The carbon dots (C-dots) with high fluorescence quantum yield were prepared using hydrothermal method. C-dots have been adopted as probes for the fluorescence turn-off detection of H2O2 based on the special sensibility for the hydroxyl radical. And then the biosensors for the detection of substrate and enzymes activities were established in the acetylcholinesterase reaction system, which were related to the production of H2O2. Specifically, the proposed fluorescent biosensor was successfully applied to detect the concentration of choline (in the range from 0.025 to 50 μM) and acetylcholine (in the range from 0.050 to 50 μM), and the activity of choline oxidase (in the range from 1 to 75 U/L) and acetylcholinesterase (1 to 80 U/L). These results showed a sensitive, universal, nontoxic and eco-friendly detecting technique has been developed. Colloids and Surfaces B: Biointerfaces, 2014 (A) TEM image and (B) the photoluminescence spectrum of the C-dots. The insets in Fig. 1(B) are the photographs of the solution of C-dots under natural light (1) and UV light (254 nm) (2). (A) Time-dependent fluorescence changes of C-dots in the presence of H2O2 (30 μM) and Fe2+ (0.34 mM) (0 min, 3 min, 5 min, 10 min, and 15 min), (B) The change of the fluorescence intensity of C-dots vs. H2O2concentration in the presence of 0.34 mM Fe2+. Scheme of the fluorescent biosensing platform for the detection of H2O2-related substrates and enzymes based on C-dots. |
