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Of the methods employed in the preparation of one-dimensional lanthanide phosphate (LnPO 4) nanorods/nanowires, such as GdPO 4, the hydrothermal method has been mainly used as a synthetic route. In this study, we report a facile low-temperature solution approach to prepare GdPO 4·H 2O nanorods by simply refluxing GdCl 3and KH 2PO 4for only 15 minat 88 °C, an approach that can easily be scaled up by increasing the reagent amounts. We observed a highly viscous macroscopic hydrogel-like material when we mixed as-prepared GdPO 4·H 2O nanomaterials with H 2O. Hydrogels are an important class of biomaterials. Their building blocks, normally formed from protein-, peptide-, polymer-, and lipid-based materials, offer three-dimensional scaffolds for drug delivery, tissue engineering, and biosensors. Our preliminary results showed that GdPO 4·H 2O hydrogels could be used for encapsulation and drug release, and that they were biocompatible, acting as scaffolds to foster cell proliferation. These findings suggested that they might have biomedical uses. Our findings may lead to the creation of other inorganic nanomaterial-based hydrogels apart from the organic and biomolecular protein-, peptide-, polymer-, and lipid-based building blocks. [ABSTRACT FROM AUTHOR]

Nanocontrast agents have great potential in magnetic resonance (MR) molecular imaging applications for clinical diagnosis. We synthesized Au3Cu1 (gold and copper) nanoshells that showed a promising MR contrast effect. For in vitro MR images, the large proton r1 relaxivities brightened T1-weighted images. As for the proton-dephasing effect in T2, Au3Cu1 lightened MR images at the low concentration of 0.125 mg mL-1 (3.84 × 10-7 mM), and then the signal continuously decreased as the concentration increased. For in vivo MR imaging, Au3Cu1 nanocontrast agents enhanced the contrast of blood vessels and suggested their potential use in MR angiography as blood-pool agents. We propose that (1) the cooperativity originating from the form of the nanoparticles and (2) the large surface area coordinated to water from their porous hollow morphology are important for efficient relaxivity. In a cytotoxicity and animal survival assay, Au3Cu1 nanocontrast agents showed a dose-dependent toxic effect: the viability rate of experimental mice reached 83% at a dose of 20 mg kg-1 and as much as 100% at 2 mg kg-1. [ABSTRACT FROM AUTHOR]