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Research Article Open access CC BY 4.0

Marine-Biomass-Derived Melanin–Chitosan Composites as Natural Black Hair Colorants: Charge Reversal and Electrostatic Deposition Mechanism

Toshihiko Matsuura, Airi Nakajima

Organics · pp. 23–23 · Published 8 Jun 2026

10.3390/org7020023

Abstract

Conventional oxidative hair dyes rely on aromatic amines, raising concerns about human health and environmental safety. This study reports a natural hair-coloring system using size-controlled ink particles (SIPs, ~170 nm in diameter) from cuttlefish ink and chitosan. Because both SIPs and hair surfaces carry negative charges near neutral pH, original SIPs exhibited poor deposition onto hair. Polyelectrolyte complexation with chitosan reversed the SIP surface charge under acidic conditions (maximum ζ ≈ +41 mV at pH 2.4), enabling electrostatic deposition onto hair fibers. Dynamic light scattering (DLS) revealed pH-responsive aggregation at pH 1.6–1.8 and redispersion at pH 2.8–4.3, while ultraviolet–visible (UV–Vis) spectra confirmed that the broadband absorption of melanin was preserved, consistent with predominantly noncovalent interactions. Scanning electron microscopy (SEM) showed a particle-based composite coating on hair fibers. An optimal SIP:chitosan weight ratio of 10:1 at pH ~4.7 yielded the darkest and most uniform coloration (L* = 32.89, ΔE*ab = 55.89) without metallic mordants, achieving darker coloration than representative plant-based natural colorants reported in the literature. These results demonstrate a marine-biomass-derived approach to natural black hair coloration with strong darkening performance.

Polyelectrolyte Deposition (geology) Carbon black Materials science Scanning electron microscope Coating Chemical engineering Composite number

References (42)

  1. 1 Kim, 2016, The Use of Personal Hair Dye and Its Implications for Human Health [DOI]
  2. 2 Statista Research Department (2026, February 24). Global Hair Coloring Market Size 2022 & 2029. Available online: https://www.statista.com/statistics/972997/global-hair-color-market-value/.
  3. 3 Nohynek, 2004, Toxicity and Human Health Risk of Hair Dyes [DOI]
  4. 4 Mukkanna, 2017, Para-Phenylenediamine Allergy: Current Perspectives on Diagnosis and Management [DOI]
  5. 5 Tkaczyk, 2020, Synthetic Organic Dyes as Contaminants of the Aquatic Environment and Their Implications for Ecosystems: A Review [DOI]
  6. 6 Cui, H., Xie, W., Hua, Z., Cao, L., Xiong, Z., Tang, Y., and Yuan, Z. (2022). Recent Advancements in Natural Plant Colorants Used for Hair Dye Applications: A Review. Molecules, 27. [DOI]
  7. 7 Kalita, 2022, Formulation and Evaluation of Natural Herbal Hair Dye Gel Using Lawsonia inermis (Henna Leaves) and Skin Irritation Studies in Albino Rats
  8. 8 Boga, 2013, Investigation on the Dyeing Power of Some Organic Natural Compounds for a Green Approach to Hair Dyeing [DOI]
  9. 9 Slominski, 2004, Melanin Pigmentation in Mammalian Skin and Its Hormonal Regulation [DOI]
  10. 10 Menichetti, A., Mordini, D., Vicenzi, S., and Montalti, M. (2024). Melanin for Photoprotection and Hair Coloration in the Emerging Era of Nanocosmetics. Int. J. Mol. Sci., 25. [DOI]
  11. 11 Nguyen, 2024, Different Biocompatibility and Radioprotective Activity of Squid Melanin Nanoparticles on Human Stromal Cells [DOI]
  12. 12 Solano, F. (2017). Melanin and Melanin-Related Polymers as Materials with Biomedical and Biotechnological Applications—Cuttlefish Ink and Mussel Foot Proteins as Inspired Biomolecules. Int. J. Mol. Sci., 18. [DOI]
  13. 13 Brenner, 2008, The Protective Role of Melanin Against UV Damage in Human Skin [DOI]
  14. 14 Meredith, 2006, The Physical and Chemical Properties of Eumelanin [DOI]
  15. 15 Derby, 2014, Cephalopod Ink: Production, Chemistry, Functions and Applications [DOI]
  16. 16 Food and Agriculture Organization of the United Nations (FAO) (2024). The State of World Fisheries and Aquaculture 2024: Towards Blue Transformation, FAO. Available online: https://openknowledge.fao.org/handle/20.500.14283/cd0683en.
  17. 17 Xie, 2019, Natural Eumelanin and Its Derivatives as Multifunctional Materials for Bioinspired Applications: A Review [DOI]
  18. 18 Matsuura, 2009, Optical and Paramagnetic Properties of Size-Controlled Ink Particles Isolated from Sepia officinalis [DOI]
  19. 19 Matsuura, 2010, Electron Spin Resonance Spectroscopic Study of Size-Controlled Ink Particles Isolated from Sepia officinalis [DOI]
  20. 20 Matsuura, 2011, Paramagnetic Properties of Size-Controlled Squid Ink Particles Dispersed in Water [DOI]
  21. 21 Matsuura, 2013, Size Estimation of Biological Ink Particles Dispersed in Liquids Using Atomic Force Microscopy
  22. 22 Micillo, R., Panzella, L., Koike, K., Monfrecola, G., Napolitano, A., and d’Ischia, M. (2016). “Fifty Shades” of Black and Red or How Carboxyl Groups Fine Tune Eumelanin and Pheomelanin Properties. Int. J. Mol. Sci., 17. [DOI]
  23. 23 Wortmann, 2010, Spatial Probing of the Properties of the Human Hair Surface Using Wilhelmy Force Profiles [DOI]
  24. 24 Maddar, 2019, Nanoscale Surface Charge Visualization of Human Hair [DOI]
  25. 25 Mani, 2001, Interaction of Melanin with Proteins—The Importance of an Acidic Intramelanosomal pH [DOI]
  26. 26 Matsuura, 2019, Surface Modification of Natural Ink Particles for Hair Coloring [DOI]
  27. 27 Rinaudo, 2006, Chitin and Chitosan: Properties and Applications [DOI]
  28. 28 Guzmán, E., Ortega, F., and Rubio, R.G. (2022). Chitosan: A Promising Multifunctional Cosmetic Ingredient for Skin and Hair Care. Cosmetics, 9. [DOI]
  29. 29 Aranaz, I., Acosta, N., Civera, C., Elorza, B., Mingo, J., Castro, C., Gandía, M.D.L.L., and Caballero, A.H. (2018). Cosmetics and Cosmeceutical Applications of Chitin, Chitosan and Their Derivatives. Polymers, 10. [DOI]
  30. 30 Sionkowska, 2017, Preparation and Characterization of Collagen/Chitosan/Hyaluronic Acid Thin Films for Application in Hair Care Cosmetics [DOI]
  31. 31 Ueno, T., Taya, Y., and Shimono, I. (2010). Method for Manufacturing Cuttlefish Ink Pigment Particle. (4605354), Japan Patent.
  32. 32 Morita, 2024, Melanin Upcycling: Creation of Polymeric Materials from Melanin Decomposition Products [DOI]
  33. 33 Bernsmann, 2010, Protein Adsorption on Dopamine-Melanin Films: Role of Electrostatic Interactions Inferred from Zeta-Potential Measurements versus Chemisorption [DOI]
  34. 34 Gregory, 2011, Adsorption and Flocculation by Polymers and Polymer Mixtures [DOI]
  35. 35 Szilagyi, 2014, Polyelectrolyte Adsorption, Interparticle Forces, and Colloidal Aggregation [DOI]
  36. 36 Wang, 2006, Protonation Constants of Chitosan with Different Molecular Weight and Degree of Deacetylation [DOI]
  37. 37 Karlsson, 2016, Melanin and Neuromelanin Binding of Drugs and Chemicals: Toxicological Implications [DOI]
  38. 38 Khayrova, 2021, Obtaining Chitin, Chitosan and Their Melanin Complexes from Insects [DOI]
  39. 39 Dias, 2015, Hair Cosmetics: An Overview [DOI]
  40. 40 Sargsyan, L., Hippe, T., Manneck, H., and Vill, V. (2021). Tannin-Mordant Coloration with Matcha (Camelia sinensis) and Iron(II)-Lactate on Human Hair Tresses. Molecules, 26. [DOI]
  41. 41 Cui, 2023, Plant Colorants for Natural Hair Coloration: Dyeing Optimization and Photostability Assessment [DOI]
  42. 42 Khairova, 2022, Chitosan–Melanin Polymer Complex: A Promising Ingredient in Emulsion Compositions [DOI]

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