making microbiology easy

Exploration of skin microbiota

Supporting projects linked to skin microbiota

Smaltis supports your programs targeting the skin microbiota, to help you select the best candidates and evaluate their impact on the skin bacterial ecosystem.


Present by the billions in our body, ten times more numerous than human cells, bacteria form a real ecosystem called “microbiota”. Several studies have shown that the colonization of the skin by trillions of micro-organisms contributes to its protection against external aggressions and keeps it in good health. What is called the “stratum microbium” is an integral part of the skin, as complex and indispensable interactions are established between bacteria and skin cells. Many more studies are needed to explore these populations and their key roles in maintaining skin homeostasis. Understanding these interactions is a real challenge for developing products designed to ensure the proper balance of this flora and adapted to the specificities of each individual. This vast subject of exploration is still in its infancy.

In this context, Smaltis offers you a tailor-made service to study the impact of compounds on the skin bacterial flora of thanks to different complementary models and protocols specifically adapted to the project. Based on a solid scientific foundation, Smaltis strives to provide a complete and relevant analysis and to obtain the most reliable results possible.

Tested products

Active ingredients and finished products restoring or protecting the skin and hair microbiota. :

Prebiotics – Probiotics – Postbiotics – Preservatives – Formulas

Our offer

Screening of candidates thanks to in vitro and ex vivo studies


  • Bacterial culture et co-culture – available strain collection
  • Cellular models – keratinocytes, fibroblasts, melanocytes…
  • Reconstructed human 3D tissues colonized by live bacteria or bacterial secretome after short or long term exposure – reconstructed epidermis, reconstructed pigmented epidermis, altered skin models, immunocompetent models (3D tissues co-cultured with THP-1 monocytes), full thickness reconstructed skin



Genomic, transcriptomic, proteomic and physiological studies are performed to describe the bacterial and skin response: diversity, viability and behavior of bacteria, biofilm formation, over-expressed genes, activated metabolic pathways, cytotoxicity, physiology of the skin tissue…

Different markers can be studied in response to the modulation of the microbiota. These parameters allow the analysis of skin barrier function, hydration, homeostasis, aging, pigmentation, inflammation, immune response, oxidative stress…

These steps are necessary to select the most promising candidates for clinical studies, and to anticipate their effects on bacteria (inhibitory power against pathogenic species, stimulatory power of beneficial strains, etc.) and on skin response.

Clinical trials: from volunteer to microbiota

In vivo, a complete service makes it possible to test, on a cohort of volunteers, the clinical impact of active ingredients or finished cosmetic products, and their effects on the cutaneous bacterial flora, in the context of an imbalanced or normal skin.

For studies on healthy volunteers, Smaltis collaborates with Skinexigence, a company specialized in the evaluation of the clinical efficacy of cosmetic products under the supervision of a dermatologist. The proximity of the company makes it easy to combine biometrological measurements (fringe projection, photography, thermography, video-capillaroscopy, laser Doppler imaging, ultrasound, etc.) and microbiota characterization. Volunteers are recruited according to well-defined criteria (age, skin type, degree of hydration, etc.), and are then welcomed at the Skinexigence premises where the various evaluations and microflora samples are performed. These are systematically carried out by the same Smaltis microbiologist and processed in a very short period of time to ensure the reproducibility and reliability of the results.

For studies on volunteers suffering from skin pathologies, the service is also possible, for example by sending DNA sampling kits to the company conducting the studies on the subjects.

Sequencing with qualified providers

The composition of the bacterial flora of each sample is then determined by high-throughput NGS (Next Generation Sequencing) of the nucleic acids from the samples. This sequencing can focus on the analysis of the DNA coding for the 16S region of the bacterial ribosome (16S sequencing of the V1-V2-V3 regions), or can focus on the analysis of the total bacterial DNA contained in the sample (shotgun sequencing). From the generated metagenomic data, a statistical analysis is performed to provide a comparative, quantitative and qualitative study of the cutaneous bacterial population (diversity, relative abundance…).

Metranscriptomic profiling can also be performed to analyze gene expression and identify specific activated metabolic pathways.

Post-metagenomic exploration

Beyond the sequencing and quantitative/qualitative analysis of these bacterial populations, Smaltis strives to go as far as possible in the exploitation of the results.
The Smaltis team of microbiologists seeks to explain the data obtained, to establish correlations with the literature and the clinical phenomena observed, to understand the interactions between a compound and skin bacteria and their impact, to anticipate the effect of a variation in bacterial population on the production of metabolites… 



  • Rarefaction curves
  • Global analysis of the bacterial landscape at different taxonomic levels (relative abundance)
  • Abundance & richness study at different taxonomic levels: Chao1, Shannon, Simpson index
  • Analysis of mean reads number & evolution between different groups and overtime
  • Distance analysis: Bray-Curtis PCoA & Jaccard PCoA, Pearson Heat map, perManova
  • Deep analysis on species impacted: correlation with literature and explanation of evolution
  • Applications


    Explain the interactions between bacteria and the skin
    Understand the impact of products on skin flora
    Identify specific properties & biomarkers

    Correlation with clinical parameters
    Study specific bacterial populations
    Study of skin pathologies – atopic dermatitis, psoriasis, eczema, dandruff, sensitive skin, rosacea…


    Preserves the skin microbiota, respects the microbial ecosystem of the skin, restores the microbial function of the skin, microbiome-friendly, rebalances the dysbiosis of the skin flora, restores the natural balance of the skin, compensates for the impact of aggressive products on the skin microbiota…

    Example of achievement


    Study of the effect of an extract of Halymenia durvillei on the microbiota of sensitive and reactive skin: Characterization of Reactive and Sensitive Skin Microbiota: Effect of Halymenia durvillei (HD) Extract Treatment.
    Extract developed by Greentech.