Controlled release and entrapment of enantiomers in self-assembling scaffolds composed of beta-sheet peptides.

As a first step toward utilizing self-assembling peptide scaffolds to create tunable matrices for drug delivery, peptide RADAFI and RADAFII, containing the same amino acid composition but different positions of one phenylalanine residue, scaffolds were prepared for controlled release of chiral enantiomers. The release behaviors depended on the network nanostructures and the guest chirality and were well tailored via loading different amounts of guests. This contribution addressed the relationships among the peptide sequence, the network nanoarchitecture, and the controlled release. RADAFII systems provided a means of controlling the release kinetics for L- and D-phenylalanine, which was achieved through the facile pi-pi stacking between the aromatic rings of L-isomer and those in RADAFII sequence and through the appropriate scaffold nanoarchitecture. The concept of controlled release for enantiomers via dominating the network nanostructures can also be harnessed in the de novo design of delivery systems with specific structural features for some special biomolecules.