科研之友
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摘要
A new sensor format was proposed here by integrating conjugation of analyte-recognition sites and quenching the luminescence of quantum dots (QDs) in one pot during the synthesis of QDs, with protease as the model analyte. Inherently phosphorescence-attenuated Mn-doped ZnS QDs were prepared with electron transfer protein cytochrome C (Cyt C) as the ligand, which was capable of protease sensing in both label-free and activable format. This detection strategy eliminates the postsynthetic protein conjugation and responses to analyte in the turn-on mode, lowering the signal background. In the presence of protease, the initially "locked" phosphorescence of Mn-doped ZnS QDs could be activated, due to the enzymatic digestion of surface Cyt C ligand and removal of the electron-transfer quenching unit away from the close-proximity of QDs. The proposed probe exhibited good selectivity toward proteases over other proteins and enzymes. Besides, it was also capable of differentiating active and inactive serine proteases. Analytical performance of this probe was evaluated using trypsin as the model serine protease. Limits of detection (LOD) of 2 nM was obtained, which is well below the average urine trypsin level of patients. The analytical application of this probe was demonstrated in determination of trypsin in human pancreatic carcinoma (PANC-1 and 818.4) cells lysates, demonstrating the potential usefulness of this probe in future clinical diagnosis.
- 出版日期2014-10-21
- 单位四川大学
