A novel optical nanoprobe for trypsin detection and inhibitor screening based on Mn-doped ZnSe quantum dots

► A new fluorescence turn-on nanoprobe for detection of trypsin was reported. ► The method was based on the fluorescence quenching and recovery of Mn:ZnSe d-dots. ► Good sensitivity and selectivity were obtained for the determination of trypsin. ► Trypsin in human biological fluids was detected with satisfactory results.