The escalating threat of infectious diseases necessitates the development of diagnostic technologies that are not only rapid and sensitive but also deployable at the point of care. Electrochemical impedance spectroscopy (EIS) has emerged as a leading technique for the label-free detection of pathogens, offering a unique combination of sensitivity, non-invasiveness, and adaptability. This review provides a comprehensive overview of the design and application of EIS-based biosensors tailored for pathogen detection, focusing on critical components such as biorecognition elements, electrode materials, nanomaterial integration, and surface immobilization strategies. Special emphasis is placed on the mechanisms of signal generation under Faradaic and non-Faradaic modes and how these underpin performance characteristics such as the limit of detection, specificity, and response time. The application spectrum spans bacterial, viral, fungal, and parasitic pathogens, with case studies highlighting detection in complex matrices such as blood, saliva, food, and environmental water. Furthermore, integration with microfluidics and point-of-care systems is explored as a pathway toward real-world deployment. Emerging strategies for multiplexed detection and the utilization of novel nanomaterials underscore the dynamic evolution of the field. Key challenges—including non-specific binding, matrix effects, the inherently low ΔR_ct/decade sensitivity of impedance transduction, and long-term stability—are critically evaluated alongside recent breakthroughs. This synthesis aims to support the future development of robust, scalable, and user-friendly EIS-based pathogen biosensors with the potential to transform diagnostics across healthcare, food safety, and environmental monitoring.

Considering the vital physiological functions of dopamine (DA) and uric acid (UA) and their coexistence in the biological matrix, the development of biosensing techniques for their simultaneous and sensitive detection is highly desirable for diagnostic and analytical applications. Therefore, Ti₃C₂T_x/rGO heterostructure with a double-deck layer was fabricated through electrochemical reduction. The rGO was modified on a porous Ti₃C₂T_x electrode as the biosensor for the detection of DA and UA simultaneously. Debye length was regulated by the alteration of rGO mass on the surface of the Ti₃C₂T_x electrode. Debye length decreased with respect to the rGO electrode modified with further rGO mass, indicating that fewer DA molecules were capable of surpassing the equilibrium double layer and reaching the surface of rGO to achieve the voltammetric response of DA. Thus, the proposed Ti₃C₂T_x/rGO sensor presented an excellent performance in detecting DA and UA with a wide linear range of 0.1–100 $\mathsf{\mu }$M and 1–1000 $\mathsf{\mu }$M and a low detection limit of 9.5 nM and 0.3 $\mathsf{\mu }$M, respectively. Additionally, the proposed Ti₃C₂T_x/rGO electrode displayed good repeatability, selectivity, and proved to be available for real sample analysis.

Copper-based materials are common industrial products which have been broadly applied to the fields of powder metallurgy, electrical contact, and heat exchangers, etc. However, the ease of surface oxidation limits the durability and effectiveness of copper-based components. Here, we have developed a powder metallurgy process to fabricate graphene/copper composites using copper powders which were first deposited with graphene layers by thermal chemical vapor deposition (CVD). The graphene/copper composites embedded with an interconnected graphene network was then able to be obtained by vacuum hot-pressing. After thermal oxidation (up to 220 °C) in humid air for several hours, we found that the degree of surface oxidation of our samples was much less than that of their pure Cu counterpart and our samples produced a much smaller increase of interfacial contact resistance when used as electrical contact materials. As a result, our graphene/copper composites showed a significant enhancement of oxidation resistance ability (≈5.6 times) compared to their pure Cu counterpart, thus offering potential applications as novel electrical contact materials.

A sensitive and selective electrochemical dopamine (DA) sensor has been developed using gold nanoparticles decorated marimo-like graphene (Au NP/MG) as a modifier of the glassy carbon electrode (GCE). Marimo-like graphene (MG) was prepared by partial exfoliation on the mesocarbon microbeads (MCMB) through molten KOH intercalation. Characterization via transmission electron microscopy confirmed that the surface of MG is composed of multi-layer graphene nanowalls. The graphene nanowalls structure of MG provided abundant surface area and electroactive sites. Electrochemical properties of Au NP/MG/GCE electrode were investigated by cyclic voltammetry and differential pulse voltammetry techniques. The electrode exhibited high electrochemical activity towards DA oxidation. The oxidation peak current increased linearly in proportion to the DA concentration in a range from 0.02 to 10 μM with a detection limit of 0.016 μM. The detection selectivity was carried out with the presence of 20 μM uric acid in goat serum real samples. This study demonstrated a promising method to fabricate DA sensor-based on MCMB derivatives as electrochemical modifiers.

It is of great significance to distinguish enantiomers due to their different, even completely opposite biological, physiological and pharmacological activities compared to those with different stereochemistry. A sp³-to-sp² converted highly stable and regenerative graphene/diamond electrode (G/D) was proposed as an enantiomer recognition platform after a simple β-cyclodextrin (β-CD) drop casting process. The proposed enantiomer recognition sensor has been successfully used for d and l-phenylalanine recognition. In addition, the G/D electrode can be simply regenerated by half-minute sonication due to the strong interfacial bonding between graphene and diamond. Therefore, the proposed G/D electrode showed significant potential as a reusable sensing platform for enantiomer recognition.

Copper powder has broad applications in the powder metallurgy, heat exchanger, and electronic industries due to its intrinsically high electrical and thermal conductivities. However, the ease of formation of surface oxide or patina layer raises difficulty of storage and handling of copper powder, particularly in the case of Cu microparticles. Here, we developed a thermal chemical vapor deposition chemical vapor deposition (CVD) process for large-scale synthesis of graphene coatings on Cu microparticles, which importantly can remain monodisperse without aggregation after graphene growth at high temperature by using removal spacers. Compared to other protective coating methods, the intrinsic electrical and thermal properties of Cu powder would not be degraded by uniform growth of low defect few-layer graphene on each particle surface. As a result, when the anticorrosion performance test was carried out by immersing the samples in Cu etchant, the corrosion rate of graphene/Cu microparticles was significantly improved (ca three times slower) compared to that of pristine Cu powder, also showing a comparable anticorrosion ability to commercial CuZn30 alloy.