Iodine in biology damage). In areas where there is little iodine in the diet, typically remote inland areas and semi-arid equatorial climates where no marine foods are eaten, iodine deficiency also gives rise to hypothyroidism, the most serious symptoms of which are epidemic goitre (swelling of the thyroid gland), extreme fatigue, mental slowing, depression, weight gain, and low basal body temperatures. The addition of iodine to table salt (so-called iodized salt) has largely eliminated the most severe consequences of iodine deficiency in wealthier nations, but deficiency remains a serious public health problem in the developing world. Iodine deficiency is also a problem in
Povidone-iodine application, toxicity, and the staining of surrounding tissues. These deficiencies were overcome by the discovery and use of PVP-I, in which the iodine is carried in a complexed form and the concentration of free iodine is very low. The product thus serves as an iodophor. Povidone-iodine has found application in the field of nanomaterials. A wound-healing application has been developed which employs a mat of single wall carbon nanotubes (SWNTs) coated in a monolayer of povidone-iodine. Research has previously found that the polymer polyvinylpyrrolidone (PVP, povidone) can coil around individual carbon nanotubes to make them water-soluble. Povidone-iodine Povidone-iodine (PVP-I), also