Here, we are reporting for the first time a simple naphthalimide derivative that undergoes assembly in the J-type manner in the solid, solution and gel state. It shows the aggregation-induced emission property and has been used for cell imaging.
Herein we report for the
first time the supramolecular hydrogelation of a derivative of 3-nitrotyrosine
(3-NT), which is an oxidized byproduct of tyrosine, produced
in the presence of reactive nitrogen species in the cell. The 9-fluorenylmethyloxycarbonyl
(Fmoc) derivative of 3-NT, FNT, can form
self-supported hydrogels at a wide range of pH values (4.5–8.5)
in 50 mM phosphate buffer solutions. Hydrogels prepared at pH 7.0
are yellow, transparent, and thixotropic in nature. A yellow hydrogel
was obtained by changing the pH from 4.5 to 8.5. Moreover, the gelation
efficiency of the FNT gelator was enhanced by lowering
the pH of the buffer solution. pH-Dependent self-assembly properties
of the gelator were studied by using UV–vis, fluorescence,
and circular dichroism spectroscopy and wide-angle X-ray diffraction
techniques. Field-emission–scanning electron microscopy and
transmission electron microscopy studies of the self-assembled FNT hydrogel showed a nanofibrillar network structure. Interestingly,
the hydrogel showed injectable behavior at physiological pH. The low
cytotoxicity value and high antimicrobial properties of the hydrogel
indicated that it is a potential material for biomedical applications.
The self-assembly and photophysical properties of 4-nitrophenylalanine (4NP) are changed with the alteration of solvent and final self-assembly state of 4NP in competitive solvent mixture and are dictated by the solvent ratio.
Helical supramolecular architectures play important structural
and functional roles in biological systems. The helicity of synthetic
molecules can be tuned mainly by the chiral manipulation of the system.
However, tuning of helicity by the achiral unit of the molecules is
less studied. In this work, the helicity of naphthalimide-capped peptide-based
gel nanofibers is tuned by the alteration of methylene units present
in the achiral amino acid. The inversion of supramolecular helicity
has been extensively studied by CD spectroscopy and morphological
analysis. The density functional theory (DFT) study indicates that
methylene spacers influence the orientation of π–π
stacking interactions of naphthalimide units in the self-assembled
structure that regulates the helicity. This work illustrates a new
approach to tuning the supramolecular chirality of self-assembled
biomaterials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.