Human Hair Keratin Direct Electrochemistry and In Situ Interaction with p‐Toluenediamine and p‐Aminophenol Hair Dye Precursors using a Keratin Electrochemical Biosensor

Abstract

Keratin is the main protein in hair strands. The process of dyeing hair with permanent dyes is quite complex and involves oxidative reactions between precursors, such as p‐toluenediamine (PTD) and p‐aminophenol (PAP), and coupler agents, in alkaline and oxidative medium, inside the hair. The electrochemical behaviour of native and denatured human hair keratin, assessed by using a keratin multilayer film adsorbed on glassy carbon electrode, and its interaction with hair dye precursors, PTD and PAP, by using electrochemical techniques, was investigated. Native and denatured keratin electrochemical oxidation showed two oxidation peaks; the first was first attributed to the cysteine amino acid residues, and the second to the cysteine and methionine amino acids residues. The PTD‐ and PAP‐keratin‐hair dye interactions induced damage, causing the unfolding of the keratin morphological structure, and new additional peaks of the cysteine and tyrosine amino acid residues were revealed.

Polyphenols Coordinated with Cu (II) in an Aqueous System Build Ion-Channel Coatings on Hair Surfaces

“…Most commercial chemical dyes contain bleaching agents such as ammonia and peroxide [ 15 , 16 , 17 ]. During the hair-dyeing process, bleaching agents first damage the outermost cuticle layer of the hair and push chemical colors such as p-Phenylenediamin (PPD), o-Phenylenediamine (OPD), and m-Phenylenediamine (MPD) to enter the cortex layer [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ].…”

MnO2–DNA nanomaterials toward the dual signal detection of P-aminophenol micropollutants

“…2,3 Relevant studies have reported that a prolonged human exposure to PAP-contaminated water and soil can cause human skin allergy and respiratory system damage. 4 When PAP enters the human body, it combines with hemoglobin in the blood and converts it into methemoglobin, 5 which does not have the ability to carry oxygen, thus causing damage to the human respiratory system. In severe cases, it can cause irreversible damage to vital organs such as the kidneys and liver.…”