Unraveling the interactions between cold atmospheric plasma and skin-components with vibrational microspectroscopy.

Using infrared and Raman microspectroscopy, the authors examined the interaction of cold atmospheric plasma with the skin's built-in protective cushion, the outermost skin layer stratum corneum. Following a spectroscopic analysis, the authors could identify four prominent chemical alterations caused by plasma treatment: (1) oxidation of disulfide bonds in keratin leading to a generation of cysteic acid; (2) formation of organic nitrates as well as (3) of new carbonyl groups like ketones, aldehydes and acids; and (4) reduction of double bonds in the lipid matter lanolin, which resembles human sebum. The authors suggest that these generated acidic and NO-containing functional groups are the source of an antibacterial and regenerative environment at the treatment location of the stratum corneum. Based upon the author's results, the authors propose a mechanistic view of how cold atmospheric plasmas could modulate the skin chemistry to produce positive long-term effects on wound healing: briefly, cold atmospheric plasmas have the potential to transform the skin itself into a therapeutic resource.

Similar appearance, different mechanisms: xerosis in HIV, atopic dermatitis and ageing.

Xerosis is one of the most common dermatologic disorders occurring in the elderly and in patients with atopic dermatitis (AD) and human immunodeficiency virus (HIV) infection. Xerosis has been linked to an impaired skin barrier function of the stratum corneum. Using Raman microspectroscopy, we concentrated on deeper skin layers, viable epidermis and dermis of 47 volunteers and associated molecular alterations to the evolution of xerosis and the skin barrier, for example, lipid, water and antioxidant content. A decrease in lipids within the viable epidermis is found for elderly and HIV-patients. Lipid and water values of AD patients and their healthy reference group are similar. Decreases in lipids and simultaneous increases in water are found in the dermis for HIV and AD patients in comparison to their healthy reference groups. Excessive levels of epidermal carotenoids, mainly lycopene, in HIV-patients were found potentially leading to adverse effects such as premature skin ageing.