Biosensors from conjugated polyelectrolyte complexes
n this paper, we report an investigation of the PL from a conjugated polyelectrolyte complex in aqueous solution. We show that the anionic conjugated polymer alone is subject to nonspecific effects on the PL (luminescence enhancement), which complicates the use of conjugated polyelectrolytes in biosensing applications. We find, however, that when a cationic polymer is added in the solution to associate with the anionic conjugated polyelectrolyte and form a charge neutral complex (CNC) [formed in aqueous solution by an anionic conjugated polyelectrolyte and a saturated cationic polyelectrolyte at a 1:1 ratio (per repeat unit)], the CNC shows little evidence of nonspecific interactions with biopolymers that occur with the anionic conjugated polymer alone. Moreover, we demonstrate that PL from the CNC can be quenched by both cationic and anionic quenchers. We also demonstrate full PL recovery on the specific recognition between negatively charged dinitrophenol (DNP) derivative, (DNP-BS−) and anti-DNP IgG, indicating a conjugated polymer-based biosensor with moderate sensitivity and rapid response.