Brazilian scientist received the international award The 2017 Lush Prize, organized by the cosmetics company Lush. Carolina Motter Catarino conducted a doctoral research at the Rensselae Polytechnic Institute in the United States and discovered the possibility of doing cosmetic tests without using animals. Carolina reconstructed an in vitro human skin model for toxicity testing, and the initial study was conducted with the guidance of Professor Silvya Stuchi at the Faculty of Pharmaceutical Sciences (FCF) at University of São Paulo – USP.

Cosmetic tests on animals are no longer allowed in some countries, including Brazil. “First of all, animals are physiologically very different from humans, such as the composition and structure of skin layers and concentration of hair follicles. These and other differences may produce results that are not reproduced in humans later or even not anticipated possible adverse effects, “says the researcher.

Skin models similar to human skin were used and validated with parameters of specific effects, such as irritation or corrosion. “Most of these models have one or at most two types of cells among the more than 15 types that exist in the skin of humans,” she says “and they do not have vasculature and appendix, such as hair follicles, sweat glands and sebaceous glands”, added.

To make the impression, Carolina used human cells from skin samples removed in plastic surgeries or postectomy when the foreskin is removed. The scientists say that the samples used are usually from newborn foreskins because the cells have a better potential for expansion and differentiation compared to cells isolated from adult skin samples. “After isolating the cells, they are expanded in vitro so as to generate enough cells to rebuild the skin,” she says.

The next step is to prepare several biological paints, called “bio-inks”. The dyes are composed of a mixture of proteins in our skin, such as collagen I, in addition to previously isolated cells, such as fibroblast, keratinocytes and melanocytes.

With the inks separate, they are inserted into cartridges to be placed in the printer. Carolina says that once printed, the skin samples remain in a 12-21 day incubator to differentiate layers of skin. “After this period, the skin is similar in structure to human skin and can be used, for example, to assess irritant or corrosive potential, among others, of substances applied topically,” she describes.

Carolina started her skin studies in vitro while still studying Bioprocess Engineering and Biotechnology at UFPR (Federal University of Paraná). The researcher even participated in an exchange program, studying at the Université de Technologie de Compiègne, France, and attending a intern program the cosmetic company L’Óreal in Paris.
Source: University of São Paulo – USP