Nitrogen-Doped Carbon Dots as A New Substrate for Sensitive Glucose Determination.

Hanxu Ji,Jiangjiang Gu,Kai Xi,Xudong Jia,Chen Shu,Feng Zhou

doi:10.3390/s16050630

Abstract

Nitrogen-doped carbon dots are introduced as a novel substrate suitable for enzyme immobilization in electrochemical detection metods. Nitrogen-doped carbon dots are easily synthesised from polyacrylamide in just one step. With the help of the amino group on chitosan, glucose oxidase is immobilized on nitrogen-doped carbon dots-modified carbon glassy electrodes by amino-carboxyl reactions. The nitrogen-induced charge delocalization at nitrogen-doped carbon dots can enhance the electrocatalytic activity toward the reduction of O2. The specific amino-carboxyl reaction provides strong and stable immobilization of GOx on electrodes. The developed biosensor responds efficiently to the presence of glucose in serum samples over the concentration range from 1 to 12 mM with a detection limit of 0.25 mM. This novel biosensor has good reproducibility and stability, and is highly selective for glucose determination under physiological conditions. These results indicate that N-doped quantum dots represent a novel candidate material for the construction of electrochemical biosensors.

Highlights

Carbon dots (CDs), a relatively new member of the carbon nanomaterial family, were first obtained during purification of single-walled carbon nanotubes in 2004 [1]
N-doped CDs are synthesized by the method which our group recently reported
The successful synthesis of N-doped CDs could be observed in the amide functions

Summary

Introduction

Carbon dots (CDs), a relatively new member of the carbon nanomaterial family, were first obtained during purification of single-walled carbon nanotubes in 2004 [1]. They are generally oxygenous carbon nanoparticles with a size of less than 10 nm. Just like heavy-metal-based quantum dots (QDs), they exhibit several promising advantages over organic fluorescence dyes, such as tunable luminescence emission, high stability against photobleaching and blinking. Zhu and co-workers reported a facile and high-output method for the fabrication of CDs with a quantum yield as high as 80%. Yu and co-workers displayed a new type of CDs which could form a fluorescence resonance energy transfer (FRET) system with an organic dye.

Methods

Results

Conclusion