No abstract

No abstract

A novel method for modifying the surface of magnetic‐resonance‐contrasting layered gadolinium hydroxide (LGdH) is developed providing them with water‐ and bio‐compatibility and acid‐resistance, all of which are essential for medical applications. A stable colloid of exfoliated layers is synthesized by exchanging interlayer anions of LGdH with oleate ions. The delaminated layers are successively coated with phospholipids with poly(ethylene glycol) tail groups, and their effectiveness as a contrast agent for magnetic resonance imaging (MRI) is demonstrated. The adaptability of this surface modification approach for incorporating functional molecules and fabricating a fluorescent colloid of LGdH, which has the potential utility as a multimodal probe, is also demonstrated. This result provides a novel approach for expanding the applications of layered inorganic materials and developing a new class of MRI contrast agents.

Colloidal solutions of layered rare-earth hydroxide nanosheets provide a simple route to deposit ultra thin luminescence fi lms. The antirefl ection and antifogging properties were integrated into transparent luminescent fi lms by the layer-by-layer assembly of Eu 3 + , Tb 3 + , Dy 3 + doped-hydroxocation nanosheets and negatively-charged SiO 2 nanoparticles. Resulting multifunctional fi lms exhibited effi cient red, green, and blue emissions with controllable intensity. Highly improved transmittance enabled us to display combinatorial color luminescence, which can be achieved by multiply overlapping individual fi lms with different combinations, without signifi cant loss of transparency. Triple overlap of red/green/blue fi lms generated an excellent white-light under 254 nm UV irradiation.

A layered gadolinium hydroxychloride (LGdH), [Gd2(OH)5(H2O)x]Cl, was synthesized from an aqueous solution of GdCl3.6H2O. The X-ray diffraction (XRD) and the selected area electron diffraction (SAED) studies showed that this compound crystallizes in the orthorhombic structure (a = 12.88(4) A, b = 7.30(2) A, and c = 8.46(3) A) which is isostructural with [Eu2(OH)5(H2O)x]Cl. Interestingly, this layered material was readily dispersed and led to a stable colloidal nanosheet in aqueous medium. The obtained colloidal solutions were characterized by the evaluation of their stability in acidic solution, their in vitro cytotoxicity, and their magnetic resonance imaging (MRI) relaxation properties. It is reported that the relaxometry analysis of LGdH suspensions exhibits a sufficient contrast effect for T1 weighted magnetic resonance imaging.