Keratin-Chitosan Microcapsules via Membrane Emulsification and Interfacial Complexation

Amy Wilson, Ekanem E. Ekanem, Davide Mattia, Karen J. Edler, Janet L. Scott

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9 Citations (SciVal)
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The continuous fabrication via membrane emulsification of stable microcapsules using renewable, biodegradable biopolymer wall materials keratin and chitosan is reported here for the first time. Microcapsule formation was based on opposite charge interactions between keratin and chitosan, which formed polyelectrolyte complexes when solutions were mixed at pH 5.5. Interfacial complexation was induced by transfer of keratin-stabilized primary emulsion droplets to chitosan solution, where the deposition of chitosan around droplets formed a core-shell structure. Capsule formation was demonstrated both in batch and continuous systems, with the latter showing a productivity up to 4.5 million capsules per minute. Keratin-chitosan microcapsules (in the 30-120 μm range) released less encapsulated nile red than the keratin-only emulsion, whereas microcapsules cross-linked with glutaraldehyde were stable for at least 6 months, and a greater amount of cross-linker was associated with enhanced dye release under the application of force due to increased shell brittleness. In light of recent bans involving microplastics in cosmetics, applications may be found in skin-pH formulas for the protection of oils or oil-soluble compounds, with a possible mechanical rupture release mechanism (e.g., rubbing on skin).

Original languageEnglish
Pages (from-to)16617-16626
Number of pages10
JournalACS Sustainable Chemistry and Engineering
Issue number49
Early online date1 Dec 2021
Publication statusPublished - 13 Dec 2021

Bibliographical note

Funding Information:
The authors would like to thank the EPSRC for funding this project (grant EP/P027490/1).


  • biopolymer
  • chitosan
  • coacervation
  • keratin
  • layer-by-layer
  • membrane emulsification
  • microencapsulation
  • polyelectrolyte complex

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment


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