Visual sensing with conjugated polyelectrolytes

The recent development in chemo- and biosensors has witnessed improved sensitivity and selectivity with innovative techniques. The ability to achieve real-time detection with easy-to-operate procedures is highly sought after and will continue to gain importance. Conjugated polyelectrolytes (CPEs), having demonstrated their effectiveness in sensing of a myriad of targets, not only provide versatile sensing channels, but also enable unaided-eye detection. In this review, examples of visual sensing using CPEs are highlighted for the detection of targets ranging from biomacromolecules to small chemical species. Based on the types of transduction mechanisms, they are presented in two sections, namely colorimetric sensing and fluorometric sensing, categorized within each according to the types of target molecules. We envisage that further development of functionalized CPEs will afford an advanced tool for clinical diagnosis, food inspection and environment monitoring.