Abstract: The present invention concerns a luminescent particle comprising a nanoparticle of formula A1-xLnxVO4(1-y)(PO4)y??(I) in which A is selected from yttrium (Y), gadolinium (Gd), lanthanum (La), and mixtures thereof; Ln is selected from europium (Eu), dysprosium (Dy), samarium (Sm), neodymium (Nd), erbium (Er), ytterbium (Yb), and mixtures thereof; 0<x<1; and 0?y<1; characterized in that the nanoparticle on its surface has tetraalkylammonium cations in an amount such that said nanoparticle has a zeta potential, ?, of less than or equal to ?28 mV in an aqueous medium with a pH?5, more particularly with a pH?5.5, and with an ionic conductivity >100 ?S·cm?1. It also concerns a method for preparing such luminescent particles, a colloidal suspension of these particles, and the use thereof as a diagnostic agent, and also a diagnostic kit comprising such luminescent particles.

Abstract: The present invention relates to an in vitro method for detecting and/or quantifying a biological or chemical substance of interest in a liquid sample, by a capillary action test using, as probes, photoluminescent inorganic nanoparticles, of formula A1-xLnxVO4(1-y)(PO4)y (II), in which Ln is selected from europium (Eu), dysprosium (Dy), samarium (Sm), neodymium (Nd), erbium (Er), ytterbium (Yb), thulium (Tm), praseodymium (Pr), holmium (Ho) and mixtures thereof; A is selected from yttrium (Y), gadolinium (Gd), lanthanum (La), lutetium (Lu), and mixtures thereof; 0<x<1; and 0?y<1, said method employing detection of the luminescence, with an emission lifetime shorter than 100 ms, of the nanoparticles, after one-photon absorption, by excitation of the matrix at a wavelength less than or equal to 320 nm. It also relates to a capillary action test device comprising, as probes, the aforementioned nanoparticles, as well as the use of such a method for purposes of in vitro diagnostics.

Abstract: A method which can be used to analyse oxidising species in a sample, including: placing the sample in contact with a first photoluminescent agent, and a second optically active agent, at least the first photoluminescent agent including nanoparticles doped with rare earth elements and being oxidisable, the luminescence of the first photoluminescent agent varying, at least at one first wavelength, with the amount of oxidising species, and the signal emitted by the second optically active agent being constant or varying, at least at one second wavelength other than the first wavelength, with the amount of oxidising species in a direction opposite to the luminescence of the first photoluminescent agent; energising the first and second agents in the sample; measuring the light intensity of the sample at least at the first and second wavelengths; and assessing the presence and/or the amount of oxidising species by interpreting the measured light intensities.

Abstract: A process for ultrasensitive in vitro detection and/or quantification of a substance of interest in a sample is performed by detecting the luminescence emission by photoluminescent inorganic nanoparticles. The process includes (i) use of photoluminescent particles comprising a photoluminescent inorganic nanoparticle consisting of a crystalline matrix having at least 103 rare-earth ions, and coupled to a targeting agent for the substance to be analyzed, under conditions conducive to their association with the sample substance to be analyzed; (ii) exciting the rare-earth ions of the particles by an illumination device having a power of at least 50 mW and an excitation intensity of at least 1 W/cm2; (iii) detecting the luminescence emission by the particles after single-photon absorption; and (iv) determining the presence and/or concentration of the substance by interpreting said luminescence measurement. This process can be used for in vitro diagnostic purposes and as an in vitro diagnostic kit.

Abstract: The present invention concerns a luminescent particle comprising a nanoparticle of formula A1?xLnxVO4(1?y)(PO4)y ??(I) in which A is selected from yttrium (Y), gadolinium (Gd), lanthanum (La), and mixtures thereof; Ln is selected from europium (Eu), dysprosium (Dy), samarium (Sm), neodymium (Nd), erbium (Er), ytterbium (Yb), and mixtures thereof; 0<x<1; and 0<y<1; characterized in that the nanoparticle on its surface has tetraalkylammonium cations in an amount such that said nanoparticle has a zeta potential, ?, of less than or equal to ?28 mV in an aqueous medium with a pH?5, more particularly with a pH?5.5, and with an ionic conductivity >100 ?S.cm?1. It also concerns a method for preparing such luminescent particles, a colloidal suspension of these particles, and the use thereof as a diagnostic agent, and also a diagnostic kit comprising such luminescent particles.

Abstract: The invention relates to a method which can be used to analyse oxidising species in a sample, comprising the steps which consist of: placing (12) the sample in contact with a first photoluminescent agent, and a second optically active agent, at least the first photoluminescent agent including nanoparticles doped with rare earth elements and being oxidisable, the luminescence of the first photoluminescent agent varying, at least at one first wavelength, with the amount of oxidising species, and the signal emitted by the second optically active agent being constant or varying, at least at one second wavelength other than the first wavelength, with the amount of oxidising species in a direction opposite to the luminescence of the first photoluminescent agent; energising (16) the first and second agents in the sample; measuring (18) the light intensity of the sample at least at said first and second wavelengths; and assessing the presence and/or the amount of oxidising species by interpreting (20) said measured l

Abstract: The present application concerns multimodal composite products for imaging, in particular for diagnostic imaging, and optionally for therapy, in particular composite products which are capable of being used as contrast agents, in particular in magnetic resonance imaging (MRI), and/or in imaging techniques such as, for example, in optical imaging, in the optical detection of oxidants, in positron emission tomography (PET), in tomodensitometry (TDM) and/or in ultrasound imaging, and optionally simultaneously for use in therapy. These products are based on a particle comprising or consisting of a portion provided with a contrast agent activity and/or a paramagnetic activity, and a portion provided with a luminescent activity and optionally an oxidant detection activity.

Abstract: The present application concerns multimodal composite products for imaging, in particular for diagnostic imaging, and optionally for therapy, in particular composite products which are capable of being used as contrast agents, in particular in magnetic resonance imaging (MRI), and/or in imaging techniques such as, for example, in optical imaging, in the optical detection of oxidants, in positron emission tomography (PET), in tomodensitometry (TDM) and/or in ultrasound imaging, and optionally simultaneously for use in therapy. These products are based on a particle comprising or consisting of a portion provided with a contrast agent activity and/or a paramagnetic activity, and a portion provided with a luminescent activity and optionally an oxidant detection activity.