Disentangling melanin self-assembly via nanoprecipitation: from protoparticles to supraparticles
Meera Madhu1, Adithya Vaidyanathan1, Bárbara Fornaciari1
1Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA. kohler@chemistry.ohio-state.edu.
Nanoscale
|January 20, 2026
Summary
Researchers developed a new method to control melanin nanostructure by aggregating small melanin particles into larger, stable supraparticles. This technique precisely tunes size for future structure-function studies of this natural nanomaterial.
Area of Science:
- Materials Science
- Nanotechnology
- Biochemistry
Background:
- Eumelanin's properties are sensitive to particle size and morphology.
- Previous methods struggled to separate melanin polymerization from self-assembly.
Purpose of the Study:
- To introduce a post-synthetic method for controlling melanin nanostructure.
- To create size-tunable melanin supraparticles for structure-function studies.
Main Methods:
- Utilized an organic antisolvent nanoprecipitation approach.
- Aggregated ultrasmall, disc-like melanin particles (2-6 nm) into spherical supraparticles (30-100 nm).
- Dialysis to remove solvent, yielding stable supraparticles.
Main Results:
- Achieved size-controlled melanin supraparticles (30-100 nm).
- Supraparticles demonstrated excellent stability to heat, sonication, and remained constant in water for two weeks.
- Stability attributed to self-crosslinking covalent bonds between subunits, accelerated by UV irradiation.
Conclusions:
- The nanoprecipitation method precisely manipulates melanin's hierarchical structure.
- This approach enables detailed structure-function investigations of eumelanin's emergent properties.
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