Electrochemical impedance aptasensors for environmental emerging contaminants: Interfacial nanodesign, nucleic acid signal amplification and analytical translation

Trace emerging contaminants (ECs) including antibiotics, heavy metals and endocrine-disrupting substances widely exist in environmental and food matrices, posing long-term ecological and human health hazards. Conventional chromatographic-mass spectrometric techniques require complicated pretreatment and high testing costs, which limits their application in field rapid analysis. Existing reviews separately discuss electrode materials or signal amplification strategies, without a comprehensive collation integrating the two technical modules for full-spectrum EC detection. This review systematically summarizes electrochemical impedance aptasensor research progress for EC monitoring. Six categories of electrode modification substrates are classified, and their effects on electron transfer efficiency and aptamer immobilization capacity are summarized. Enzyme-assisted, CRISPR-Cas-mediated, enzyme-free nucleic acid self-assembly, DNA origami and molecular imprinting amplification approaches are reviewed, with their impedance signal boosting mechanisms described. Published analytical parameters covering linear ranges and limits of detection are tabulated to compare sensor performance against seven ECs subgroups. Differences in interfacial signal transduction induced by metal ions, small organic molecules and biological toxins are illustrated. Universal challenges such as matrix interference and inconsistent batch performance of sensors are sorted out based on reported experimental results. Reported data demonstrate that composite electrode materials and combined amplification systems can reduce detection thresholds. Restrictions including poor long-term interfacial stability and absent unified evaluation criteria are recorded. Research routes covering aptamer rational design, antifouling interfaces, multi-channel sensing arrays and portable sensing equipment are outlined. This review provides systematic data and mechanism references for the construction of impedance aptasensors used in environmental and food safety detection.