Browsing by Author "Xu, ZP"

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    Layered double hydroxide nanoparticles incorporating terbium: applicability as a fluorescent probe and morphology modifier
    (Springer, 2010-01) Musumeci, AW; Xu, ZP; Smith, SV; Minchin, RF; Martin, DJ
    Stable and non-invasive fluorescent probes for nanotoxicological investigations are greatly needed to track the fate of nanoparticles in biological systems. The potential for terbium (Tb) to act as a fluorescent probe and its effect on layered double hydroxide (LDH) nanoparticle morphology are presented in this study. Incorporation of Tb during synthesis offers a simple methodology to easily tailor LDH nanoparticle thickness. A three-fold reduction in the average crystallite thickness (from 13 to 4 nm) has been achieved, whilst preferential lateral growth of LDH nanoparticles in the a-b crystal plane has been observed with increasing Tb loadings. Remarkably, Tb-LDH nanoparticles have emitted green fluorescence with a fluorescence quantum yield of 0.044. © 2010, Springer.
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    Synthesis and characterization of dual radiolabeled layered double hydroxide nanoparticles for use in in vitro and in vivo nanotoxicology studies
    (American Chemical Society, 2010-01-21) Musumeci, AW; Schiller, TL; Xu, ZP; Minchin, RF; Martin, DJ; Smith, SV
    Layered double hydroxide (LDH) nanomaterials are currently the focus of intense scientific interest due to their potential application in drug and gene delivery research. However, the emerging field of nanotoxicology requires the development of new and more sensitive methodologies to follow the in vivo delivery kinetics as well as the persistence and bioaccumulation of the LDH carriers subsequent to delivery of the payload to the target area. Radioisotopic labeling offers very high detection sensitivity (<10−14 moles) and straightforward quantitation with respect to other labeling techniques. We have shown that incorporation of naturally occurring Co2+ and Ga3+ cations into the LDH structure has a negligible effect on the physiochemical properties of the pristine nanoparticles. Radiolabeling through dual isomorphous substitution of 57Co2+ and 67Ga3+ into the LDH structure offers the utility to accurately track and also follow the structural dissolution of these nanomaterials over a range of biologically relevant pHs. Radiolabeled-LDH kinetic release profiles in conjunction with transmission electron microscopy and X-ray diffraction studies have revealed that the bulk dissolution of LDH occurs with no preferential leaching of the 57Co2+ or 67Ga3+ metal species from the crystal structure. Furthermore, the present study clearly demonstrates how radiolabeling methodologies described here may be adapted for use in other similar clay systems and allow for the first time noninvasive imaging and monitoring of the fate of nanoparticles. © 2010, American Chemical Society