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Enzyme Instructed Self‐assembly of Naphthalimide‐dipeptide: Spontaneous Transformation from Nanosphere to Nanotubular Structures that Induces Hydrogelation
Author(s) -
Chakravarthy Rajan Deepan,
Mohammed Mohiuddin,
Lin HsinChieh
Publication year - 2020
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202000575
Subject(s) - dipeptide , self assembly , nanofiber , supramolecular chemistry , stacking , aqueous solution , hydrogen bond , chemistry , enzyme , materials science , peptide , nanotechnology , crystallography , organic chemistry , molecule , crystal structure , biochemistry
Understanding the structure‐morphology relationships of self‐assembled nanostructures is crucial for developing materials with the desired chemical and biological functions. Here, phosphate‐based naphthalimide (NI) derivatives have been developed for the first time to study the enzyme‐instructed self‐assembly process. Self‐assembly of simple amino acid derivative NI‐Y p resulted in non‐specific amorphous aggregates in the presence of alkaline phosphatase enzyme. On the other hand, NI‐FY p dipeptide forms spherical nanoparticles under aqueous conditions which slowly transformed into partially unzipped nanotubular structures during the enzymatic catalytic process through multiple stages which subsequently resulted in hydrogelation. The self‐assembly is driven by the formation of β‐sheet type structures stabilized by offset aromatic stacking of NI core and hydrogen bonding interactions which is confirmed with PXRD, Congo‐red staining and molecular mechanical calculations. We propose a mechanism for the self‐assembly process based on TEM and spectroscopic data. The nanotubular structures of NI‐FY p precursor exhibited higher cytotoxicity to human breast cancer cells and human cervical cancer cells when compared to the nanofiber structures of the similar Fmoc‐derivative. Overall this study provides a new understanding of the supramolecular self‐assembly of small‐molecular‐weight hydrogelators.