Fabrication and Characterization of MgO-Based Enzymatic Glucose Biosensors

An enzymatic glucose biosensor based on magnesium oxide (MgO) film potential measurement is proposed, in which glucose oxidase (GOD) is used to enhance the glucose sensing performance. And according to the chemical properties of MgO, GOD was immobilized on the working electrode using (3-aminopropyl)triethoxysilane (APTES) and glutaraldehyde (GA). The top layer of the sensor is Nafion to enhance the selectivity of glucose. The film substrate of the sensor adopts a flexible printed circuit board (FPCB) with excellent chemical properties, and MgO is deposited on the working electrode by a radio frequency (RF) sputtering process. The MgO coated on the film has a thickness of about 100 nm, measured by field emission scanning electron microscopy. X-ray photoelectron spectroscopy (XPS) analysis confirmed that the sensor mainly comprises MgO elements. The sensing capability of this sensor pair is the potentiometric measurement by time–voltage (V–T) measurement method. The glucose concentration measurement range is linear from 2 to 10 mM. Regarding average sensitivity, linearity, response time, interference effect, and limit of detection (LOD), multiple experimental results show that the MgO enzymatic glucose biosensor has excellent average sensing performance compared with traditional glucose biosensors.