Reagents for directed biomarker signal amplification

A complex comprising:

• (a) a conjugated polymer comprising π-conjugated repeat units, wherein the π-conjugated repeat units comprise:
• a non-ionic Ar polycyclic repeat unit that is evenly or randomly distributed along the polymer main chain;
• an MU polymer modifying unit that is evenly or randomly distributed along the polymer main chain;
• and
• a linker L1 that is an aryl or a heteroaryl group evenly or randomly distributed along the polymer main chain;
• and
• G1 and G2 terminating groups, wherein at least one of G1 and G2 is aryl or substituted aryl and G1 and G2 are different from Ar, MU and L1;
• and
• (b) a sensor biomolecule.