Abstract: Highly fluorescent latex microspheres have a diameter of less than five hundred angstroms and have more than five thousand fluorescent markers per sphere. The microspheres are prepared by reacting an acrylic latex bead with a diamine and a fluorescent amine at elevated pH. A protein such as avidin or an immunoglobulin may then be conjugated to the diamine. A single fluorescent microsphere is visible using standard fluorescent microscopy. Therefore the microspheres may be utilized not only to visualize cell surface anitgens but also DNA encoding for single genes, by means of a biotinylated DNA probe.

Abstract: Highly fluorescent latex microspheres have a diameter of less than five hundred angstroms and have more than five thousand fluorescent markers per sphere. The microspheres are prepared by reacting an acrylic latex bead with a diamine and a fluorescent amine at elevated pH to attach a spacer arm and a marker, respectively, to the bead by transacylation of ester terminations on the surface of the bead. A protein such as avidin or an immunoglobulin may then be conjugated to the spacer arm. A single fluorescent microsphere is visible using standard fluorescent microscopy. Therefore the microspheres may be utilitzed not only to visualize cell surface antigens but also DNA encoding for single genes, by means of a biotinylated DNA probe.