Abstract

A bead construct includes a bead, a fluorophore molecule, first and second linker molecules and a ligand molecule. The fluorophore molecule comprises at least two subunits connected to each other by at least one internal linker that provides conformational freedom to the at least two subunits. An optical signal emitted by the fluorophore molecule changes when reducing the conformational freedom of the at least two subunits to each other. The first linker molecule is connected to the bead and to one of the subunits of the flurophore molecule. The second linker molecule is connected to another one of the subunits of the fluorophore molecule. The ligand molecule is connected to the second linker molecule.