Review of Magnetic Nanomaterials for the Electrochemical Sensing of Antibiotics

Antimicrobial resistance (AMR) is increasing worldwide. This is due to the widespread and often uncontrolled release of antibiotics into surface water, drinking water, and the food chain. The traces of antibiotics (ng/L to μg/L) bioaccumulate, disrupt ecosystems, and accelerate AMR, yet regulatory monitoring remains inadequate. Sensitive analytical methods for the detection and quantification of antibiotics at trace levels in complex matrices are therefore essential. Conventional techniques, i.e., liquid or gas chromatography, mass spectrometry, and capillary electrophoresis, offer high accuracy but are associated with costly instrumentation, lengthy workflows, and extensive sample preparation. Electrochemical sensors based on advanced nanomaterials, particularly magnetic nanoparticles (MNPs), have attracted considerable interest due to their advantages in sensitivity and selectivity, wide linear dynamic ranges, extremely low limits of detection (LOD) and quantification (LOQ), low instrument cost, and rapid response. This review provides a critical overview of recent advances in MNP-based electrochemical platforms for antibiotic detection. The focus is on wet-chemical synthesis routes, modification approaches, and strategies for integrating magnetic nanocomposites into electrodes. Synergistic improvements through hybrid architectures are emphasized, combining MNPs with carbon nanomaterials, biopolymers, metal–organic frameworks, and molecularly imprinted polymers. Trends over the last five years have shown that applications in environmental monitoring, food safety, and drinking water are increasing. We summarize the key performance metrics, outline the current technical bottlenecks, such as long-term stability and large-scale manufacturing, and provide an outlook for the future. Taken together, these developments position MNP-based electrochemical sensors as versatile, highly effective tools for curbing antibiotic pollution and slowing the advancement of AMR.