Terahertz skinometer for improved cancer prevention and treatment

The incidence of skin cancer in the UK and globally is increasing. There are two main types of skin cancer: melanoma and non-melanoma skin cancer. Basal Cell Carcinoma (BCC) is a non-melanoma skin cancer, and is the most common type (> 80%) of all UK skin cancer cases. It is well known that applying sunscreen helps to protect the skin from the sun but many people are unaware of the need for UVA (315-400 nm) as well as UVB (280-315 nm) protection. Although lower in energy than UVB, the amount of UVA reaching the earth's surface is 30 times more than for UVB. Furthermore, UVA penetrates the skin more deeply, contributing to both carcinogenesis and skin aging via oxidative stress pathways. One of the most common UVA filters is avobenzone, as it is industrially cheap and thus affordable to the consumer. However, it is now well-established that avobenzone photodegrades, which is a serious concern.

In this project, a highly interdisciplinary team consisting of investigators at the University of Warwick in the Departments of Physics, Chemistry, Life Sciences and Medicine, as well as industry partners from Lubrizol (major skin-care provider) and TeraView Ltd (major terahertz (THz)-based instrument provider) will join forces to attack the problem of increasing skin cancer 'prevention' and 'treatment' using a multi-pronged approach. We will improve skin cancer prevention by developing a new UVA, nature-inspired, sunscreen offering longer lasting and more photostable protection than existing sunscreens. To achieve this, we will repurpose the photoprotection mechanisms of other living organisms, specifically those of cyanobacteria and microalgae. These organisms protect themselves from radiation by producing mycosporine-like amino acids (MAAs), a family of molecules which are strong UVA absorbers and are ideal candidates for sunscreen agents, owing to their dual action as UVA filter and antioxidant.

We recognise that sunscreens are composed of a UV filter blended with a moisturiser (emollient); this can make up to 80% of the composition of the sunscreen. We also recognise that sunscreens are applied to skin. Therefore, to optimise the sunscreen composition, we will develop a revolutionary characterisation tool, the 'THz skinometer', which is able to measure parameters of skin in vivo that other techniques cannot. In this way, we will determine the best UV filter/emollient blend. We will investigate whether different skin conditions such as eczema and psoriasis will benefit from a different emollient blend. THz radiation is non-ionising, using low power levels such that thermal effects are insignificant and consequently safe for in vivo imaging of humans as well as non-destructive testing of materials. It is very sensitive to intermolecular interactions such as hydrogen bonds, and probes molecular processes (eg vibrations, chemical reactions) that occur on picosecond (millionth millionth of a second) timescales. In this project we will employ THz techniques to evaluate the effectiveness of emollients and sunscreens in vivo with a view to developing a single sunscreen that covers both the UVA and UVB regions of the solar spectrum.

Furthermore, as a powerful additional feature of our invention, we will also use our THz skinometer to improve the surgical removal, or 'treatment', of skin cancers such as BCC, which often spread out beneath the surface of the skin such that their entirety cannot be detected until surgery. The THz skinometer will be designed to accurately characterise skin in vivo such that it will be able to determine the likely extent of any tumour beneath the surface. In this way, we will identify the full extent of the tumour prior to surgery which will improve skin grafting planning as well as reduce the likelihood of missing any tumour and tumour recurrence. Thus by attacking skin cancer through 'prevention' as well as 'treatment', we aim to reduce 'incidence' and 'morbidity' of skin cancer in the UK & globally.

During (and post) tenure of the grant, we anticipate that the proposed research will impact 'knowledge', 'economy', 'society' and 'people':

Knowledge: The radically new THz skinometer developed will be able to quantitatively measure a unique combination of skin properties including the diffusivity of occluded skin - no other existing technologies can do this hitherto; this will therefore be a powerful new tool for clinicians including dermatologists and skin-care researchers for improving diagnosis, monitoring and treatment of skin conditions. Furthermore, the THz skinometer will also be able to determine the extent of a skin cancer (including areas which are subclinical and not visible using existing technologies) prior to surgery thus facilitating surgeons (and associated staff) planning and reducing patient trauma. Finally, the algorithms developed will be of great significance to the academic community; it will open up a new avenue of in vivo skin research which will be relevant to skin product development as well as skin diagnosis and treatment planning.

On the sunscreen side, the project will investigate photoprotection mechanisms of MAAs, their interaction with emollients and the emollient penetration and hydration of skin. This has the potential to inform researchers using 'top-down' methodologies to develop next generation UVA sunscreens that are suitably robust to photodegradation and optimally designed for normal skin as well as other skin types, since more effective sunscreen will lead to better prevention of skin cancer. As well as optimising sunscreen development, we will also be able to give quantitative feedback on capabilities of moisturisers when used to treat skin conditions such as eczema and psoriasis. Such knowledge is once again crucial to researchers working in the field of skin-care.

Economy: Two major companies are project partners in this proposed research. Lubrizol, a major skin-care provider is greatly interested in our approach, (see letter of support) and the team will look to grow these links during the tenure of the grant and beyond, along with existing links with clinical collaborators at University Hospitals Coventry and Warwickshire (UHCW). Likewise, the development of a new powerful THz imaging capability with TeraView, our second industry project partner, who is internationally known as a leading THz instrument provider, may also lead to the development of a new imaging product. Thus the link with these two industry project partners may have major ramifications to Economy.

Society: The development of a new sunscreen with improved optical properties including increased absorption strength, spectral coverage and photostability will mean that lower concentrations of these sunscreens are added to the formulation. This means that the same sun protection factor (SPF) rating can be achieved whilst reducing the complexity of sunscreens and thus the potential for adverse side-effects (improved healthcare) and thus substantial savings to the skin-care industry (economy). Likewise, the development of the THz skinometer will aid skin diagnosis and treatment planning. This may lead to increased throughput and/or cost savings in the NHS, or even reduction in demand for treatment. It could also shift clinical diagnosis from hospitals to primary providers (GPs), with consequently improved efficiencies.

The proposed work will thus generate multiple synergies with the EPSRC's Healthcare Technologies theme and support the Healthcare Technologies Grand Challenges, namely Frontiers of Physical Intervention, Optimising Treatment, Transforming Community Health and Care and Developing Future Therapies.

People: The interdisciplinary training and development of one PDRA and two PhD students will help to create a talent pool to drive key emerging industries for our future. These talented scientists will also contribute to shaping and inspiring future research addressing healthcare challenges.