Silica particles as luminescent markers alternative to the tandem-dyes

The method allows to obtain directly and immediately luminescent systems alternative to the classic DYES TANDEM-based fluorophore-conjugated or phycoerythrin fluorophore-alloficocianina, and also nanostructured systems such as Quantum Dots (QDs).

Title of the patent Silica nanoparticles doped with multiple dyes featuring highly efficient energy transfer and tunable stokes-shift
Thematic area Chemistry and biotechnology
Ownership Alma Mater Studiorum - Università di Bologna
Inventors Luca Prodi, Sara Bonacchi, Marco Montalti, Nelsi Zaccheroni, Riccardo Juris, Damiano Genovese, Enrico Rampazzo
Protection Europe, USA, Japan, China
Licensing status Available for licensing agreement
Keywords Nanoparticles, TANDEM DYES, FRET, phycoerythrin (PE), allophycocyanin (APC), cytometry, fluorocytometry, nanospheres, silica, pluronic F127, luminescent, fluorescence, electrochemiluminescence, probe, biotin, core-shell, labelling
Filed on Oct 14, 2010

The dyes are used as luminescent markers in different applications. The fluorescence measurements are generally very sensitive, low cost, easy to perform and very versatile, and offer a spatial resolution sub micrometer and a lower time to milliseconds. The versatility of luminescence spectroscopy also stems from the large number of parameters that can be varied to optimize the signal. Particularly complex analytical problems can be overcome by controlling the wavelengths of excitation and emission, the acquisition time window signal and the polarization of the excitation light and / or emitted.

Using some silica particles in combination with a selection of dyes provided with particular spectral characteristics, it is possible to obtain systems with high Stokes shift, even using a single wavelength of excitation and in which the problem of the car off of the dyes is avoided or substantially reduced. At the same time you get a dye which has a fluorescence emission at a longer wavelength, although the excitation is made at a shorter wavelength. The object of the present invention is thus a silica particle comprising a micelle having a substantially hydrophilic outer shell and a central part substantially hydrophobic; a core, which is located in the central portion of the micelle and includes a lattice of silicate; a plurality of molecules, which comprises at least one surfactant molecule functionalized.

The method is proposed as suitable to develop luminescent markers in which there is a high separation between the wavelength of excitation and the emission. Among the immediate applications there are those related to flow cytometry. In addition to these advantages, we can mention:

  • Sensitization very high and very low residual emission of the acceptor end of the different donors, when the particle contains more than two dyes; 
  • Very large Stokes shifts, up to 700-800 nm; 
  • Very high brightness, even exciting the donor at higher energy (largest donor in blue); 
  • Residual intensity altogether negligible for all dyes, except for the last acceptor.