The utilization of electrochemical detection techniques in paper-based analytical devices (PADs) has revolutionized point-of-care (POC) testing, enabling the precise and discerning measurement of a diverse array of (bio)chemical analytes. The application of electrochemical sensing and paper as a suitable substrate for point-of-care testing platforms has led to the emergence of electrochemical paper-based analytical devices (ePADs). The inherent advantages of these modified paper-based analytical devices have gained significant recognition in the POC field. In response, electrochemical biosensors assembled from paper-based materials have shown great promise for enhancing sensitivity and improving their range of use. In addition, paper-based platforms have numerous advantageous characteristics, including the self-sufficient conveyance of liquids, reduced resistance, minimal fabrication cost, and environmental friendliness. This study seeks to provide a concise summary of the present state and uses of ePADs with insightful commentary on their practicality in the field. Future developments in ePADs biosensors include developing novel paper-based systems, improving system performance with a novel biocatalyst, and combining the biosensor system with other cutting-edge tools such as machine learning and 3D printing.

Electrochemical sensors have emerged as powerful analytical tools for the detection of anti-inflammatory and antibiotic drugs due to their high sensitivity, rapid response, and cost-effectiveness compared to conventional chromatographic and spectrophotometric methods. This review highlights recent advances in electrode materials, surface modification strategies, and signal amplification approaches for quantifying nonsteroidal anti-inflammatory drugs (NSAIDs) and various antibiotic classes, including sulfonamides, tetracyclines, macrolides, and quinolones. Particular attention is given to nanostructured carbon-based materials, metal nanoparticles, and polymer composites that enhance electron transfer, improve selectivity, and lower limits of detection (LODs). The analytical performance of different electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, and square-wave voltammetry is critically compared across various drug targets. Trends indicate that hybrid nanomaterial-modified electrodes consistently achieve sub-micromolar detection limits in biological and environmental samples, offering potential for point-of-care diagnostics and environmental monitoring. Current challenges include improving sensor stability, mitigating fouling effects, and ensuring reproducibility in complex matrices. Future research should focus on integrated, miniaturized sensing platforms capable of multiplex detection, paving the way for rapid, portable, and sustainable analytical solutions in pharmaceutical and biomedical applications.

This study investigated the behavior of thin films of graphene oxide (GO) and chemically converted graphene (CCG) on a glassy carbon surface in the presence of two redox probes (Fe(CN)³⁻ ₆/Fe(CN)⁴⁻ ₆ and O₂), employing cyclic voltammetry, electrochemical impedance spectroscopy, and hydrodynamic voltammetry as a simple procedure for characterizing these films. The feasibility of using these electrochemical techniques for this purpose opens up the possibility of applying them to biosensors and electrocatalysts using surface-supported GO and CCG materials. Raman spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and scanning electron microscopy were employed to characterize GO and CCG.

This study investigated the synthesis of graphene oxide nanoribbons (GONRs) and graphene nanoribbons (GNRs) from multiwalled carbon nanotubes (MWCNTs), and the behavior of thin films of MWCNTs, GONRs, and GNRs on a glassy carbon surface in the presence of two redox probes (Fe(CN)₆ ³⁻/Fe(CN)₆ ⁴⁻ and O₂) employing cyclic voltammetry, electrochemical impedance spectroscopy, and hydrodynamic voltammetry (HV) as a simple procedure for characterizing these films. The feasibility of using these electrochemical techniques for this purpose opens up the possibility of applying them to biosensors and electrocatalysts using surface-supported MWCNT, GONR, and GNR materials. GNR1 resembles an internodal segment of bamboo cut lengthwise, with a shallow troughing at its center, while GNR2 resembles stacked ribbons, each ∼16 nm wide, with points of structural damage and points of four-ribbon connection measuring 60 nm or wider, sufficiently catalytic for the oxygen reduction reaction to occur, unlike the other modified electrodes investigated in acidic, 0.1 M KH₂PO₄ (pH 7.0), and 0.1 M KOH solutions (HV results). Transmission electron microscopy and thermogravimetric analysis were employed to characterize the MWCNTs, GONRs, and GNRs.