Patent ID: 7763439

Claim:
A separation free bioanalytical assay method for measuring an analyte from a biological fluid or suspension comprising providing a bioaffinity binding solid phase comprising a suspension of microparticles coated with a biospecific primary reagent, adding a biospecific secondary reagent labeled with a two-photon fluorescent dipyrrometheneboron difluoride dye, adding a biological fluid or suspension comprising an analyte to the suspension of microparticles, thereby forming a reaction suspension, focusing a laser into the reaction suspension to illuminate the two-photon fourescent dipyrrometheneboron difluoride dye in a focal volume, and measuring two-photon excited fluorescence from single microparticles when they randomly float or are guided by the radiation pressure of the excitation laser through the focal volume of the laser beam, wherein said two-photon fluorescent dipyrrometheneboron difluoride dye has a structure (II), wherein R 1 is substituted or unsubstituted 2-thienyl, 2-pyrrolyl, phenyl or phenylethenyl and at least one of the groups R 2 , R 3 , R 4 , R 5 , R 6 or R 7 is where X + is a cation; and the remaining groups of R 2 , R 3 , R 4 , R 5 , R 6 and R 7 are each independently of each other either hydrogen or alkyl.