Morphology\nTransition of Tripeptides from Porous Spherical\nto Rod-like Nanostructures for Small-Molecule Adsorption

Peptides possess a remarkable propensity to adopt distinct\nmorphologies,\nranging from simple aggregates to complex structures such as fibrils\nand nanotubes. Morphology transformation in peptides is intricately\nlinked to the physicochemical properties of peptides and external\nfactors such as pH, temperature, and solvent conditions. Thus, it\nis more complex. Herein, we present four tripeptides, Boc-LVL-OMe\n(LVL), Boc-IVI-OMe (IVI), Boc-LVI-OMe (LVI), and Boc-IVL-OMe (IVL),\nwhich undergo direct morphological transformation (except for Boc-IVL-OMe)\nwith time. The morphological transformation from nanospheres to rod-like\nstructures was verified using electron microscopic studies (FESEM\nand FETEM). Dynamic light scattering (DLS) studies further supported\nthe results and are in good agreement with the observed phenomena.\nCD and FTIR studies were conducted for conformational analysis, suggesting\na mixture of unordered and β-sheet conformations. Except for\nIVL, all other tripeptides are mesoporous and adsorb N<sub>2</sub> gas. Another important application of our designed tripeptides is\nthat they can encapsulate the low-molecular-weight biologically active\ndrug molecule curcumin. The encapsulation property and its sustained\nrelease after being treated with salt were studied by using fluorescence\nspectroscopy and fluorescence microscopy. Therefore, understanding\nthe dynamics of these interactions and their impact on peptide morphology\nis crucial for harnessing their functional diversity in applications,\nsuch as drug delivery, tissue engineering, and nanotechnology.