Sonochemical Formation of Copper/Iron-Modified Graphene Oxide Nanocomposites for Ketorolac Delivery.

A feasible sonochemical approach is described for the preparation of copper/iron-modified graphene oxide nanocomposites through ultrasonication (20 kHz, 18 W cm-2 ) of an aqueous solution containing copper and iron ion precursors. Unique copper-, copper/iron- and iron-modified graphene oxide nanocomposites have a submicron size that is smaller than that of pristine GO and a higher surface area enriched with Cu2 O, CuO, and Fe2 O3 of multiform phases (α-, ß-, ϵ-, or γ), FeO(OH), and sulfur- or carbon-containing compounds. These nanocomposites are sonochemically intercalated with the nonsteroidal anti-inflammatory drug ketorolac, which results in the formation of nanoscale carriers. Ketorolac monotonically disintegrates from these nanoscale carriers in aqueous solution upon adjustment of the pH from 1 to 8. The disintegration of ketorolac proceeds at a slower rate from the copper/iron-modified graphene oxide at increased pH, but at a faster rate from the iron-modified graphene oxide under acidic conditions.

Sonochemically Assembled Photoluminescent Copper-Modified Graphene Oxide Microspheres.

A new accessible sonochemical assembly method is developed for the preparation of photoluminescent oil-filled silica@CuS/Cu2O/CuO-graphene oxide (GO) microspheres that emit light of green, yellow, and red colors. This method is based on the ultrasonic emulsification of a biphasic mixture consisting of CuS/Cu2O/CuO-graphene oxide (GO) nanocomposites with poly(vinyl alcohol) (PVA) (aqueous phase) and tetraethyl orthosilicate with sunflower oil (organic phase). CuS/Cu2O/CuO-GO nanocomposites are composed of sonochemically formed three phases of copper: covellite CuS (p-type semiconductor), cuprite Cu2O (Bloch p-type semiconductor), and CuO (charge-transfer insulator). The photoluminescence properties of microspheres result from H-bridging between PVA and CuS/Cu2O/CuO-GO nanostructures, light absorption ability of Cu2O, and charge-transfer insulation by CuO. Substitution of PVA by S-containing methylene blue quenches fluorescence by enhanced dye adsorption on CuS/Cu2O/CuO-GO because of CuS and induced charge transfer. Non-S-containing malachite green is in a nonionized form and tends to be in the oil phase, prohibiting the charge transfer on CuS/Cu2O/CuO-GO.