Transduction strategies in enzyme-free nanomaterial-based aptasensors for tetracycline antibiotics: A review

Abstract

Enzyme-free aptamer-based biosensors have gained increasing attention for tetracycline monitoring, yet existing studies remain highly fragmented across materials and sensing formats. This review presents a mechanistic framework that systematically classifies optical and electrochemical aptasensors by their transduction pathways rather than by individual nanomaterials. Representative fluorescence, colorimetric, SERS, SPR, chemiluminescence, electrochemical impedance, voltammetric, photoelectrochemical, and electrochemiluminescent systems are critically compared to elucidate how aptamer conformational changes, interfacial interactions, and signal amplification mechanisms govern analytical performance. Beyond reporting detection limits, the review emphasizes real-sample applicability, discussing matrix effects, cross-selectivity among tetracycline analogues, and practical deployment constraints. Comparative analysis with conventional methods highlights biosensors as complementary tools for rapid, decentralized screening rather than direct replacements for laboratory-based quantification. Finally, emerging directions, including microfluidic integration, miniaturized readout systems, and intelligent data processing, are outlined as key strategies toward robust, portable, and field-deployable tetracycline-sensing platforms.