Yan et al (2013) reported a target-responsive “sweet” hydrogel combined with a commercial glucose meter for cocaine and adenosine triphosphate detection. Su et al.(2013) established a sensitive copper(II) sensor which combined the merits of PGM and click chemistry. We also devel- oped a convenient histidine sensor based on the strategy of click chemistry by using PGM as readout
However, it can only detect a single target, blood glucose.