Health Protection Research Unit for Chemical & Radiation Threats & Hazards

Skin and Barrier Function

The Skin and Barrier Function in Radiation and Chemical Exposures


This research theme looks at the role of the skin as a barrier and the effects of UV radiation and age.

As a major route of entry of compounds into the body, the skin represents a significant barrier to chemicals. The skin also plays a role in the development of allergic sensitisation due to chemical exposures.

Modification of skin function occurs naturally with age but may be significantly altered by environmental exposures such as:

  • UV (UVA and UVB) and IR radiation from sunlight
  • atmospheric pollutants
  • chemicals applied to the skin

All of the above cause accelerated changes. This alteration with ageing is associated with:

  • increased production of damaging reactive oxygen species
  • the induction of matrix degrading enzymes
  • altered tissue collagen and elastin expression, with dermal and epidermal layer changes
  • depigmentation and vascular changes with infiltration of immune cells

It is unclear what metabolic changes occur in the skin in relation to dermal metabolism of chemicals and if the demographic changes in cosmetic use of UV may accelerate such changes (Thomson et al, 2010).

While protection of skin from harmful UV is an advantage, there is some evidence that sunscreens may enhance the penetration of potentially harmful chemicals (Brand et al 2003). Also, in UK populations there is seasonal vitamin-D deficiency which is location dependant and which may be enhanced by sunscreens (Diffey 2013).

Aims of the research theme

This research theme will determine the:

  • effects of UV exposure and sunscreens on metabolic activity in human skin and the penetration of chemicals
  • penetration of chemicals in novel formulations including nanoparticles through skin
  • effects of the changes due to age in penetration of chemicals and the UV response of skin

We also aim to identify biomarkers of exposure and effect which indicate genotoxic damage for correlation with barrier function

This research will provide the evidence to demonstrate the role of the skin as a barrier and the effects of UV radiation and age.

Theme leader: Professor Mark Birch-Machin


Cross section of skin


Recent projects in the Skin and Barrier Function in Radiation and Chemical Exposures.