A new type of portable pohotoelectrochemical sensor with polarity-switchable photocurrent for dopamine detection

The construction of accurate sensing method for dopamine (DA) is significant for the early diagnosis of some neurological diseases. Previous studies show that the concentration of DA in human body ranges from a few pM to several mM, depending on the sample species. Herein, a portable and sensitive photoelectrochemical (PEC) sensor for DA detection has been constructed, which is homogeneously deposited by thiophene-doped graphitic carbon nitride on the films of single-walled carbon nanotubes via vacuum filtration. In contrast to other PEC sensors for DA detections, our sensor shows polarity-switchable photocurrent with increasing DA concentration. Based on the polarity-switchable current response, the proposed PEC sensor exhibits good selectivity and a relatively wide detection range of 2.5–50 μM with the detection limit of 0.36 μM for DA. Furthermore, the applicability of the sensor was also tested for biological samples. The proposed PEC sensor holds much better potential applications in on-site disease monitoring.