Abstract: Disclosed are beads, which are chemically stable even at a normal temperature, are stable without being disintegrated even if being exposed to light, can emit a plurality of fluorescence excited by irradiating a light of single wavelength, and can be identified by a flow cytometer. A method for preparing the beads, a flow cytometer and a program for preparing the beads are also disclosed. By dyeing semiconductor nanoparticles as a fluorescent reagent to polystyrene beads, beads are identified. At the same time, semiconductor nanoparticles of a different fluorescence wavelength are also used for detection of reporter, enabling SNP specification of gene, monitoring or finding of the concentration of biopolymer such as a protein. The semiconductor nanoparticles have a feature that the fluorescence wavelength may vary by controlling the particle size and that they have a high durability compared to an ordinary fluorescent reagent since they are a semiconductor.

Abstract: Disclosed are beads, which are chemically stable even at a normal temperature, are stable without being disintegrated even if being exposed to light, can emit a plurality of fluorescence excited by irradiating a light of single wavelength, and can be identified by a flow cytometer. A method for preparing the beads, a flow cytometer and a program for preparing the beads are also disclosed. By dyeing semiconductor nanoparticles as a fluorescent reagent to polystyrene beads, beads are identified. At the same time, semiconductor nanoparticles of a different fluorescence wavelength are also used for detection of reporter, enabling SNP specification of gene, monitoring or finding of the concentration of biopolymer such as a protein. The semiconductor nanoparticles have a feature that the fluorescence wavelength may vary by controlling the particle size and that they have a high durability compared to an ordinary fluorescent reagent since they are a semiconductor.