- Develop skin models for sunscreen application
- Characterise nature-inspired sunscreens deposited on skin models with laser spectroscopy
- Create a shortlist of potential sunscreen candidates for toxicity studies
Ultraviolet radiation (UVR) can be both beneficial and deleterious to life.1-4 To combat this, nature has evolved UVR-absorbing molecules, termed UV-filters. UV-filters are each biologically engineered to protect their host, while allowing sufficient absorption in different spectral regions of the solar spectrum for key biological processes such as photosynthesis.5-7 Two such classes of UVR absorbers are sinapates and mycosporine-like amino acids (MAAs), which provide photoprotection to, respectively, plants and microorganisms.8,9 Exemplar sinapate/MAAs are shown in Figure 1.
The controversy surrounding whether current artificial UV-filters, found in commercial sunscreen formulations, are beneficial or detrimental to the environment has fuelled research into alternative sources of UV-filters including those from Nature. This urgency has been intensified given the growing concerns of UV-filters on their ecotoxicity, notably coral bleaching.10-14 Consequently, new formulations containing less toxic UV-filters spanning the solar UVA and UVB (UVA = 400-315 nm; UVB = 315-280 nm) are now considered essential by Skin-Care industries. Sinapates and MAAs present a potentially revolutionary new avenue of future UV-filters given their strong UVR absorption, broad spectral coverage, exceptional photostability and low toxicity.
That said, we need to understand how these potentially new UV-filters respond to UVR when deposited on various skin models. In other words, does the light absorbing behaviour change once deposited on skin? This could affect their efficacy. The proposed programme offers a potentially transformative contribution to the marine (and health)-care vital, field of sunscreen science. The present CENTA2 is an ideal platform to support this research, given the closely aligned links between NERC Research Areas including: (1) Pollution, Waste and Resources (closely aligned); (2) Marine Environments; and (3) Environmental Microbiology, as well as being intimately aligned with one of the Sciences Themes of CENTA2, that of Climate and Environmental Sustainability. Lastly, the present project provides an ideal opportunity to link with IMCD personal care, led by Dr Laurent Blasco, IMCD’s technical director of personal care.
Fig. 1: Molecular structures of sinapoyl malate and key MAAs including the MAA precursor 4-deoxygadusol. Corresponding UV absorption spectra (relative intensities not scaled for clarity) are shown as a guide.
This project is suitable for CASE funding
HostUniversity of Birmingham
- Climate and Environmental Sustainability
- Organisms and Ecosystems
Preparation of skin models: EPISKINTM tissue models (https://www.episkin.com) will be used to test for potential irritation, penetration and toxicity of the novel UV-filters. A range of skin models, such as reconstructed human epidermis with and without melanocytes, will be tested. The models require adaptation to the compounds tested and are crucial in demonstrating efficacy and safety.
Spectroscopy: Transient absorption spectroscopy15 will be used to track energy flow in these molecules following absorption of UVR. These techniques are crucial in enabling us to build molecular-movies of energy flow over the time window of 10-15–10-3 s.
Analytical chemistry: The most promising UVR filters will be converted to a sunscreen blend (UVR- filter/moisturizer) and deposited on the various skin models. Following UVR exposure with a solar simulator, the blend will be washed off in water and contents analysed for potential photogenerated/phototoxic products.
Training and skills
Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.
The excellent Early-Career Researcher (ECR) will be trained to perform a diverse range of experiments (at Birmingham). Their contribution will be paramount to the success of this CENTA2 project. The ECR will benefit from exposure to state-of-the-art experiments, set in a much wider interdisciplinary context, which strives to address an important question relating to preserving the quality of aquatic life. No doubt this environment will offer wonderful opportunities to enhance their skills sets and their future employability.
Partners and collaboration
The proposed studies will inform industry-based researchers currently utilising ‘top-down’ methodologies to develop next generation UVR filters that combine the requirements of resilience to photodegradation and acceptably low (preferably zero) adverse effects. The PIs have taken steps to incorporate industry to this present proposal by linking with IMCD, specifically Laurent Blasco (LB), IMCD’s technical director of personal care. LB is thrilled at the opportunity to work with the CENTA2 Team, likely at Level 1, to explore the potential use of microbial based UVR filters that are less toxic, not just to humans, but to marine life.
Further details on how to contact the supervisor for this project and how to apply for this project can be found here:
To apply to this project:
- You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024.
- You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.
- Please submit your application and complete the host institution application process via: https://sits.bham.ac.uk/lpages/LES068.htm. Please select the PhD Geography and Environmental Science (CENTA) 2024/25 Apply Now button. The CENTA application form 2024 and CV can be uploaded to the Application Information section of the online form. Please quote CENTA 2024-B45 when completing the application form.
Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024.
Technique development in (1) preparing skin models; (2) ultrafast spectroscopy techniques.
Investigate nature-inspired UV-filters deposited on (and within) model skin. This may also involve adapting the current (transmission mode) transient absorption spectroscopy setup into reflection mode; in other words, transient reflection spectroscopy.
Assessing shortlisted candidate UV-filters display any toxicity effects when in a formulation and deposited on skin models.
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Additional reading regarding sunscreen science can be found at the PIs websites: