Beauty Innovation
What’s required to produce bioprinted human skin in labs, at scale?
According to Nathalie Seyler, head of Episkin, the launch is only years away.
5 Jun 2024

Nathalie Seyler has been working for L’Oreal for 25 years. She’s head of the beauty giant’s subsidiary EPISKIN, a world leader in tissue engineering that offers Human Reconstructed Tissues to the global scientific community — academic and industry — to support research and development activities in safety and efficacy. The work with reconstructed skin models and skin technology started more than 40 years ago. At the same time, the company teamed up with hospitals and clinics, aiming to develop the first human epidermis. 

— We shared technologies with each other in order for them to get more robust skin grafting to treat burned people, she says. We then continued by adding other types of cells such as melanocytes. This way, we could represent the diversity of skin tones and have specific models with phototypes II, IV and V to test different molecules. Skin colour is characterised in dermatological and cosmetic research through different types of classifications such as the Fitzpatrick scale, spectrometry and colourimetry skin colour identifications. The Fitzpatrick scale is a classification for human skin colour linked to the skin response to UV. It goes from phototypes I (palest skin) to VI (darkest skin). We are able to reconstruct phototypes II, IV and V.

— Just recently, we were also able to test melasyl, which is a molecule created by L’Oréal to treat hyperpigmentation. What’s been important is also to share this technology. Today it’s used by not only us but also but it’s sold and shared with other cosmetic companies, the pharmaceutical industry, and universities — within the entire scientific community.

L’Oréal also became interested in pathological skin, and to use tech to create so-called patterned skin.

— We used bioprinting to create it and were able to reproduce lesions of atopic dermatitis by bioprinting healthy skin on one side. On the other side, we bioprinted atopic dermatitis skin. This way, we can assess specific treatments suitable for atopic patients in vitro models. Without the tech, we wouldn’t be able to do that.

— The next step was to get further by using other bioprinting technologies. You can do it through extrusion, but also using electro-spinning or meltelectro-writing. It’s a lot of barbaric words that will help us to do metrics that are closer to what we have in our skin.

Earlier this year, L’Oréal unveiled a breakthrough in its bioprinting research project together with Oregon University. 

— They used meltelectro-writing technology to do a matrix dermis, to get a full thickness model — the epidermis and the dermis — in only 18 days. This is a revolution; it usually takes much longer to get a mature full thickness, and this technology can help us to shorten the maturity of the model. They developed a special scaffold where the fibroblast — the cells of the dermis — create a really good cocoon habitat where they feel so well that they are going to produce a new matrix by themselves — the same matrix that you have in your own dermis. This way, you’re going to be able to have a reconstructed skin model that mimics the full human skin. This type of tools can also help to get skin grafting earlier for people, to treat burned people or specific skin conditions for patients. It’s going to pave the way to use this technology for skin grafting, Seyler states. She continues:

— We do have a lot of ideas and so do other people. When we read articles and find interesting things (regarding bioprinting, Ed’s note), we make sure to contact them, so we’ve partnered with a lot of industries, startups, and companies. What links us when we sign a collaborative partnership is to help people through science. Getting in touch with the right people can advance science for us but also for other purposes. The technology behind this is usually biology tech, which could be useful for very different domains.


What are the main reasons for you to put so much effort in it?

— It’s a combination. At the beginning, it was to reduce and eliminate animal testing but also to bring new tools to scientists. We’ve also worked on Xeroderma Pigmentosum — a disease with hypersensitivity to the sun — and did testing to decipher how skin reacts to the sun in extreme conditions. We also made these models available for scientists, so that they could study this pathology. We also learned a lot, about how the skin reacts, and it was interesting to share stuff with people which could be helpful in their studies.

— Since 1989 we have created beauty without animal testing, so now it’s about helping people. By knowing the physiology and the biology of skin better, we can develop cosmetic treatments for our consumers, which can be interesting solutions also for dermatology, for skin diseases, and treating burned people. Even if it’s not helping right now, we know that it can have an impact later on.

How do you do the actual bioprinting of the skin? And what have been the main challenges throughout your 20 years?

— To bioprint human skin we use bio-inks and human cells through bioprinters with different technologies such as inkjet, extrusion, and electrospinning. We are then able to create the different skin layers as well as designing specific scaffolds suitable for reconstructing skin, Seyler explains, continuing,

— The hardest part is reproducibility. What we are working on is biological samples. It’s nature, so it can change, making it a real challenge. The next challenge will be how to grow hair on the bioprinted skin, and how we’re bringing vascularisation in a stable way, which is really tricky and what we’re working on with our partners. It will make a big difference in how we test in vitro and how we can help hospitals treat specific skindom conditions or burned people through skin grafting.

Where are you now in the development of bioprinted skin?

— It’s still in pilot scale. The next step is to make it available on a larger scale, which I think will take a few years. Today, the majority of burned people are treated through manually reconstructed skin. However, a French hospital is using technology that we developed together through a collaboration 20 years ago, which has come to the market now, to help burned people. We have to keep in mind that developing a medication takes time; it has to be efficient, but it also has to be safe.

What have you developed that this French hospital is using now?

— Human epidermis. It sounds simple, but it’s not, to do it safely so that people can go back to a normal life with a new epidermis.

— Another coming step that we have in mind is to use specific polymers that can be biodegradable to be grafted directly on the burned people. This way, they could use the grafting forever.

What are the next steps here before it reaches the market?

— Safety, reproducibility, and stability. It’s going to take time but now, we’ve showed with this article (together with Oregon University) that it’s possible.

L’Oréal has also announced that in a few years, they might be able to present a bioprinted skin that can feel. This, Seyler explains, obviously comes with other challenges, such as neuro perception; to make skin cells and neuron cells coexist together. 

— To culture them outside of the body is another challenge. Without the tech we’ve developed, we will never be able to do it!

Nathalie Seyler.