Glucose sensors have made great progress during decades of development and recently graduated into the fourth generation of nonenzymatic glucose sensors after experienced three generations of enzymatic glucose sensors. In this paper, the detecting principles of both enzymatic and nonenzymatic glucose sensors are introduced. The research advances for the application of nanomaterials in nonenzymatic glucose sensors are reviewed. The preparation methods of different nanomaterials together with the sensitivity, selectivity, detection range and stability of the constructed sensors are remarked extensively. Moreover,the main causes for the restriction of the commercial application of nonenzymatic glucose sensors are analyzed. Among them, precious metal nanomaterials involve platinum, gold and palladium, transition metal nanomaterials involve nickel, copper and their oxides, double metal nanomaterials involve alloy and compound, carbon nanomaterials involve single or multi-walled carbon nanotubes and graphene. In addition, the outlook of future development directions and trends of nonenzymatic glucose sensors are given.

Contents
1 Introduction
2 Classification and detecting principle of glucose sensors
2.1 Glucose oxidase glucose sensors
2.2 Nonenzymatic glucose sensors
3 Research advances of nonenzymatic glucose sensors
3.1 Nonenzymatic glucose sensors based on metal and metal oxides
3.2 Nonenzymatic glucose sensors based on bimetal
3.3 Nonenzymatic glucose sensors based on carbon materials
4 Conclusion and outlook