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Title: Photoprotection from ultraviolet and visible radiation induced damage to the skin
Author: Lawrence, Karl Perry
ISNI:       0000 0004 6497 9924
Awarding Body: King's College London
Current Institution: King's College London (University of London)
Date of Award: 2017
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Solar radiation has numerous effects on the skin. Some are beneficial, however the majority are negative and contribute to development of skin cancer. Most studies have focused on ultra violet radiation (UVR ~290-400nm), however there is growing evidence to suggest that visible light (400-700nm) also causes skin damage. The main way of preventing solar damage is with the use of sunscreens, however these absorb in the UVR region with poor protection in the UVA/visible boundary waveband. There is growing evidence to suggest that synthetic UVR filters damage fragile marine environments, causing bleaching of corals and hormonal changes in fish. There is also evidence that some filters may damage human health, acting as exogenous oestrogens and inducing oxidative stress. The aim of this thesis was to assess biomarkers of skin damage with a range of in vitro and in vivo endpoints: DNA photodamage, inflammation/ immunoregulation, photoageing, oxidative stress and pigmentation. The focus was on broadband solar simulated UVR and its boundary with visible radiation (385-405nm). It was determined whether current sunscreen formulations provided adequate protection in this region, and if the addition of a new synthetic filter, could improve photoprotection. Furthermore, the ability of naturally occurring marine UVR filters, mycosporine-like amino acids (MAAs) was assessed, with a view to the development of a new generation of biocompatible alternatives to eco-toxic synthetic UVR filters. The results demonstrate that there is substantial damage in the UVR/visible boundary region for all biomarkers tested, and sunscreens using currently available filters do not provide sufficient protection; however the addition of the new filter significantly improved the protection offered. The MAA provided significant protection against all endpoints induced by solar simulated UVR. Furthermore, it demonstrated anti-oxidant capacity when added post UVR exposure. These results demonstrate that further investigation into the effects of visible radiation on the skin is required and the importance of improving sunscreens from an efficacy and environmental standpoint.
Supervisor: Young, Antony Richard ; Long, Paul Frederick Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available