  Amphiphilic molecules and their self-assembled structures have long been the
target of extensive research due to their potential applications in fields
ranging from materials design to biomedical and cosmetic applications.
Increasing demands for functional complexity have been met with challenges in
biochemical engineering, driving researchers to innovate in the design of new
amphiphiles. An emerging class of molecules, namely, peptide amphiphiles,
combines key advantages and circumvents some of the disadvantages of
conventional phospholipids and block-copolymers. Herein, we present new peptide
amphiphiles comprised of an intrinsically disordered peptide conjugated to two
variants of hydrophobic dendritic domains. These molecules termed intrinsically
disordered peptide amphiphiles (IDPA), exhibit a sharp pH-induced micellar
phase-transition from low-dispersity spheres to extremely elongated worm-like
micelles. We present an experimental characterization of the transition and
propose a theoretical model to describe the pH-response. We also present the
potential of the shape transition to serve as a mechanism for the design of a
cargo hold-and-release application. Such amphiphilic systems demonstrate the
power of tailoring the interactions between disordered peptides for various
stimuli-responsive biomedical applications.
