Electrospinning of Self-Assembling Oligopeptides into Nanofiber Mats: The Impact of Peptide Composition and End Groups.

Low-molecular-weight oligopeptides can be electrospun into nanofiber mats. However, the mechanism underlying their electrospinnability is not well-understood. In this study, we used solid-phase peptide synthesis to produce the oligopeptide FFKK, to which the aromatic end-capping groups naphthalene, pyrene, and tetraphenylporphyrin were attached. Nuclear magnetic resonance, circular dichroism, and electrospray ionization mass spectrometry were used to characterize the oligopeptide structures. We investigated the effect of end-caps and oligopeptide concentration on their self-assembly as well as on their electrospinnability in fluorinated solvents. All oligopeptides with aromatic end-caps were amenable to electrospinning. Attenuated total reflectance Fourier transform infrared spectroscopy and microrheology results support the hypothesis that at sufficiently high concentrations, the self-assembled structures interact strongly, which facilitates electrospinning. Moreover, the results from this fundamental study can be extended to nonpeptidic small molecules possessing strong intermolecular interactions.