Purpose: Hair lipids can contribute to physicochemical phenomena such as diffusion, cell cohesion and mechanical strength, although lipids occur at much lower levels (1-6% dry weight) than proteins (>90%).Hair lipids can be diminished by hair washing and submission to chemical treatments. Studies have shown that internal wool lipids (IWL) resemble those membranes of other keratinic tissues such as human hair or stratum corneum.
Results: In this work, the IWL, in the form of liposomes or from an emulsion system, were applied to untreated hair fibres and also treated hair fibres. The results showed that application of IWL to pretreated hair samples lead to an improvement in mechanical strength properties of the fibres when the IWL were applied structured as liposomes. Differential scanning calorimetry studies demonstrated that the application of IWL to pretreated hair sample led to a slight increase in the crystalline material of the fibres. Moreover, scanning electron microscopy studies showed that application of IWL liposomes to damaged hair fibres lead to an improvement of the cuticle scale, demonstrating the importance of the use of a delivery vehicle with a bilayer structure similar to the one present in the hair fibre to restore the natural properties of the fibre.