Single-Micelle-Templated Synthesis of Hollow Barium Carbonate Nanoparticle for Drug Delivery.

A laboratory-synthesized triblock copolymer poly(ethylene oxide- b -acrylic acid- b -styrene) (PEG-PAA-PS) was used as a template to synthesize hollow BaCO 3 nanoparticles (BC-NPs). The triblock copolymer was synthesized using reversible addition-fragmentation chain transfer radical polymerization. The triblock copolymer has a molecular weight of 1.88 × 10 4 g/mol. Transmission electron microscopy measurements confirm the formation of spherical micelles with a PEG corona, PAA shell, and PS core in an aqueous solution. Furthermore, the dynamic light scattering experiment revealed the electrostatic interaction of Ba 2+ ions with an anionic poly(acrylic acid) block of the micelles. The controlled precipitation of BaCO 3 around spherical polymeric micelles followed by calcination allows for the synthesis of hollow BC-NPs with cavity diameters of 15 nm and a shell thickness of 5 nm. The encapsulation and release of methotrexate from hollow BC-NPs at pH 7.4 was studied. The cell viability experiments indicate the possibility of BC-NPs maintaining biocompatibility for a prolonged time.