Quantum dots-based fluorescent probes for turn-on and turn-off sensing of butyrylcholinesterase.

A novel turn-on and turn-off sensor based on the fluorescence change of quantum dots (QDs) has been developed to detect the activity of butyrylcholinesterase (BChE). In the turn-on sensing system, we realized the detection of BChE with just one enzyme. A linear calibration plot of the activity of BChE was obtained in the wide amounts range from 10 to 1000 U/L and the detection limit was 10 U/L. In the turn-off sensing system, we realized the sensing of BChE with a wide linear relationship of 10-2000 U/L which was much wider than many other detection methods. We also studied the application in serum sample detection. The BChE sensor shows great performances. Furthermore, the turn-on and turn-off sensing mechanisms were studied extensively. These results showed that our strategy would most probably be applicable in assembling diagnostic micro-device for realizing the rapid clinical analysis of BChE.