Study of the keratinization process in human hair follicle by X-ray microdiffraction

Synchrotron X-ray micro-diffraction studies along the follicle and the hair fibre allowed us to follow the keratinization process and the progressive organization of the keratin: i) molecular organization appeared progressive ly in the follicle; the formation of alpha-helices was completed inside the follicle. ii) supramolecular organization appeared only outside the follic le, far from the bulb; filament structure was observed far from the follicl e. Comparisons between structures observed for in vitro and in vivo grown h air, whatever in the bulb or in the fibre, indicate there is no evidence of any structural difference. More, no variation in the transition in vivo/in vitro zone has been observed. In vitro and in vivo fibres exhibited the sa me structure.