Conjugated polymers with strong light-harvesting capability

can amplify fluorescence signal and improve the sensitivity of biological detection.New type of biosensors based on conjugated polymers system are of importance in understanding the information transfer in biological systems

especially in the early diagnosis of disease. The main-chain structures of water soluble polythiophene derivatives are easily changed in the external environment

thereby causing the changes of absorption spectra and solution colors. In recent years

visual biological detections based on water-soluble polythiophene have been widely developed. In this review

the design

synthesis of water-soluble polythiophene derivatives and their applications in visual biological detections are introduced

and finally future trends in this area are discussed.