High-speed multi-channel 3-D Optical Coherence Tomography studies of the biomechanics of skin friction.

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering

Abstract

The health of the skin has profound effects on both our physical and psychological well-being. Enormous academic and commercial effort is devoted to optimising the health and appearance of skin. The barrier function of skin has been widely studied, but less well studied is its role in providing enough friction to allow us to grip and manipulate objects. Excessive friction can produce undesirable skin conditions such as chaffing and irritation in many scenarios such as wearing a respiration face mask or the skin being in contact with a damp surface. Conversely reduction of skin friction can occur in old age and compound the difficulties experienced by the older population when gripping and manipulating objects.

Many potential determinants of friction have been studied, including applied load, skin deformation, skin mechanical properties and surface textures and materials, but the sub-surface behaviour and skin strain has not been investigated as rigorously. Most of these parameters have been investigated statically and although it is known that they will change when the contact is dynamic no quantitative data is available for using in computer models of skin.

The aim in this work will be to develop new imaging techniques to allow sub-surface observation of how skin behaves when it is sliding against an object and what influences this the most, for example, skin moisture, applied load, sliding speed etc. The contact area between skin and object will also studied in greater detail than before as this has a major effect on friction and as yet no techniques exist for characterising this in a moving contact.

The objectives of the work will initially focus on developing the equipment and techniques needed to observe the surface and sub-surface behaviour. These will then be combined with skin testing apparatus to allow the measurements of friction etc. to be taken in parallel with the sub-surface images.

The information from the tests and the techniques themselves will then be applied in three practical case studies to ensure real world impact for the work. The first will involve working with Philips on studying facial masks used by sleep apnea sufferers. Test data will help improve computer models of the contact between facial skin and a mask. The second will be carried out with Unilever and focus on characterising the effects of skin creams and cleansers. The final case study will be on using the new non-invasive imaging technique in clinical studies carried out by dermatologists at The University of Sheffield to replace tape-stripping methods currently used to study skin damage.

Planned Impact

The new OCT techniques and understanding generated in this study will be used in a range of high-impact applications. These will include the development of specific, validated models, improved understanding of medical problems and the design of actual products (medical, cosmetics or general consumer goods). Academic impact has already been discussed in the Academic Beneficiaries section and there is potential for this project to impact a diverse range of academic disciplines. In addition to this, we will collaborate with industrial partners, public health organisations and charities in order to deliver the following examples of economic and societal impact criteria (as defined by RCUK):

1. Enhancing quality of life, health and well-being:
Within 20 years the largest population cohort in Europe will be those over 65. Many of the lifestyle problems affecting the elderly arise from reduced grip and feel. The data accumulated using our technology will greatly expand the currently sparse information on the physical properties of ageing skin and will help improve the design of new consumer products as well as assistive technology.
Eczema affects an estimated 5.7 million in the UK. It is particularly prevalent amongst children. Cosmetic skin treatments have an enormous impact on quality of life and their formulation could be improved using data provided by our new technology.

2. Enhancing the research capacity knowledge and skills of public, private and third sector organisations:
Written into the project are three specific impact case studies which include the involvement of the private sector (Philips and Unilever) as well as the public sector (NHS). There will also be ample opportunity to include other private and third sector organisations who can then benefit from the outcomes of the work in the future (e.g. Reckitt Benckiser, Johnson & Johnson, Devices 4 Dignity, Age UK, Diabetes UK etc.).

3. Attracting R&D investment, commercialisation and exploitation, leading to spin out companies, and the creation of new processes, products and services:
Our project will provide much greater measurement capabilities to the Philips-led UNITISS Marie Curie project and IP generated by us will thus find a natural commercial partner.
Recent government policy seeks to make the UK a centre for innovative pharmaceutical design. Our project aims to yield a unique characterisation capability for the effects of generic topical skin treatments. Combined with our world-leading capability in skin protease measurement this will attract research contracts from major pharmaceuticals companies and help to drive the development of better, safer topical treatments for many skin conditions.

4. Wealth creation, economic prosperity and regeneration:
As well as opportunities for wealth creation mentioned above, this research will also inform the design of products in the huge consumer skin care market such as shaving, either the razors or the gels/foams and products applied pre and post-shaving as well as leg waxing materials, beauty products (e.g. anti-wrinkle creams) etc.

Publications

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Liu X (2018) Measuring contact area in a sliding human finger-pad contact. in Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI)

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Liu X (2015) The contributions of skin structural properties to the friction of human finger-pads in Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology

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Maiti R (2019) Morphological parametric mapping of 21 skin sites throughout the body using optical coherence tomography in Journal of the Mechanical Behavior of Biomedical Materials

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Maiti R (2016) In vivo measurement of skin surface strain and sub-surface layer deformation induced by natural tissue stretching. in Journal of the mechanical behavior of biomedical materials

 
Description Angiographic optical coherence tomography has successfully been used to characterize in-vivo human skin in both normal subjects and those suffering from atopic dermatitis (AD - also known as eczema), which is a chronic disease associated with a defective skin barrier. There is an urgent need to characterize the benefits and risks associated with mainstay treatments of AD flares such as topical corticosteroids (TCS). TCS creams are the most effective way of dealing with painful AD flares however overuse thins the epidermis of the skin, which can provoke fear in patients. OCT has been suggested as a sensitive tool to measure epidermal thickness and thus help to understand how to safely use TCS in eczema. We have shown that conventional OCT can fail to accurately measure epidermal thickness especially during severe flares, due to excessive thickening and loss of contrast between epidermis and dermis. However we further showed that angiographic OCT can provide very precise measurements of epidermal thickness in all cases, by using label-free contrast from blood flow in small blood vessels such capillary loops and the superficial dermal plexus to provide a new biomarker for epidermal thickness.
Exploitation Route Angiographic OCT has produced significant interest in the dermatology community and skin-care industry. We would like to build on our work by investigating microvascular changes in early-onset AD and also using the technique in studies to determine the safe dosage for TCS in cases of moderate to severe AD. We have also had expressions of interest from industry in using the technique to study the effects of skin care products such as soaps and moisturizers. This interest has progressed to the point that we are currently developing clinical protocols.
Sectors Healthcare,Pharmaceuticals and Medical Biotechnology

 
Description Tools developed within this grant to characterize the skin properties of patients suffering from atopic dermatitis have generated interest among pharmaceuticals companies who wish to test new therapeutic compounds. We have begun two funded clinical trials to evaluate the use of OCT imaging in characterizing the skin of healthy controls and patients receiving a number of different therapeutic products. Funders include Leo Pharma A/S and Pfizer Inc. The thematic area of OCT imaging of atopic dermatitis, which was originally developed during this grant, has led to a substantial EPSRC HIPS grant being awarded recently.
First Year Of Impact 2017
Sector Healthcare,Pharmaceuticals and Medical Biotechnology
Impact Types Economic

 
Description IRRST standard call
Amount £719,977 (GBP)
Organisation Robert Sauv√© Research Institute in Occupational Health and Safety 
Start 02/2018 
End 09/2020