth-control mechanisms (cancer cells). Such direct interaction could be used to more accurately diagnose properties of specific tumours or to treat them by delivering drugs with cellular specificity. Nanoparticles
Nanoparticles 40 nm in diameter and smaller have been successful in penetrating the skin. Research confirms that nanoparticles larger than 40 nm do not penetrate the skin past the stratum corneum. Most particles that do penetrate will diffuse through skin cells, but some will travel down hair follicles and reach the dermis layer. The permeability of skin relative to different shapes of nanoparticles has also been studied. Research has shown that spherical particles have a better ability to penetrate the skin compared to oblong (ellipsoidal) particles because spheres are symmetric in all three spatial dimensions. One study compared the two shapes and recorded data that showed spherical particles located deep in the epidermis and dermis whereas ellipsoidal particles were mainly found in the stratum corneum and epidermal layers. Nanorods are used in experiments because of their unique fluorescent properties but have shown mediocre penetration. Nanoparticles of different materials have shown skins permeability limitations.
Diet
Vitamin A, also known as retinoids, benefits the skin by normalizing keratinization, downregulating sebum production which contributes to acne, and reversing and treating photodamage, striae, and cellulite. Vitamin D and analogues are used to downregulate the cutaneous immune system and epithelial proliferation while promoting differentiation. Vitamin C is an antioxidant that regulates collagen synthesis, forms barrier lipids, regenerates vitamin E, and provides photoprotection. Vitamin E is a membrane antioxidant that protects against oxidative damage and also provides protection against harmful UV rays. Several scientific studies confirmed that changes in baseline nutritional status affects skin condition. The Mayo Clinic lists foods they state help the skin: fruits and vegetables, whole-grains, dark leafy greens, nuts, and seeds. See also
Acid mantle
Anthropodermic bibliopegy
Artificial skin
Callus, thick area of skin
List of cutaneous conditions
Cutaneous structure development
Fingerprint, skin on fingertips
Hyperpigmentation, about excess skin colour
Intertriginous
Meissners corpuscle
Pacinian corpuscle
Polyphenol antioxidant
Skin cancer
Skin lesion
Skin repair

References
External links

 Media related to Human skin at Wikimedia Commons
MedlinePlus Skin Conditions National Library of Medicine retrieved 12 November 2013.