Backbone Engineered γ‑Peptide Amphitropic Gels for Immobilization of Semiconductor Quantum Dots and 2D Cell Culture

We
are reporting a spontaneous supramolecular assembly of backbone
engineered γ-peptide scaffold and its utility in the immobilization
of semiconductor quantum dots and in cell culture. The stimulating
feature of this γ-peptide scaffold is that it efficiently gelates
both aqueous phosphate buffers and aromatic organic solvents. A comparative
and systematic investigation reveals that the greater spontaneous
self-aggregation property of γ-peptide over the α- and
β-peptide analogues is mainly due to the backbone flexibility,
increased hydrophobicity, and π–π stacking of γ-phenylalanine
residues. The hydrogels and organogels obtained from the γ-peptide
scaffold have been characterized through field emission scanning electron
microscopy (FE-SEM), transmission electron microscopy (TEM), FT-IR,
circular dichroism (CD), wide-angle X-ray diffraction, and rheometric
study. Additionally, the peptide hydrogel has displayed a stimuli-responsive
and thixotropic signature, which leads to the injectable hydrogels.
2D cell culture studies using normal and cancer cell lines reveal
the biocompatibility of γ-peptide hydrogels. Further, the immobilization
of semiconductor core–shell quantum dots in the transparent
γ-peptide organogels showed ordered arrangement of quantum dots
along the peptide fibrillar network with retaining photophysical property.
Overall, γ-peptide scaffolds may serve as potential templates
for the design of new functional biomaterials.