Cyanine and related dyes, such as
merocyanine, styryl and oxonol dyes, are strongly light-absorbing and highly luminescent.
Cyanine and related dyes having functional groups make them reactive with amine, hydroxy and sulfhydryl groups are covalently attached to proteins, nucleic acids, carbohydrates, sugars, cells and combinations thereof, and other biological and nonbiological materials, to make these materials fluorescent so that they can be detected. The labeled materials can then be used in assays employing excitation light sources and
luminescence detectors. For example, fluorescent
cyanine and related dyes can be attached to amine, hydroxy or sulfhydryl groups of
avidin and to antibodies and to lectins. Thereupon,
avidin labeled with
cyanine type dyes can be used to quantify biotinylated materials and antibodies conjugated with
cyanine-type dyes can be used to detect and measure antigens and haptens. In addition, cyanine-conjugated lectins can be used to detect specific
carbohydrate groups. Also, cyanine-conjugated fragments of
DNA or
RNA can be used to identify the presence of complementary
nucleotide sequences in
DNA or
RNA.