Analysis of Keratin Films as Screening Tools for Predicting the Efficacy of Potential Hair Dyes

The study explored the use of keratin films as a screening tool for predicting the efficacy of potential hair dyes. CI Acid Orange 7 dye was applied to both opaque and translucent keratin films. Time-of-flight secondary ion mass spectrometry images showed uniform dye penetration in both film types. However, ultraviolet-visible analysis indicated that the translucent film had a higher dye concentration. Scanning electron microscopy suggested that the higher porosity of the opaque film led to more dye desorption during rinsing. Thus, the translucent film was deemed a better substrate for screening new hair dyes.