Fluorometric and colorimetric sensor array for discrimination of glucose using enzymatic-triggered dual-signal system consisting of Au@Ag nanoparticles and carbon nanodots

Abstract

In the present study, a dual-signal senor for glucose detection has been established based on Au@Ag bimetallic core-shell nanoparticles (Au@Ag NPs) and carbon nanodots (C-dots). As a donor of surface plasmon-enhanced energy transfer (SPEET) in this senor, the fluorescence of C-dots was quenched by silver shell (acceptor) of the Au@Ag NPs. Furthermore, Au@Ag NPs serve as colorimetric reporter for the etching effect of H2O2 produced from enzymatic-triggered oxidation of glucose on silver shell, the fluorescence of C-dots recovery. Therefore, the change of color and fluorescence of this senor are directly related to the concentration of glucose. The linear relationship between fluorescence (absorbance) intensity and glucose was in the range of 2.0–400 μM (0.50–300 μM) with a low limit of detection of 0.67 μM (0.20 μM). Besides, this dual-signal senor also exhibited excellent selectivity for distinguishing glucose from common substances. This sensor system was successfully applied to the analysis of glucose in pretreated blood sample with satisfactory results, demonstrating the application prospect for practical sample analysis.