Monodispersed nanoparticles of conjugated polyelectrolyte brush with high charge density for rapid, specific and label-free detection of tumor marker.

Highly charged nanoparticles of a conjugated polyelectrolyte brush were used to sense the human α-fetoprotein (AFP) by observing selective superquenching in several minutes. The unique property of nanoparticles that the self-aggregation causes an unchanged or enhanced fluorescence can reduce the interference from non-target substance significantly.