Microemulsion-Made Gadolinium Carbonate Hollow Nanospheres Showing Magnetothermal Heating And Drug Release

Gadolinium carbonate (Gd-2(CO3)(3)) hollow nanospheres and their suitability for drug transport and magnetothermally-induced drug release are presented. The hollow nanospheres are prepared via a microemulsion-based synthesis using tris(tetramethylcyclopentadienyl) gadolinium(III) and CO2 as the starting materials. Size, structure and composition of the as-prepared Gd-2(CO3)(3) hollow nanospheres are comprehensively validated by several independent analytical methods (HRTEM, HAADF-STEM, DLS, EDXS, XRD, FT-IR, DTA-TG). Accordingly, they exhibit an outer diameter of 26 +/- 4 nm, an inner cavity of 7 +/- 2 nm, and a wall thickness of 9 +/- 3 nm. As a conceptual study, the nanocontainer-functionality of the Gd2(CO3) 3 hollow nanospheres is validated upon filling with the anti-cancerogenic agent doxorubicin (DOX), which is straightforward via the microemulsion (ME) strategy. The resulting DOX@Gd-2(CO3)(3) nano-containers provide the option of multimodal imaging including optical and magnetic resonance imaging (OI, MRI) as well as magnetothermal heating and drug release. As a proof-of-concept, we could already prove the intrinsic DOX-based fluorescence, a low systemic toxicity according to in vitro studies as well as the magnetothermal effect and a magnetothermally-induced DOX release. In particular, the latter is new for Gd-containing nanoparticles and highly promising in view of theranostic nanocontainers and synergistic physical and chemical tumor treatment.