Project Highlights:

• To develop novel biosynthetic procedures for producing environment-friendly UV sunscreens

• To characterise UV sunscreens with state-of-the-art analytical (laser based) techniques

• To correlate structure-dynamics-function of sunscreens using theory and computation


Cases of cosmeceuticals interfering with marine life are now widespread. This is largely due to

increasing societal trends towards exposure to ultraviolet radiation (UVR) from sunlight. Sunscreens

provide UVR-protection; however, this often comes at a cost as the desired sun protection factor (SPF)

is achieved with high concentrations of UVR filters within a blend. This can lead to serious

environmental issues. For example, some sunscreens are known to be damaging to marine life [1,2];

indeed Hawaii, will ban the use of certain UVR filters (e.g. oxybenzone) in sunscreen blends due to

coral bleaching [3]. It is therefore key to develop next generation, safer sunscreens which preserve

the quality of aquatic life.

The proposed CENTA2 project seeks to answer the overarching question: Can microorganism (e.g.

algae, cyanobacteria etc.)-based UVR filters be chemically modified for human use, that combine the

resilience to UVR exposure and, importantly to the ethos of NERC, are much safer to the environment?

Three researchers within the University of Warwick (UoW) spanning Chemistry, Life Sciences and

Centre for Scientific Computing, along with Lubrizol, a leading skin-care industry, propose to apply

their complementary skills in experiment and theory to train a highly talented early career researcher

to confront the multi-facetted challenges imposed by this question.

The proposed programme offers a potentially transformative contribution to the photophysically

fascinating, and 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 Lubrizol’s division of Skin Care, led by Professor Laurent Blasco, Honorary

Professor at the University of Warwick and Lubrizol’s global skin care manager.

Four panels serve to represent the workflow of this CENTA2 project. Whilst each panel
represents a specific research objective (see methodology), these are not mutually exclusive, and
contain extensive cross-talk to ensure the ambitious aim of the CENTA2 project is realised.


Theory and computation: steady-state calculations will employ TD-DFT [4,5]/CASPT2 [6,7] to yield

details of molecular structure of UVR filters, while dynamics simulations will use trajectory surface

hopping methods and solvation models to compute photorelaxation dynamics in solution/condensedphases.

Biosynthesis: The UVR filters will involve bacterial expression, purification and characterisation.

Bacterial production of these nature-derived systems will be based on well established procedures as

discussed in REFS [8] and [9].

Spectroscopy: Transient absorption spectroscopy [10] will be used to track energy flow in these

molecules following absorption of UVR. These techniques are crucial in enabling us to build molecularmovies

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 (UVRfilter/

moisturizer) and deposited on skin model VITRO-SKINR [11]. Following UVR exposure, the blend

will be washed off in water and contents analysed for potential photogenerated/phototoxic products.

Training and Skills

The excellent Early-Career Researcher (ECR) will be trained to perform a diverse range of experiments

(at Warwick and Lubrizol (Analytical chemistry-see above)), complemented by high-level calculations.

Their contribution will be paramount to the success of this CENTA2 project. The ECR will benefit from

exposure to state-of-the-art experiment and theory and computation capabilities, 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.


Year 1: Establishing a tool box in a range of theory, biosynthesis, spectroscopy and analytical chemistry techniques. Trial chemical structures of nature-based UVR-filters predicted through theory.

Year 2: Bacterial synthesis of UVR-filters and subsequently tracking energy flow in these systems using transient absorption spectroscopy.

Year 3: Shortlist of candidate nature-based UVR-filters to be tested for long term photostability. Photogenerated and phototoxic products, following solar illumination, will be identified through analytical chemistry-based techniques.

Partners and collaboration (including CASE)

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. Stavros (PI) has already taken

steps to incorporate industry by linking with Lubrizol, specifically Laurent Blasco (LB), global skin care

manager at Lubrizol and Honorary Professor at Warwick. 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

Professor Vasilios Stavros

Department of Chemistry

University of Warwick