How to substantiate protecting effect of hair care product on external and internal hair structure?

Hair is a constant victim of many agressions : water, sun, brushing, pollution, having shine and smooth hair with blow dryers and heating irons… The robust structure of its external layer, the cuticle, protects it. But as fantastic is this cuticle, we need to care of it…

Hair robustness comes from the cortex structure but its permeability, brightness, softness or even manageability arise from cuticle condition.

This thin layer covering the whole hair fiber protects hair shaft from mechanical and heat damages while preserving hydration that hair absolutely needs. The cuticle structure is composed by overlapping cuticle cells, as many scales, acting as a cement protecting the hair cortex.

Hair shine is mainly due to a play of light on its smooth surface. Scales wear deteriorates this surface and structure homogeneity : the reflection of light is altered and hair becomes dull.

Furthermore, when hair is damaged, these overlapping cuticle cells are disjointed and leads to another issue : they cling to each others and it becomes difficult to detangle hair. Caring about these scales is a big challenge for hair care products development.

DermoMeca®’s solutions

DermoMeca® provides a unique solution to characterize mechanical properties of hair cuticle before/after treatment with hair care products, under external factors or not.

Method: biophysical characterisation of hair with AFM (Atomic Force Microscopy)

Biological samples: hair

Readouts:

• Hair mechanical properties 
• Quantitative structural parameters (internal and external hair structure)
• Heat or treatment effect on hair biomechanical properties
• High resolution imaging of hair cuticle

Topographic images of detergent effect on hair structure.

We can notice that the detergent deteriorating overlapping cuticle cells, decreases hair stiffness.

A treatment with hair product will allow us to prove its protecting effect on hair cuticle.

Hair topographic imaging coupled to tomographic data. Echelle: red = stiff and blue = soft

CONCLUSION

Combining AFM High Resolution Imaging and 3D reconstruction of quantitative data, DermoMeca® solutions provide scientific and innovative claims on hair structure under external factors.