Water-soluble conjugated polymers as the platform for protein sensors

The booming development of protein detection requires simple, sensitive, and reliable biosensor systems. Water-soluble conjugated polymers have been widely used for protein sensing due to their distinct optical response in the presence of different analytes. This review summarizes the recent developments in water-soluble conjugated polymer-based protein sensors. Based on the different optical responses of conjugated polymers to proteins, these assays are categorized into three groups. The conformational change of cationic poly(thiophene)s is used to generate unique colorimetric or fluorescent transduction upon interaction with target proteins. Super-quenching of water-soluble poly(phenylene vinylene)s and poly(phenylene ethynylene)s has been developed into fluorescence turn-on and turn-off protein assays. Energy transfer between poly(fluorene-co-phenylene) derivatives and acceptor dyes is also utilized to develop fluorescence turn-on protein assays with amplified signal output. The fine-tuning of conjugated polymer structures will benefit the design of versatile optical probes to satisfy the sophisticated requirements for protein sensors.