Enzyme-based and enzyme-free metal-based glucose biosensors: Classification and recent advances

Glucose Oxidase Patterned Meta‐Chemical Surface for Sensing Glucose Using Dip‐Pen Nanolithography

“…Using the MCSITO and MCSAumicrux electrodes, the oxidation waves obtained at ~$${0.9}$$ V and $${0.75}$$ V (Figure 4a and Figure 4b, respectively) could indicate the occurrence of glucose oxidation according to reaction (1) [28] . These new types of electrodes are third‐generation sensors in which glucose measurement is direct [58,59] $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm G}{\rm O}{\rm D}{\rm }\left({\rm F}{\rm A}{\rm D}\right)+{{\rm C}}_{6}{{\rm H}}_{1}2{{\rm O}}_{6}\rightarrow {\rm G}{\rm O}{\rm D}{\rm }\left({\rm F}{\rm A}{\rm D}{{\rm H}}_{2}\right)+{{\rm C}}_{6}{{\rm H}}_{1}0{{\rm O}}_{6}\hfill\cr}}$$$ …”

“…[28] These new types of electrodes are third-generation sensors in which glucose measurement is direct. [58,59] GOD FAD…”

CuO/CoZn-Layered Double-Hydroxide Nanowires on Carbon Cloth as an Enzyme-Free H2O2 Sensor

“…Usually, the traditional electrochemical sensors use enzymes (for example, catalase and horseradish peroxidase) for H 2 O 2 detection based on the direct electron transfer between redox enzymes and electrodes. However, limited by the high price, easy to denaturation and deactivation, and the complicated production process of the enzyme, enzyme-based sensors cannot meet diversified needs in practical applications. , In comparison, enzyme-free sensors have the advantages of simple electrode preparation, stable use, and sensitive detection, so enzyme-free sensors have been widely concerned. , The electrode materials in enzyme-free sensors are generally precious metals, , transition metals, , carbon, , and conductive polymers. , Among them, transition metals are abundant, have a variety of valence states as well as high electrocatalytic activity, and are often chosen as electrode-modifying materials for enzyme-free sensors. , …”

A paper-based dual functional biosensor for safe and user-friendly point-of-care urine analysis

“…As for the electrochemical glucose sensors, although four generations of sensing strategies have been reported, 21 the first one, which relied on the enzymic oxidation of glucose and successive oxidation of H 2 O 2 , 22 remains the most attractive method in both scientific and industrial settings due to its simple design, high sensitivity, selectivity of enzymes, and good biocompatibility. 23–25 However, in this configuration, when the GOx are in direct contact with the electrode or interference proteins deposit around the redox centre of GOx, its enzymatic activity and the electron transport efficiency between GOx and the electrode will be significantly reduced. 26,27 To tackle this issue, many methods have been demonstrated to be effective, such as using chitosan as an isolation and protection layer for GOx 28 and nanomaterials to shorten the electron transport distance between the redox centre and the electrode surface.…”