Peptide 1 with an Aβ42 amyloid nucleating core demonstrates step-wise self-assembly in water. Variation of temperature or solvent composition arrests the self-assembly to give metastable nanoparticles, which undergo self-assembly on gradual increase in temperature and eventually produce kinetically controlled nanofibers and thermodynamically stable twisted helical bundles. Mechanical agitation of the fibers provided access to short seeds with narrow polydispersity index, which by mediation of seeded supramolecular polymerization establishes perfect control over the length of the nanofibers. Such pathway dependence and the length control of the supramolecular peptide nanofibers is exploited to tune the mechanical strength of the resulting hydrogel materials.

The present study reports the development of a unique class of Cytochrome C (CytC)-loaded cross-beta amyloid nanohybrids. The peroxidase activity of the bound CytC increased up to two orders of magnitude in organic solvents compared to the activity of unbound CytC in water. The amyloid sequences used in the study feature the nucleating core (17) LVFF(21) of the beta amyloid (Aβ), which assembled to form homogenous fibers and nanotubes. The morphology and exposed surface of the amyloid nanohydrids critically modulated the CytC activity. A CytC-Ac-KLVFFAE-NH2 hybrid featuring nanofiber morphology showed 308-fold higher activity than unbound CytC in water, which increased to 450-fold with the nanotube morphology of CytC-Ac-KLVFFAL-NH2 . Notably, activity declined substantially when the exposed surface charge was detuned by replacing lysine with histidine, thus underpinning the importance of surface charge. This enzyme-amyloid nanohybrid system could facilitate the technological application of enzymes.

Enzymes are the most efficient catalysts in nature that possess an impressive range of catalytic activities albeit limited by the stability in adverse condition. Functional peptides have emerged as alternative...

Herein, we report the efficient exfoliation of MoS2 in aqueous medium by short cationic peptide nanotubes featuring the nucleating core (17) LVFFA(21) of β-amyloid (Aβ 1-42), a sequence associated with Alzheimer's disease. The role of morphology, length, and nature of the amyloid surface on exfoliation/dispersions of MoS2 were investigated through specific mutations of the amyloid sequences. Notably, owing to the properties of both the constituents, self-assembled soft nanostructures and MoS2 , the hybrid dispersions responded reversibly to various stimuli, including temperature, pH, and light. Addition of a protease resulted in loss of the dispersions, which are otherwise stable for months at ambient conditions. The design flexibility of the peptide sequences, along with the stimuli-responsiveness and biodegradability, can complement the applications of MoS2 in diverse fields.

Peptide hydrogels have recently emerged as potential biomaterials for designing synthetic scaffolds in tissue engineering. We demonstrate pathway-controlled self-assembly of peptide amphiphile 1 to furnish kinetically controlled nanofibers (1 NF ) and thermodynamically stable twisted helical bundles (1 TB ). These supramolecular nanostructures with varied persistence lengths promote in situ mineralization to yield templated bioactive glass composites, 1 NF BG and 1 TB BG − resorbable, mesoporous, and degradable biomaterials as bone scaffolds. The structural features of the hydrogel composites are investigated extensively with microscopic characterization, energydispersive X-ray spectroscopy, Raman spectroscopy, and XPS to conclude 1 TB BG as the superior material with higher percentage of open network structures as obtained from ratios of nonbridging and bridging oxygen. The hydrogel composites show excellent dynamic and self-healing behavior from rheological studies, especially the elastic modulus of 1 TB BG being almost comparable to natural bone. Upon incubation in simulated body fluid, the bioglass composites illustrate tunable bioactive response mediated by the structural and topological control to induce the deposition of multiphasic calcium phosphate along with octacalcium phosphate and carbonate hydroxyapatite. Finally, such spatiotemporal composites facilitate stiffness-controlled osteoblast cellular interactions to support U2OS subsistence in the hydrogel matrix, highlighting their potential as a substrate for osteoblast growth for prolonged culture periods and in 3D bone tissue modeling.