Recent Advances in Electrochemical Aptamer Sensors: Materials Design, Antifouling Strategies, and Toward Miniaturized and Wearable Applications

Electrochemical aptamer sensors integrate the molecular recognition capability of aptamers with electrochemical or electronic signal readout, offering promising tools for environmental monitoring, clinical diagnostics, point-of-care testing, and continuous molecular monitoring. However, their practical performance is not determined by sensitivity alone. Nonspecific adsorption, interfacial instability, signal drift, impaired electron transfer, and architecture-dependent limitations such as Debye screening remain major barriers to reliable application in complex samples. This review summarizes recent progress in electrochemical aptamer sensors from an architecture- and application-oriented perspective. We first classify major electrochemical aptamer sensor architectures according to their signal-transduction mechanisms, including redox-tagged structure-switching sensors, capture/release or signal-amplified sensors, and field-effect transistor-based aptasensors. We then discuss how electrode fabrication, electrode and interface materials, aptamer immobilization, antifouling strategies, and integrated sensing platforms support or limit these architectures. Rather than evaluating sensors only by detection limit, we highlight the distinct requirements of different analytical scenarios. Endpoint assays may benefit from nanomaterial-enhanced amplification and disposable electrode formats, whereas wearable or implantable monitoring requires reversible recognition, stable baselines, antifouling protection, and calibration-free or calibration-minimized operation. Finally, we discuss remaining challenges and future directions for translating electrochemical aptamer sensors toward robust real-world applications.