Role of Electrode Microstructuration in Electrochemical Aptamer-Based Biosensors for Localized Measurements

Miniaturized electrochemical aptamer-based biosensors (E-AB) can help characterize various systems at the microscopic scale. However, translation from macro- to microscale remains challenging, as it involves reduced signal-to-noise, which can be overcome via electrode microstructuration to increase the number of surface-attached aptamers. Doing so, however, has sporadically shown impacts on the sensors' analytical performance, warranting further exploration. In response, we compare miniaturized E-ABs' figures of merit of similar electroactive surface areas when polished or microstructured to evaluate the impact of surface microstructuration on their analytical performance. While electrode microstructuration provided minimal improvements in the sensors' limits of detection, it increased their stability. Using these, we then successfully monitor local variations in target concentrations near an artificial substrate─a demonstration we envision will pave the way toward specific measurements of molecules at the microscopic scale.