Hair is a complex heterogeneous system containing proteins and lipids that are easily damaged by chemical reactions. A vast majority of such reactions involve free radical intermediates. Hair damage can be triggered photochemically (e.g., when you go out on a sunny day), chemically (e.g., during bleaching or dyeing) or thermally (e.g., flat ironing). The mechanisms of radical processes in hair, however, are poorly understood. For instance, there is some anecdotal evidence that sebum (a natural oil in the skin and scalp containing a range of unsaturated compounds) accelerates hair damage but the mechanism of its pro-oxidant action is unknown.
This project aims at unravelling the mechanisms of radical reactions in hair, with particular focus on the role of sebum. We will consider a range of possible reaction pathways including accumulation of reactive hydroperoxides in sebum which could lead to accelerated hair damage. Understanding this chemistry will help us develop strategies for protecting hair from free radical damage in the future.
In order to identify the most important mechanistic pathways in hair damage, we will start with simple model systems which mimic hair constituents (e.g., protected amino acids, lipids, simple peptides, gels) and sebum (squalene, unsaturated fatty acids). The model systems will be exposed to reactive species (singlet oxygen, ozone, hydroxyl radical), and the products and intermediates will be characterised using a range of techniques including mass spectrometry (MS). Free radicals will be detected using spin trapping and EPR spectroscopy, and a new MS spectrometry-based method recently developed in our laboratory. The mechanistic understanding thus obtained will be confirmed by experiments with real hair. We will also explore the feasibility of reducing hair damage by using antioxidants and other additives that target pro-oxidant action of sebum.
Although some mechanistic features of radical reactions in biology are well established, there are many unanswered questions. In particular, reactions in systems with several chemically-distinct environments (e.g., transparent fluid sebum and coloured hair fibres) have hardly been investigated. Dead tissue such as hair is well-suited for such studies. The findings of this project will be important for cosmetic industry, as hair damage leads to dry and brittle hair that is easy to break and difficult to style, and understanding of how to avoid this damage will result in better products. We believe, however, that our results will also have important implications for a range of radical processes in biological systems.
The project will involve mechanistic organic chemistry, EPR spectroscopy, mass spectrometry and other analytical methods. There may be a small synthetic organic chemistry component. The project is thus very interdisciplinary and will provide a unique opportunity to learn and practice a variety of techniques to obtain mechanistic understanding. The project is co-sponsored by Procter and Gamble and the student will greatly benefit from the industrial collaboration. We have a strong track record of successful collaborative projects with Procter & Gamble. All Chemistry research students have access to our innovative Doctoral Training in Chemistry (iDTC): cohort-based training to support the development of scientific, transferable and employability skills: https://www.york.ac.uk/chemistry/postgraduate/idtc/
Equality, Diversity and Inclusion
The Department of Chemistry holds an Athena SWAN Gold Award and is committed to supporting equality and diversity for all staff and students. The Department strives to provide a working environment which allows all staff and students to contribute fully, to flourish, and to excel: https://www.york.ac.uk/chemistry/ed/.
For more information about the project, click on the supervisor's name above to email the supervisor. For more information about the application process or funding, please click on email institution
This PhD will formally start on 1 October 2022. Induction activities may start a few days earlier.
How to Apply
To apply for this project, submit an online PhD in Chemistry application: https://www.york.ac.uk/study/postgraduate/courses/apply?course=DRPCHESCHE3
You should hold or expect to achieve the equivalent of at least a UK upper second class degree in Chemistry or a related subject. Please check the entry requirements for your country: https://www.york.ac.uk/study/international/your-country/