Physical fundamentals of aptamer-based impedimetric biosensors with integrated microfluidics

This review examines the physical principles underlying impedimetric biosensors employing nucleic acid aptamers, emphasizing their conformational stability, binding thermodynamics, and intermolecular forces that govern ligand affinity. Electrochemical impedance spectroscopy (EIS) is analyzed as the central characterization tool, with discussion of charge transfer resistance, double-layer capacitance, and diffusion-limited processes modeled through equivalent circuits. Microfluidic integration is presented as a means to enhance analyte transport, reduce reagent consumption, and improve detection sensitivity via controlled fluid dynamics and electrokinetic effects. Functionalization strategies, particularly self-assembled monolayers, are reviewed alongside recent applications in protein, pathogen, toxin, and biomarker detection. Together, these interdisciplinary advances highlight the potential of aptamer-based impedimetric biosensors for next-generation diagnostic and environmental monitoring platforms.