Nitrogen Cobalt Co-doped FluorescentMagnetic Carbon Dots as Ratiometric Fluorescent Probes for Cholesteroland Uric Acid in Human Blood Serum

摘要

Detection of cholesterol and uric acid biomarkers is of great importance for clinical diagnosis of several serious diseases correlated with their variations in human blood serum. In this study, a new kind of well selective and highly sensitive ratiometric fluorescent probe for cholesterol and uric acid determination in human blood serum was innovatively developed on the basis of the inner filter effect (IFE) process of nitrogen, cobalt co-doped carbon dots (N,Co-CDs) with 2,3-diaminophenazine (DAP). DAP was the oxidative product during the oxidation reaction between o-phenylenediamine and H2O2. Fluorescent magnetic N,Co-CDs possessing blue emission and magnetic property were prepared through a facile one-pot hydrothermal strategy by using citric acid, diethylenetriamine, and cobalt(II) chloride hexahydrate as precursors. N,Co-CDs exhibited good ferromagnetic property and excellent optical properties even in extremely harsh environmental conditions, implying the huge potential applications of such N,Co-CDs in biological areas. On the basis of the IFE process between N,Co-CDs and DAP, N,Co-CDs were applied to establish ratiometric fluorescent probes for the indirectdetection of cholesterol and uric acid that participated in enzyme-catalyzedH2O2-generation reactions. The established IFE-basedfluorescent probes exhibited relatively low detection limits of 3.6nM for cholesterol and 3.4 nM for uric acid, respectively. The fluorescentprobe was successfully utilized for the determination of cholesteroland uric acid in human blood serum with satisfying results, whichprovided an informed perspective on the applications of such dopedCDs to explore the specific and sensitive nanoprobe in disease diagnosesand clinical therapy.