论文部分内容阅读
Herein,we present the binding interaction between CdSe/ZnS quantum dots(QDs)and a novel multivalent peptide ligand with a thrombin cleavage sequence using fluorescence detection coupled to capillary electrophoresis(CE-FL)(scheme 1).When ATTO-H4 bound to QDs,ATTO-H4-QD assembly formed gradually and it was evidenced by the emergence of a new fluorescence emission signal at 625 nm(Fig.1,traces b~f).With the increment of the ATTO-H4/QD molar ratio,the F(o)rster resonance energy transfer(FRET)signal increased as well [1,2].At a molar ratio of 32:1(Fig.1,trace f),the ratio of the integrated peak area of the acceptor channel 625 nm and the donor channel 565 nm was 0.992,indicating abundant ATTO-H4 bound to QDs.Based on the high-sensitivity FRET signal in this ATTO-H4-QD system and the thrombin cleavage sequence in ATTO-H4,it could be applied to online thrombin detection.The molar ratio of 16:1(ATTO-H4/QD)was selected for the following experiments.When the concentration of thrombin was 2.5 μM(Fig.2,trace b),a new fluorescence emission signal at 625 nm emerged.It could be attributed to the breakage of the peptide spacer between the QDs and the ATTO-H4.When the concentration of thrombin increased(Fig.2,traces c~e),the FRET signals decreased while the new signal at 625 nm increased.Therefore,it is feasible to online detection of thrombin by this system.Our method extended the application of CE-FL in the online disease related enzyme detection.