Programmable Steric Control of Collagen Peptide-to-Fiber Assembly

Peptide-based collagen-mimetic materials have drawn growing interest as fibrillar collagen surrogates due to their accessibility and versatility. However, an efficient strategy for assembling collagen peptides into well-defined collagen filaments remains elusive, owing to the nonspecific intermolecular interactions in collagen triple-helix formation. Here, we develop a new strategy for designing peptides that form triple-helical collagen-mimicking filaments using a single-residue side-chain modification. By organizing the intermolecular steric interactions in a "bump-gap" design, the peptides self-assemble into interlocked, endlessly growing triple-helical filaments with exceptional specificity. The peptide filaments exhibit high aspect ratios with micrometer lengths and are capable of forming networked structures that build hydrogels. These collagen-mimicking hydrogels, triggered by pH-dependent self-assembly, demonstrate superior stiffness over natural collagen with remarkable shear-thinning properties.