Multicolor Colormetric Biosensor for the Determination of Glucose based on the Etching of Gold Nanorods.

Yue Lin,Mengmeng Zhao,Yajuan Guo,Bin Qiu,Guonan Chen,Zhenyu Lin,Longhua Guo,Fang Luo,Xiaoming Ma

doi:10.1038/srep37879

Abstract

In this work, 3,3′,5,5′-tetramethylbenzidine(II) (TMB2+), derived from H2O2-horseradish peroxidase (HRP)-3,3′,5,5′-tetramethylbenzidine (H2O2-HRP-TMB) reaction system, was used to etch AuNRs to generate different colors of solution. Many enzyme reactions are involved in the production of H2O2 (e.g., glucose can react with the dissolved oxygen in the presence of glucose oxidase (GOx) to produce H2O2). Given this information, a simple visual biosensor was developed in this study, with glucose as the example target. The detection range of the proposed system varied with the experimental conditions, such as the concentration of GOx and HRP, and enzymatic reaction time. Under the optimized conditions, the longitudinal shift of localized surface plasmon resonances (LSPR) had a linear correlation with the glucose concentration in the range of 0.1~1.0 mM. Meanwhile, the solution displayed a specific color in response to the glucose concentration, thus enabling the visual quantitative detection of glucose at a glance. Compared with the traditional monochromic colorimetry, this multicolor glucose sensor generates various vivid colors, which can be easily distinguished by naked eyes without any sophisticated instrument. Notably, the proposed method has been successfully applied to detect glucose in serum samples with satisfied results.

Highlights

Because Cu2+ can catalyze H2O2-AuNRs etching system[18,19]
The TMB2+ just presents various shades of yellow, which is difficult for discrimination of human eyes, the mixture solution of AuNRs and cetyltrimethyl ammonium bromide (CTAB) is added to the TMB2+ solution with sufficient mixing
AuNRs can react with TMB2+ to produce TMB0, and Au was oxidized into Au(I)

Summary

Introduction

Because Cu2+ can catalyze H2O2-AuNRs etching system[18,19]. A promising strategy was reported to detect Fe3+ through selective etching of Au NRs at room temperature[13]. A method was developed for blood glucose detection based on enzymatic etching of AuNRs by horseradish peroxidase (HRP)[20]. Different concentrations of glucose (50 μL) were added to 96-well plates at room temperature, and 400 μL of GOx (0.1 mg/mL), 400 μL of HRP (4 μg/mL) and 1 mL of TMB liquid substrate were added to the 4 mL centrifuge tube with sufficient mixing.

Results

Conclusion