Ahmet Cetinkaya

Activation of glassy carbon electrodes (GCEs) in tailored solution environments introduces oxygenated surface functionalities such as hydroxyl, carboxyl, and quinone groups. These modifications enhance electron‐transfer kinetics and strengthen interactions with target analytes, thereby improving electrochemical sensitivity. In this study, square-wave voltammetry was used, and the most suitable supporting electrolyte for tryptophan (TRP) analysis was a pH 3 Britton–Robinson buffer. The cyclic voltammetry potential range and number of cycles for the Act-GCE were obtained as 0–1.5 V and seven cycles, respectively. The activated electrode exhibited excellent analytical performance, with a linear response for TRP over 0.20–6.28 μM, a detection limit of 0.06 μM, and a quantification limit of 0.20 μM. Its practical applicability was confirmed by recovery tests of yogurt samples, demonstrating accurate and reliable real-sample analysis. Scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy were used for both electrochemical and morphological characterization. For TRP analysis of yogurt samples, the square wave voltammetry results obtained with the Act-GCE showed strong agreement with liquid chromatography-mass spectrometry data, and a statistical evaluation confirmed no significant difference between the two methods (p = 0.17). Moreover, the electrode material was used reliably to determine TRP in a yogurt sample with excellent recovery.

Malaria remains to be one of the deadliest infectious illnesses and is especially common in underdeveloped and developing countries. Recent advances (2022–2025) in biosensor engineering, nanomaterials, and microfluidic automation have significantly expanded the capabilities of point-of-care diagnostic technologies for malaria. With the guidance of the World Health Organization (WHO) and the international community, malaria-endemic lands have achieved measurable advances in disease control and elimination. Globally, we are witnessing an increase in cases of clinically atypical malaria and asymptomatic carriers, which contributes to misdiagnosis and missed diagnosis. Other challenges include climate change, socioeconomic inequality, limited healthcare infrastructure, the emergence of new vector species, and increasing resistance to antimalarial drugs and insecticides. This shows that additional efforts will be needed if malaria is to be eradicated. Creating simple, practical, and affordable integrated biosensors is essential to diagnose early-stage malaria. In this context, one of the main challenges is converting complex biosensor techniques into affordable point-of-care testing (POCT) technologies that could be employed close to the patient without requiring skilled professionals or special infrastructures. Unlike recent reviews that primarily focus either on biomarker discovery or broadly on POC technologies, this work provides a comparative and mechanistic evaluation of electrochemical, optical, and piezoelectric biosensors, emphasizing primary research articles. Particular attention is given to signal transduction mechanisms, analytical trade-offs, microfluidic integration strategies, and real-world deployability considerations. This review gives general information about the biomarkers used for malaria diagnosis and summarizes some prominent examples of biosensors described in previous studies for malaria detection POCT making use of different transduction formats. The work finishes with some general conclusions, demanding to progress the design of portable point-of-care diagnostic technologies and further research to achieve sensitive quantification of biomarker panels as the key to the future of malaria detection and global control. Graphical Abstract

Cefuroxime (CFR), a second-generation cephalosporin antibiotic, is widely prescribed for the treatment of various bacterial infections due to its broad-spectrum antimicrobial activity. Accurate and sensitive quantification of CFR in biological and pharmaceutical matrices is crucial to ensure therapeutic efficacy and to prevent potential adverse effects. In this work, a molecularly imprinted polymer-based electrochemical sensor, enhanced with gold nanoparticles, was developed for the selective and ultrasensitive determination of CFR by electropolymerizing 1H-indazole-5-boronic acid as the functional monomer and aniline (ANI) as the co-monomer on a glassy carbon electrode. The incorporation of gold nanoparticles (AuNPs) significantly improved the sensor’s electrochemical performance by increasing the effective surface area and facilitating electron transfer. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and scanning electron microscopy (SEM) were used to confirm the successful formation of selective recognition sites and the sensor's functional integrity. Under optimized conditions, the developed molecularly imprinted polymer-based sensor exhibited excellent linearity over the concentration range of 1.00 × 10-11 M to 3.75 × 10-10 M, with a remarkably low limit of detection (LOD) of 1.59 × 10-12 M in standard solutions. Selectivity studies demonstrated that the sensor retained high specificity for CFR even in the presence of structurally related cephalosporins, including cefazolin, cefdinir, cefixime, ceftazidime, and ceftriaxone. Furthermore, the sensor's analytical applicability was successfully validated using biological samples and vial formulations containing injectable powder, confirming its robustness and practical utility.