Microchimica Acta最新文献

An electrochemical chiral sensor based on β-cyclodextrin@Ti₃C₂T_x MXene/screen printed carbon electrode (β-CD@MXene/SPCE) was developed for the determination of D- and L-tyrosine enantiomers for the first time. Morphological characterization of the material (β-CD@MXene) was performed using Field Emission-Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) imaging, while X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the crystalline structure and interaction between MXene and β-CD in structural characterization. To evaluate the electrochemical characterization of the modified electrodes, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were applied. To investigate the electrochemical behavior of the tested D- and L-amino acid enantiomers, CV and differential pulse voltammetry (DPV) techniques were conducted. Among the tested chiral species, only D- and L-tyrosine showed distinct voltammetric signals. To investigate the electrochemical behavior of D- and L-tyrosine, CV and DPV techniques were conducted revealing an increase in oxidation peak currents with the increasing tyrosine concentration levels. The voltammetric response of racemic D/L-tyrosine was also examined. For real sample analysis, human serum was used in chronoamperometric measurements (10–100 µM), yielding a linear response. The LOD and LOQ values were 3.15 µM and 9.45 µM, respectively, for D-tyrosine, and 4.68 µM and 14.05 µM, respectively, for L-tyrosine in human serum samples.

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MicroRNAs (miRNAs) serve as critical biomarkers for cancer diagnosis, yet their detection faces challenges by their extremely low absolute abundance in clinical samples. Existing cascade detection strategies based on rolling circle amplification are often limited by nonspecific hybridization caused by sequence interference, which compromises sensing performance. To address this, we developed a novel cascade amplification strategy by integrating an entropy-driven DNA circuit (EDC) with no promoter rolling circle transcription (NP-RCT) to achieve highly sensitive, label-free detection of miRNA. The core innovation of this approach is the design of a single-stranded DNA probe that self-folds into a dumbbell structure, functioning simultaneously as both the EDC product and the transcription template. This dual-role design prevents sequence crossover between the two reaction systems and eliminates promoter dependency. The thymine-rich sequence in the dumbbell loop improves transcription efficiency, and the poly-adenine RNA generated by transcription can directly guide the in-situ synthesis of fluorescent gold nanoclusters. The sensor demonstrates a detection limit of 9.6 pM for miRNA-21 with single-base mismatch specificity. Moreover, it exhibits favorable performance in detecting miRNA-21 within complex biological samples, effectively distinguishing cancer cells from normal cells through the analysis of total RNA extracts. This study provides a new strategy for achieving sensitive and specific detection of miRNAs.

A novel 2-mercaptobenzothiazole (2-MBT) detection method is introduced based on ultrathin PtRuFeCoRhW high-entropy alloy nanorods (HEANRs) synthesized via a solvothermal-coreduction strategy. These HEANRs contained numerous defects and atomic steps, providing abundant active sites. It exhibited peroxidase (POD)-like activity for its entropy-driven catalytic synergy and modified electronic structure, which was utilized to construct a colorimetric sensing platform. The platform operates via competitive inhibition between 2-MBT and 3,3’,5,5’-tetramethylbenzidine (TMB) oxidation, enabling ultrasensitive 2-MBT detection with a linear range of 1–7 µM (R² = 0.997) and a detection limit of 0.42 µM (S/N = 3). Notably, the sensor demonstrates reliable performances in practical analysis of rubber wastewater. This work provides an efficient method for detecting 2-MBT. It also demonstrates that entropy-driven structural engineering is a promising strategy for designing advanced high-entropy materials. This research advances high-entropy-initiated catalysis and offers a versatile platform for environmental remediation, addressing a broad range of analytical challenges.

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Surface plasmon resonance (SPR) biosensors have emerged as powerful analytical tools due to their label-free operation, real-time monitoring capability, and broad dynamic detection range, making them highly attractive for clinical, environmental, and food analysis. Despite significant progress over the past decade, the performance of SPR biosensors in real-world applications remains strongly limited by challenges related to sensor construction, surface functionalization, nanomaterial integration, and matrix effects in the analysis of complex samples. This review critically examines recent advances in SPR biosensor design with an emphasis on how construction strategies and functional nanomaterials influence analytical performance. Particular attention is given to the optimization of biomolecule immobilization and nanostructured interfaces as key factors governing sensitivity, selectivity, and robustness. Current limitations associated with nonspecific interactions and complex biological matrices are discussed, highlighting remaining gaps between laboratory performance and practical implementation. By addressing these challenges, this review provides a consolidated perspective on design principles required to improve the reliability and applicability of SPR biosensors, supporting their future development for clinically relevant diagnostics, environmental monitoring, and agronomic analysis.

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Ion-selective nanosensors enable ions monitoring in live cells, yet most existing optode platforms rely on limited matrix materials with constrained functionalization and stability. Here, polydopamine (PDA) nanoparticles were integrated with ionophore based ion selective sensing principle to generate stable, tunable nanosensors for potassium (K⁺) and calcium (Ca²⁺) detection. The PDA matrix enhanced sensitivity through its negatively charged microenvironment and enabled straightforward surface functionalization with cysteamine and glutathione to promote cellular interaction and uptake. The nanosensors exhibited broad dynamic ranges (0.1 mM-0.1 M for K⁺ and 1 µM-0.1 M for Ca²⁺), high selectivity over competing ions, excellent colloidal stability, and minimal cytotoxicity. Importantly, PDA-based nanosensors enabled real-time visualization of intracellular K⁺ dynamics in live cells. These results establish PDA as a promising and adaptable matrix for next-generation ion-selective nanosensors in biological environments.

A portable functionalized multi-emissive MOF-based thin-film sensor (OPA-MEMOF@PVA) was developed for the rapid, sensitive, and selective detection of NH₄⁺-N. The sensor was fabricated by first modifying 4-bromophthalaldehyde (OPA) onto a multi-emissive metal-organic framework (MEMOF), followed by blending with polyvinyl alcohol (PVA). Under optimized conditions, the thin-film sensor exhibited excellent NH₄⁺-N detection performance, achieving a low limit of detection (LOD) of 69.2 nM and a response time of 3 min. Furthermore, OPA-MEMOF@PVA manifested outstanding selectivity and robust anti-interference ability towards NH₄⁺-N. The enhanced detection performance is most consistent with the effective adsorption and enrichment of NH₄⁺-N by the functionalized MOF, combined with a specific interaction between the dialdehyde groups of OPA-MEMOF and NH₄⁺-N. When applied to real groundwater samples, the thin-film sensor demonstrated satisfactory recoveries (97–103%) with a relative standard deviation (RSD) of less than 3%. Owing to its rapid response, portability, and high selectivity, OPA-MEMOF@PVA shows great promise as a reliable sensing platform for on-site NH₄⁺-N detection.

As crucial biomarkers, the rapid and sensitive detection of dopamine (DA) and uric acid (UA) is essential for disease prevention and diagnosis. In this study, MoS₂/MoO₂ heteronanorod modified N-doped porous carbon nanofiber (N-PCNFs@MoS₂/MoO₂) sensing electrodes for the simultaneous detection of DA and UA were fabricated by electrostatic spinning coupled with vulcanization reaction. The carbonization treatment of the ZIF-8/PAN precursor endows material with hierarchical pores and a highly conductive network, which significantly increases the specific surface area and active sites and provides a fast electron transport channel for electrochemical reactions. Moreover, the synergistic effect of MoS₂/MoO₂ optimizes the ion transport pathway and further enhances the electrocatalytic performance. Experimental results show that the electrode exhibites excellent performance for the simultaneous detection of DA and UA. The linear range for DA detection is 0.5–35 µM with a limit of detection (LOD) of 0.038 µM (S/N = 3), while UA shows a two-segment linear response with linear ranges of 1–20 µM and 20–110 µM, respectively, and a LOD of 0.245 µM (S/N = 3). This electrode is capable of realizing the simultaneous detection of DA and UA in human serum, showing a broad application prospect in the field of biosensing.

Janus kinase inhibitors (JAKis) represent a class of drugs that treat inflammatory and autoimmune diseases by blocking Janus kinase (JAK) enzymes. Monitoring of precise drug concentration ensures therapeutic effect while minimizing the risk of toxicity. In parallel to conventional methods based on high performance liquid chromatography, liquid chromatography − mass spectrometric or spectrometric methods, sensitive electrochemical methods for the detection of JAKis have been developed in very recent years. The procedures utilize conventional bare glassy carbon electrode or boron-doped diamond electrode and, particularly, chemically modified electrodes incorporating nanomaterials and their composites as powerful catalysts as well as imprinted polymers. The linear concentration ranges and limits of detection achieve very low 10^− 9 M to 10^− 12 M (µg to ng/mL) values, matching clinically relevant drug levels and are applied to analysis of biological matrices and pharmaceutical products. In this study, the concentration ranges obtained for individual JAKis are presented and compared with those of conventional methods. The manuscript covers the years 2022 to 2025 highlighting the JAKis electrochemical detection as a new topic. The paper aims to address both current trends and future potential in the development of novel sensors and procedures for the JAK inhibitors detection directed to a real-time point-of-care analysis enabling personalized therapeutic drug monitoring. Advantages and disadvantages of electrochemical approaches for the JAKis assay in clinical settings are critically evaluated. To facilitate the development of more reliable, robust and clinically applicable electrochemical methods, a few recommendations that future studies should follow are proposed.

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A multi-walled carbon nanotube - poly (allylamine hydrochloride acid)/platinum nanoparticle (MWCNT-PAH/PtNP) biosensor for phosphorylated Tau-217 (pTau-217) detection and validated using Alzheimer’s disease (AD) plasma samples is described. Morphological characterization confirmed successful deposition of MWCNT-PAH/PtNP, which enhanced the sensor’s surface height range (bare sensor |∆| = 2.2 μm vs. modified sensor |∆| = 5.7 μm) and electrochemical properties. The sensor achieved a detection limit of 9.85 pg/mL by cyclic voltammetry (CV) and 3.83 pg/mL by chronoamperometry (CA), and could detect pTau-217 in the presence of interfering molecules and in complex protein-rich matrices such as fetal bovine serum (FBS). When validated on clinical samples, the sensor could distinguish AD from cognitive normal (CN ) samples more effectively than ELISA (AUC_CV: 90.75%; AUC_CA: 87.13%; AUC_ELISA: 52.52%). Subgroup analysis revealed that sensor output primarily reflected disease status, with minimal confounding effects from demographic or social factors. However, a key limitation is that current intensity cannot be directly converted into plasma pTau-217 concentration, restricting the sensor to qualitative AD screening rather than precise quantification. Taken together, this biosensor holds great potential as a cost-effective tool for distinguishing AD and CN plasma samples, with promising prospects for on-site application.

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Cu-metal organic framework (MOF) derived porous carbon (Cu/Cu₂O@C₇₀₀) derived from Cu-based MOF was prepared by one-step pyrolysis, and then used together with nitrogen-doped longan shell carbon (NCs) to establish a new electrochemical sensor for the rapid detection of enrofloxacin (ENR) by differential pulse voltammetry. The materials and the preparation process of electrochemical sensor were characterized. Results have shown that Cu/Cu₂O@C₇₀₀ exhibited abundant porous structures, high surface area, and numerous active sites, which significantly improved response sensitivity. NCs is a porous carbon material which possess high specific surface area and make the diffusion and transport of electrolyte ions easier. Under optimal conditions, the peak current of ENR exhibits favorable linear relationships with the concentration within a range 0.1–1000 ng mL^− 1, and the detection limit is 7.73 × 10^− 3 ng mL⁻¹ (S/N = 3). The sensor has good selectivity, stability and repeatability, and good recovery (93.90 ~ 104.0%, RSD<4%) for the detection of ENR in fresh fish and shrimp. Compared with LC-MS/MS, it also shows competitive accuracy, which is of great significance in ensuring the safety of aquatic products.

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