Abstract: A novel form of dendrimer, polybranched molecule, is described in which fluorescent dyes of the structure exist in a micro environment that affects their fluorescent properties. Within the dendrimer, poly-branched molecules are cleavage sites. When these cleavage sites are treated with a suitable chemical or enzyme which cleaves selective bonds the dyes of the structure are released and a change in their optical properties is effected, notably an increase in fluorescent signal. Methods of using the dendrimer, poly-branched molecule in assays of biological molecules are also described.