Copper Micropillar Array-Based Nonenzymatic Glucose Sensor With Face-to-Face Structure for High Current Sensing

Enhancing the sensor’s resistance to interference, vital for practical applications, can be accomplished by improving the sensor’s response current signal. Most of the research on sensors has focused on electrode materials, and more research is needed on how to increase the current through structural changes. In this study, the glucose sensor structure was improved compared to the traditional planar design by implementing a face-to-face (FtF) parallel electrode structure. A copper micropillar array (Cu<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> PA) electrode with a larger surface area was employed as the working electrode (WE) to enhance the sensor’s current response. Initially, the surface reaction processes of the Cu<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> PA WE were investigated. Subsequently, the influence of electrode spacing on the sensor’s current density was examined, revealing a decrease in current density with increasing spacing, particularly in high-concentration solutions. Finally, the detection performance of the sensor with a spacing of 0.5 mm was studied, demonstrating a linear range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5~\mu $ </tex-math></inline-formula> M–9.814 mM, a sensitivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$564~\mu $ </tex-math></inline-formula> A mM<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula> cm<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{2}}$ </tex-math></inline-formula>, and a low detection limit of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.7~\mu $ </tex-math></inline-formula> M (S/N = 3). The sensor exhibited a current density of 7.016 mA/cm2, which is over seven times that of commercial strips. The changes in electrode structure and WE resulted in significantly higher current density and improved detection performance of the sensor, suggesting a promising new strategy for sensor design.