Reconstructed skin

The fruit of meticulous manipulations, reconstructed tissue models must have constant properties in order to guarantee repeatable and reliable tests. This production is a technical and a human prowess.

The cosmetics industry, the pharmaceutical industry and research centers, are currently using models of reconstructed tissue produced by L’Oréal’s Predictive Evaluation Center. The challenge for everyone is the same: being able to avail of stable models with the guarantee of getting a reliable response to their own tests that is repeatable over time.

In these laboratories, including 25 internal L’Oréal clients, models of reconstructed tissue are used to evaluate the innocuousness of a product, an ingredient, an active substance or a new formulation. And to measure parameters as varied as skin irritation, corrosion, sensitivity (allergies) or the ageing process, for example.

Industrially producing living material: a permanent challenge

"As we are working on living material, by definition highly diverse, cells do not always respond identically", explains Head of Production Unit. "They don’t develop in the same way at different periods of the year, for example. Moreover, the characteristics of the tissue donor we are working on also have to be taken into account". As a result, teams in the laboratories at L’Oréal’s predictive evaluation center are pursuing a constant goal: to attenuate as much as possible any differences in the same model, from one production to the next.

To do so, one of the first techniques used is to "mix" tissue (the raw materials from which the cultured cells is extracted) from four different donors. At the same time, at each stage, the product line is subject to inspection and traceability processes. "As well as using them for innocuousness tests", says the Director of Production Unit, "our models enable users to be more innovative and efficient, or even to be pioneers in a specific field of research".

Five stages of manufacture

Tissue models are manufactured according to a meticulous process that can be broken down into 5 stages:

1. Creating the collagen base

Creation of a culture support, made of collagen, to promote growth and subsequent differentiation (required for the next steps) of skin cells. The cells are deposited on a collagen membrane fixed in a mold created by the L’Oréal teams. Thirteen days later, this culture is used to reconstitute an epidermis.

2. Preparing the culture medium

The "culture medium" (liquid nutrients) comprised of a mixture of sugar, vitamins and growth hormones, is used to feed the cells during the next steps of the manufacturing process. "This step is like a farmer, for example, growing rapeseed for his livestock", explains Estelle Tinois-Tessonnaud.

3. Preparing the raw material

The raw material is comprised of cells from skin samples taken from hospitaloperating theatres (healthy surgical waste). From this sample, the epidermis, the dermis and the keratinocytes (representing 90% of the epidermis) are separated, and cultured in the nutrient.

4. Validating the cells

Five to seven days later, when the cells have developed, they are screened to validate their conformity (in particular their functionality) to the production needs of future tissue models.

5. Culturing fibroblasts

Fibroblasts are cells from the dermis that secrete the extracellular matrix components (laminin, fibronectin, collagen, etc.) and the proteins in the connective tissue.

J. Cotovio, Predictive Models & Methods

Tissue Engineering & Alternatives Methods

Agrostat 2016 is the 14th Symposium on Statistical Methods for the Food Industry (Lausanne, Switzerland 21st-24th March 2016). L’Oréal Research & Innovation was proud to sponsor this congress.

Discover our contributions for Sensometrics, Chemometrics and Risk & Process oral sessions.