Cyanines, also referred to as tetramethylindo(di)-carbocyanines are defined as “synthetic dyes with the general formula R2N[CH=CH]nCH=N+R2↔R2N+=CH[CH=CH]nNR2 (n is a small number) in which the nitrogen and part of the conjugated chain usually form part of a heterocyclic system, such as imidazole, pyridine, pyrrole, quinoline and thiazole.”Cyanines are used in industry biotechnology (labeling, analysis, biomedical imaging).