L-noradrenaline functionalized near-infrared fluorescence CdSeTe probe for the determination of urea and bioimaging of HepG2 Cells

Abstract

In this paper, near-infrared (NIR) light emitting L-noradrenaline functionalized CdSeTe QDs (NA-CdSeTe) were synthesized and applied to the biosensing of urea. When the pH value of NA-CdSeTe solution was adjusted from neutral to alkalinity, the noradrenaline on the surface of QDs would turn to quinone, which triggered the fluorescence quenching of NA-CdSeTe probe due to the charge transfer interactions between QDs and the proximal quinone. Based on the fact that the hydrolysis of urea in the presence of urease would release OH− and slightly change the pH value of the solution, the fluorescence intensity of NA-CdSeTe QDs could be linked to the enzymatic degradation of urea. The novel urea-biosensing system could effectively determinate urea in the dynamic concentration range from 0.057 to 13mmol/L. Furthermore, NA-CdSeTe probe could serve as an “optical window” for the bioimaging of urea with high selectivity in the serum samples and HepG2 cells. The urea-bioimaging system could effectively probe urea in the dynamic concentration range from 0.2 to 5mmol/L. This NIR probe was excellent candidate not only for its sensitive with urea but also its real-time bioimaging. We expected that this NIR probe based strategy could pave the way for developing simple, no enzyme immobilization required and good sensitive method related detections for further medical applications.