title: Analyte-activable probe for protease based on cytochrome C-capped Mn: ZnS quantum dots.
abstract: 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.
authors.affiliation: Analytical & Testing Center and ‡Key Laboratory of Green Chemistry and Technology of MOE in College of Chemistry, Sichuan University , Chengdu 610064, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
authors.forename: Ting
authors.initials: T
authors.lastname: Zhao
authors.forename: Jinyi
authors.initials: J
authors.lastname: Zhang
authors.forename: Lan
authors.initials: L
authors.lastname: Wu
authors.forename: Xiandeng
authors.initials: X
authors.lastname: Hou
mesh_terms: D045304:Cytochromes c / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D015335:Molecular Probes; D010447:Peptide Hydrolases / Q000737:chemistry*; D045663:Quantum Dots; D013440:Sulfides / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D017895:Manganese Compounds; D015335:Molecular Probes; D013440:Sulfides; D017967:Zinc Compounds; C041368:manganese sulfide; D045304:Cytochromes c; D010447:Peptide Hydrolases; C031238:zinc sulfide