pH-Operated Mechanized Porous Silicon Nanoparticles

Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA.
Journal of the American Chemical Society (Impact Factor: 12.11). 06/2011; 133(23):8798-801. DOI: 10.1021/ja201252e
Source: PubMed

ABSTRACT Porous silicon nanoparticles (PSiNPs) were synthesized by silver-assisted electroless chemical etching of silicon nanowires generated on a silicon wafer. The rod-shaped particles (200-400 nm long and 100-200 nm in diameter) were derivatized with a cyclodextrin-based nanovalve that was closed at the physiological pH of 7.4 but open at pH <6. Release profiles in water and tissue culture media showed that no cargo leaked when the valves were closed and that release occurred immediately after acidification. In vitro studies using human pancreatic carcinoma PANC-1 cells proved that these PSiNPs were endocytosed and carried cargo molecules into the cells and released them in response to lysosomal acidity. These studies show that PSiNPs can serve as an autonomously functioning delivery platform in biological systems and open new possibilities for drug delivery.

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Available from: Jeffrey I Zink, Sep 27, 2015
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    • "Several MSNs-based controlled release systems have been developed by the application of different kinds of pore blockers, including inorganic nanoparticles (Muhammad et al., 2011), organic molecules (Mahkam et al., 2012), polymer (Colilla et al., 2013) and supramolecular assemblies (Xue et al., 2011). Various physical/chemical stimuli, such as photo, pH, temperature and enzymes, have been used as actuators for uncapping the gatekeepers and releasing entrapped guest molecules (Xue et al., 2011). As the Address for correspondence: M. Mahkam, Chemistry Department, "
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    ABSTRACT: Abstract The objective of this study was to develop pH-responsive silica nanoparticles by imidazole-based ionic liquid for controlled release of methotrexate. In this article, we synthesized pH-responsive 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 (1)HNMR 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.
    Drug Delivery 10/2013; 21(3). DOI:10.3109/10717544.2013.838714 · 2.56 Impact Factor
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    • "Author's personal copy 2. Preparation of pSi Carrier Particles 2.1. Fabrication pSi is generally produced by electrochemical etching, which uses hydrofluoric acid and strong electrical currents to etch pores of defined sizes into silicon substrates (Chiappini et al., 2010; Xue et al., 2011). Particles are created by lithography of the pSi. "
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