pH‐Triggered Thermally Responsive Polymer Core–Shell Nanoparticles for Drug Delivery

Abstract

trate (GNO, Alfa Aesar, Ward Hill, MA) for 6 h at 16 C. The products were collected and washed by centrifugation before analysis. For reactions at low concentration, native and denatured filaments at 0.2 mg mL ±1 were incubated in 1.6 mL polyethylene centrifuge tubes with 1 mL of a 0.1 M aqueous solution of gallium nitrate for 24 h at 25 C. The products were collected and washed by centrifugation before analysis. Base-catalyzed synthesis of Ga 2 O 3 was accomplished by dissolving 1.82 g (0.005 mol) of GNO in 30 g of water contained in a glass vessel, followed by the addition of 7.24 g (0.06 mol) of concentrated (~29 wt.-%) ammonium hydroxide (NH 4 OH). Precipitated product was collected and washed by centrifugation before heat treatment. Hydrated GNO was prepared by dissolving 1.82 g (0.005 mol) of GNO in 50 g of water contained in a glass vessel. The solution was mixed for 1 h, followed by room-temperature vacuum evaporation of the water. The dried powder product was used for further heat treatments. As-received GNO powder was used directly from the container for pyrolysis experiments. Thermal treatments of base-hydrolyzed, hydrated, and as-received GNO powders were conducted by heating 50 mg of starting material in alumina crucibles placed in quartz Schlenk tubes. Heat treatments (10 C min ±1 ) were carried out in air to temperatures between 200±1000 C for 1 h.X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM): Approximately 25 mg of each heat-treated sample was ground (with a silicon-powder internal standard) to a fine powder, placed on a glass microscope slide or a single-crystal (100) silicon wafer, and characterized by X-ray diffraction (Phillips X'Pert; Amsterdam, The Netherlands) using a gonio scan (20±60, 0.02 step ±1 , 5 s step ±1 ; source slit sizes of 1/4 and 1/2, and detector slit sizes of 1/4 and 0.2 mm). Surface features of Ga 2 O 3 powders and Ga 2 O 3 -coated silicatein filaments were imaged by a cold cathode field-emission scanning electron microscope (SEM; JEOL JSM 6300F, Peabody, MA) equipped with an energy dispersive spectrometer. Specimens were mounted on conductive carbon adhesive tabs (Ted Pella, Inc., Redding, CA) and imaged (at 5 kV or 10 kV) either uncoated (for energy dispersive spectroscopy analysis) or after gold/palladium sputter coating. Energy dispersive spectroscopy (EDS, Oxford Instruments, Palo Alto, CA) was performed in conjunction with SEM to qualitatively determine chemical composition of specimens. Ga 2 O 3 -coated filaments were imaged with a transmission electron microscope (TEM, JEOL 2000FX) to observe the coating morphologies and obtain structural information via electron diffraction patterns. Lattice fringes were imaged with a high-resolution TEM (HRTEM, JEOL 2010). Both TEMs were operated at 200 kV. TEM specimens were prepared by pipetting a small amount (~20 lL) of filament suspension (in water) onto holey-carbon copper grids (Ted Pella, Inc., Redding, CA). The grids were then dried at 40 C for 5 min. Samples were ...

Folate and iron difunctionalized multiwall carbon nanotubes as dual-targeted drug nanocarrier to cancer cells

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Alginate-chitosan Coated Lecithin Core Shell Nanoparticles for Curcumin: Effect of Surface Charge on Release Properties and Biological Activities

“…Soppimath et al have synthesized polymeric core shell nanoparticles for pH responsive delivery of the drug molecules. 4 In an another study, Pacitaxel (anticancer drug) delivery was greatly enhanced when incorporated in lipid core shell nanoparticles stabilized by Pluronic F-127 polymer. 5 Lipid core shell nanoparticles were found to be effective for controlling the release of proteins like Vascular Endothelial Growth Factor (VEGF) and lysozyme.…”

Classification of stimuli–responsive polymers as anticancer drug delivery systems

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