The invention relates to nanoemulsions useful for analytical techniques and delivery of cargoes such as pharmaceutically active agents. In particular, the invention relates to nanoemulsions comprising an oil phase dispersed in an aqueous phase and at least two peptide surfactants adsorbed at the liquid-liquid interface, one peptide surfactant comprising a short peptide sequence having α-helical propensity and at least one second polypeptide surfactant comprising at least two peptide sequences having α-helical propensity linked by a linking sequence of 3 to 11 amino acid residues. Optionally the at least one second polypeptide surfactant comprises at least one pharmacokinetic modifying agent and/or a targeting agent. Furthermore, the nanoemulsion may further comprise a cargo such as a pharmaceutically active agent.