Biocompatible Self-assembly Coating for Safe Hair Dyes with Antimicrobial and Antiadhesion Potential

Abstract Hair dyeing has emerged as an integral part of the cosmetic industry, driving the demand for natural, safer, and malodor-free alternatives to traditional p-phenylenediamine-based hair dyes. Herein, leveraging the deposition capability of plant-derived quinones on substrate surfaces, an AC-Zn2+ coating is synthesized via a one-step self-assembly process involving alizarin (AL), zinc ions (Zn2+), and cinnamaldehyde (Cin) for hair coloring. The AC-Zn2+ coating-based dyes not only exhibit effective coloring on bleached or natural gray hair but also demonstrate good durability under repeated washing without obvious color fading. Crucially, hair samples dyed with AC-Zn2+ show additional favorable properties, including antibacterial activity (nearly 100% inhibition efficacy against Staphylococcus aureus), antiadhesion performance for Malassezia furfur and Staphylococcus epidermidis, antistatic behavior, and pleasant aroma, aligning with the emerging trend of multifunctional and eco-friendly hair dyes. Moreover, this quinone-based coating achieves a satisfactory dyeing effect in mice and displays excellent biological safety across various models, including cells, zebrafish, mice, and bean sprouts. These features underscore the potential of AC-Zn2+ as a high-end hair dye that poses no obvious toxicity under the conditions of this study while enabling enhanced hair functionality.