Abstract: The object of this invention is an improved method for biospecific multiparameter assay method based on the use of different categories of microparticles as solid support for different bioaffinity reagents. This invention allows the use of microparticles of small size and with very moderate monodispersity and conventional short decay time fluorescent labels for labelling the biospecific reactants. The high sensitivity of this method is based on the use of confocal excitation and detection, or alternatively, two-photon excitation for measurement of the biospecific reaction. The identification of the category of the microparticle is based on the use of fluorescent or Raman scattering indicators associated with the microparticles representing different analytes.

Abstract: A method and device for determination of absolute values of the size and the refractive index of individual microparticles. An optical scanning device for measurement of angular scattering pattern from individual microparticles is described. The light scatter is measured in different angles from moving particles inside the scanning optical system and the values and the angular locations of minima and maxima of the scattering pattern are registered. The size and the refractive index of individual microparticles are calculated from the registered minima and maxima using an empirical equation. An empirical equation has been derived from statistical analysis of angular scattering patterns. These patterns have been calculated on the basis of Mie scattering theory.