Self-assembling surfactant-like peptide A(6)K as potential delivery system for hydrophobic drugs

BACKGROUND: Finding a suitable delivery system to improve the water solubility of hydrophobic drugs is a critical challenge in the development of effective formulations. In this study, we used A(6)K, a self-assembling surfactant-like peptide, as a carrier to encapsulate and deliver hydrophobic pyrene. METHODS: Pyrene was mixed with A(6)K by magnetic stirring to form a suspension. Confocal laser scanning microscopy, transmission electron microscopy, dynamic light scattering, atomic force microscopy, fluorescence, and cell uptake measurements were carried out to study the features and stability of the nanostructures, the state and content of pyrene, as well as the pyrene release profile. RESULTS: The suspension formed contained pyrene monomers trapped in the hydrophobic cores of the micellar nanofibers formed by A(6)K, as well as nanosized pyrene crystals wrapped up and stabilized by the nanofibers. The two different encapsulation methods greatly increased the concentration of pyrene in the suspension, and formation of pyrene crystals wrapped up by A(6)K nanofibers might be the major contributor to this effect. Furthermore, the suspension system could readily release and transfer pyrene into living cells. CONCLUSION: A(6)K could be further exploited as a promising delivery system for hydrophobic drugs.