Water-Soluble Polymeric Dyes Having Pendant Chromophores

A polymeric tandem dye comprising a segment of formula (IIa):

• wherein:
• the polymeric backbone of non-conjugated units comprises SM1, SM2 and SM3 co-monomers that are each independently a non-conjugated co-monomer;
• each D1 is independently a pendant donor chromophore linked to SM1;
• each A1 is independently an acceptor fluorophore linked to SM2;
• each Z2 is an optional sidechain group linked to SM3;
• x is 50 mol % or more;
• and
• y+z is 50 mol % or less.

A method of evaluating a sample for the presence of a target analyte, the method comprising:

• (a) contacting the sample with a labelled specific binding member that specifically binds the target analyte to produce a labelled composition contacted sample, wherein the labelled specific binding member comprises:
• (i) a polymeric tandem dye comprising a polypeptide backbone, a plurality of pendant donor chromophores and an acceptor chromophore each independently linked to an amino acid residue of the polypeptide backbone and configured to provide for efficient energy transfer between the pendant donor chromophores;
• and
• (ii) a specific binding member linked to the polymeric tandem dye;
• comprising a polypeptide backbone and a plurality of pendant donor chromophores each independently linked to an amino acid residue of the polypeptide backbone;
• and
• (b) assaying the labelled composition contacted sample for the presence of a labelled specific binding member-target analyte binding complex to evaluate whether the target analyte is present in the sample.