Nanoscale double emulsions stabilized by single-component block copolypeptides

• Published in: Nature 2008-09, Vol.455 (7209), p.85-88
• Main Authors: Hanson, Jarrod A, Mason, Thomas G, Deming, Timothy J, Graves, Sara M, Chang, Connie B, Li, Zhibo
• Format: Article
• Language: English
• Subjects: Aminoacid polymers; Applied sciences; Chemistry; Colloidal state and disperse state; Cosmetics; Double emulsions; Droplets; Emulsions; Emulsions - chemistry; Emulsions. Microemulsions. Foams; Exact sciences and technology; General and physical chemistry; Humanities and Social Sciences; letter; Microfluidics; Microscopy, Electron, Transmission; Microscopy, Fluorescence; multidisciplinary; Nanocomposites; Nanomaterials; Nanostructure; Nanostructures - chemistry; Nanostructures - ultrastructure; Nanotechnology; Peptides; Peptides - chemistry; Physicochemistry of polymers; Polypeptides; Properties; Pyrenes - chemistry; Quantum dots; Scattering, Radiation; Science; Science (multidisciplinary); Solubility; Surface-Active Agents - chemistry; Surfactants; Synthetic biopolymers; Transmission electron microscopy; Water
• ISSN: 0028-0836; 1476-4687; 1476-4679
• DOI: 10.1038/nature07197

Water-in-oil-in-water emulsions are examples of double emulsions, in which dispersions of small water droplets within larger oil droplets are themselves dispersed in a continuous aqueous phase. Emulsions occur in many forms of processing and are used extensively by the foods, cosmetics and coatings industries. Because of their compartmentalized internal structure, double emulsions can provide advantages over simple oil-in-water emulsions for encapsulation, such as the ability to carry both polar and non-polar cargos, and improved control over release of therapeutic molecules. The preparation of double emulsions typically requires mixtures of surfactants for stability; the formation of double nanoemulsions, where both inner and outer droplets are under 100 nm, has not yet been achieved. Here we show that water-in-oil-in-water double emulsions can be prepared in a simple process and stabilized over many months using single-component, synthetic amphiphilic diblock copolypeptide surfactants. These surfactants even stabilize droplets subjected to extreme flow, leading to direct, mass production of robust double nanoemulsions that are amenable to nanostructured encapsulation applications in foods, cosmetics and drug delivery.