Keywords
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Biocompatibility, cationic nanocomposite,
controlled drug release, mesoporous silica,
methotrexate, nanovalve, pH responsive
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Abstract
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The objective of this study was to develop pH-responsive silica nanoparticles by imidazolebased
ionic liquid for controlled release of methotrexate. In this article, we synthesized pHresponsive
cationic silica nanoparticles by graft copolymerization of vinyl functionalized silica
nanoparticles and methacrylic acid (MAA) monomer. Imidazole-based ionic liquid (Im-IL) was
verified by 1HNMR and Fourier-transform infrared (FTIR) spectroscopy. The synthesized
functionalized silica particles were characterized and confirmed by various technologies
including the scanning electron microscopy (SEM), the infrared spectroscopy (IR) and the
thermogravimetric analysis (TGA). SEM results reveal the uniformity in size/shape of silica
particles. This nanosystem is modified for targeted delivery of an anticancer agent methotrexate.
The nanocomposite-MTX complex was formed at physiological pH (7.4) due to the
electrostatic interactions between anionic carboxylic group of MTX molecules and cationic
rings in carrier, while, the release of which can be achieved through the cleavage of the
nanocomposite-MTX complex by protonation of carboxyl groups in the MTX segment that are
sensitive to variations in external pH at weak acidic conditions. FT-IR spectroscopy showed the
presence of light interactions between the silicate silanols and the drug. MCF7 cells were
incubated with the MTX-free nanocomposite and MTX-loaded nanocomposite at various
concentrations for 24, 48 and 72 h, and the data showed that the nanocomposites themselves
did not affect the growth of MCF7 cells. Antitumor activity of the MTX-loaded nanocomposites
against the cells was kept over the whole experiment process. The results showed that the MTX
could be released from the fibers without losing cytotoxicity.
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