Microchimica Acta最新文献

Ferroptosis is a recently characterized, iron-dependent modality of regulated cell death that precipitates organ injury by derailing cellular redox homeostasis and can serve as an indicator of hepatic injury severity. Yet studies linking ferroptosis to liver pathology face two major constraints: (1) fluorescent probes that use iron ions as the analyte suffer interference from specific reaction chemistries, resulting in low sensitivity and poor physiological stability; and (2) the therapeutic promise of modulating ferroptosis in liver injury remains underexplored. To overcome these barriers, this study introduces two non–iron-based biomarkers—lipid droplet polarity and hypochlorous acid-as alternative analytical targets, thereby avoiding the limitations imposed by iron-specific reactions. Accordingly, we engineered NIR-MZY, a dual-responsive probe capable of simultaneously monitoring lipid droplet polarity and hypochlorous acid, thereby assessing the potential of ferroptosis-targeted strategies for the treatment of liver injury. As expected, we tracked dynamic changes in lipid droplet polarity and hypochlorous acid (HOCl) during drug-induced liver injury and visualized their modulation in cellular and zebrafish models under ferroptosis induction and inhibition. These results indicate that manipulating ferroptosis attenuates hepatic damage and substantiate its viability as a therapeutic target. Thus, NIR-MZY emerges as a convenient, sensitive imaging modality that enables precise diagnosis and intervention in ferroptosis-driven liver injury.

A label-free liquid-crystal aptasensor is reported that transduces florfenicol (FFC)–aptamer binding into optical responses. Nematic 4′-pentyl-4-biphenylcarbonitrile was UV-oxidized to 4-cyano-4′-biphenylcarboxylic acid, whose carboxyl groups enabled coupling of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide to an amino-terminated complementary oligonucleotide dispersed in the liquid-crystal phase. In FFC-free samples, the aptamer tail hybridized with the immobilized receptor, disrupting homeotropic anchoring and yielding a bright planar texture, whereas FFC binding suppressed hybridization, preserving a dark texture. The percentage brightness values derived from polarized optical microscope images decreased linearly with FFC level within 0.2–80 ng mL⁻¹, with a limit of detection of 0.12 ng mL⁻¹. The sensor also showed good discrimination against co-residual veterinary drugs and metabolites relevant to food matrices. Sensor applicability to real matrices was quantified using QuEChERS extracts of milk and eggs diluted 10× with phosphate-buffered saline and spiked with FFC; the sensor achieved recovery levels within the validation limits and equivalent results to those of high-performance liquid chromatography. The proposed aptasensor stabilizes within ~ 20 min, requires no labels or complex instrumentation, and can be readily adapted to other small-molecule residues by swapping the aptamer.

The anode electrocatalyst for direct fuel cells are confined by achieving an optimal balance between the reduced cost, enhanced activity, and favourable durability of electrocatalyst. This work adopted a multi-dimensional optimization strategy to resolved the above challenge. A new hollow hydrothermal carbon (HTC) was developed for the first time, offering a more facile and environmentally friendly preparation process compared to conventional carrier materials. CuPt nano-alloy with enhanced electrocatalytic activity was decorated on hollow HTC nanospheres. The CuPt nano-alloy not only effectively reduced the Pt usage rate but also weakened the adsorption of reaction intermediates (such as CO_ads), thereby alleviating the rapid degradation of electrocatalytic activity. The hollow HTC structure increases the contact area between the electrocatalyst and the reactants, while simultaneously shortening the diffusion path for the reaction products. It is indicated that the C/CuPt-6%NS demonstrated a superior performance in the formic acid, formaldehyde, and methanol electrocatalytic oxidation. Compared to commercial Pt/C, C/CuPt-6%NS exhibited enhancement factors of 8.46 and 6.11 in the electrocatalytic oxidation of formic acid and formaldehyde, respectively. In the electrocatalytic methanol oxidation, the mass activity of C/CuPt-6%NS toward is 9.75 times higher than that of commercial Pt/C. Moreover, after 3600 s of continuous electrocatalytic methanol oxidation, the massic activity of C/CuPt-6%NS remained as high as 26,466 µA/mg_Pt, which was approximately 176.44 times higher than that of the commercial Pt/C. Benefiting from its superior durability and enhanced electrocatalytic oxidation activity, the C/CuPt-6%NS has been verified to be a promising electrochemical sensor material in formaldehyde and formic acid detection.

Characterising the fate of nanoparticles in the gastrointestinal tract as well as their uptake and crossing through the intestinal epithelium is essential for nanomaterials used in food-related applications. In chemico, in vitro and in vivo studies allow to simulate the human digestion process, assess transport across the intestinal barrier, and characterise the absorption and biodistribution of nanoparticles after oral exposure, respectively. However, these studies pose substantial analytical challenges. These include selecting the appropriate technique for the different physicochemical properties to be measured, dealing with complex sample matrices, distinguishing the particles of interest from any other interfering nanozised entity, discriminating the particulate fraction from any possible soluble (ionic or molecular) counterpart. The present review addresses these challenges by first providing an overview of the measurement techniques available for physicochemical characterisation and then examining the analytical strategies applied in the existing studies, from sample preparation protocols to the analytical measurement approaches, focusing on the information delivered, advantages and limitations. Emphasis is given to the combination of complementary analytical techniques addressing both the mass concentration and the size distribution of the particulate fraction, with special focus on mass spectrometry (MS)- and electron microscopy (EM)-based techniques. Crucial aspects such as dispersion protocols, analytical artefacts, development of approaches for complex and less studied organic nanomaterials are addressed. Based on the provided critical overview, a comprehensive multi-method analytical strategy to deal with these demanding physicochemical measurements is outlined.

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The functional design of carbon dots (CDs) is the key to enabling their practical biological applications. In this study, mitochondria-targeted carbon dots (M-CDs) with a large Stokes shift were successfully synthesized using Rhodamine B, o-phenylenediamine and pentyltriphenylphosphonium bromide as precursors through a one-step solvothermal method. Stable fluorescence performance of M-CDs was demonstrated in environments containing various ions (except Fe³⁺), amino acids, as well as under different pH, polarity, and viscosity conditions, guaranteeing their reliable application in complex biological environments. M-CDs exhibited highly efficient and specific mitochondrial targeting through a “synergistic electrostatic-hydrophobic targeting mechanism” as evidenced by a co-localization coefficient of 0.91 with a commercial mitochondrial probe. Furthermore, M-CDs were successfully employed to monitor mitochondrial morphological changes in real-time during hydrogen peroxide-induced oxidative stress and CCCP-triggered mitophagy. In addition, it was found that M-CDs exhibited unexpected specific fluorescence response to Fe³⁺, with a static quenching mechanism and a detection limit of 0.65 µM. Finally, M-CDs served as a sensitive indicator of intracellular iron overload, offering key evidence for the occurrence of ferroptosis. This study not only developed a highly stable multifunctional fluorescent carbon dot but also revealed the synergistic effect of the lipophilicity of long-chain alkyl groups and electrostatic guidance of TPP cations in enhancing organelle targeting, providing new ideas for the design of organelle imaging probes for complex biological environments.

Sample preparation typically involves multiple steps to create conditions for separating analytes from the sample matrix. These steps involve the preparation of reagents and materials, their addition into the sample, mixing by external energy input, and timing of each step. All these steps increase analysis time, reduce sample throughput, and require benchtop laboratory equipment and trained personnel. In this work, we report layered effervescent tablets to simplify multistep sample preparation. The tablets consist of layers that dissolve sequentially at a controlled rate, releasing stored, pre-quantified reagents at specific time intervals. As a proof-of-concept demonstration, we designed tablets for the extraction of copper ions, as model analyte, from aqueous solutions. The tablets autonomously perform a series of steps that involve adjustment of pH, dissolution and dispersion of a chelating agent, incubation, mixing and extraction of the metal chelates in a magnetic sorbent by the action of effervescence. The preliminary analytical application of the method to the determination of copper in environmental samples revealed analytical features, which are comparable to standard laboratory practices (recoveries > 80%, RSD < 8%). In this manner it is demonstrated that layered effervescent tablets can be a promising tool for simplifying multistep sample preparation by reducing reliance on human and technical resources and allowing extractions to be performed with minimal intervention and basic infrastructure.

A novel electrochemical sensor for the determination of glyphosate (GLY) has been developed. It is based on a nanocomposite of zinc-based zeolitic imidazolate framework-67 and exfoliated montmorillonite (Zn-ZIF-67/Exf. MMt). The composite was synthesized by a hydrothermal method and characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and surface area analysis (BET). Incorporated into a modified graphite paste sensor (MGPS), the material provided high conductivity, large electroactive surface area (0.68 cm²), and low resistivity (75.0 Ω). Using square wave adsorptive cathodic stripping voltammetry (SW-AdCSV), the optimized sensor, containing 1.0% (Zn-ZIF-67/0.5 Exf. MMt) modified graphite paste sensor (MGPS), showed excellent electrochemical performance with a high electroactive surface area (0.68 cm²), and low resistivity (75.0 Ω). Under standard conditions, the sensor achieved a low detection limit of 0.009 nM (linearity range: 0.03-1.0 nM), and 0.015 nM (linearity range: 0.05–1.2 nM) in bulk, and spiked soil, respectively. This sensor offers a practical and highly sensitive tool for early detection of glyphosate, supporting environmental safety and sustainable agriculture.

An electrochemical (EC) molecularly imprinted polymer (MIP) sensor for therapeutic drug monitoring of olanzapine (OLZ) has been developed. A “rime-like” gold-platinum nanostructured film (Au-Pt NF) was fabricated on a screen-printed carbon electrode (SPCE) via an one-step hydrogen bubble dynamic template (HBDT) method, followed by electropolymerization of a polyaniline-based MIP. The Au-Pt NF/SPCE served as an ideal three-dimensional conductive substrate with a large active area and enhanced electron-transfer capability, endowing the specific MIP sensor with high sensitivity. Using [Fe(CN)₆]^3−/4− as a redox probe, the sensor quantified OLZ by the decrease in differential pulse voltammetry current caused by target binding. It exhibited two linear ranges (0.005–0.4 µM and 0.4–10 µM) with a detection limit of 0.94 nM, and demonstrated high selectivity, reproducibility, and stability. The sensor achieved recoveries of 96.7–102.7% for OLZ in tablets, urine, and whole blood. This work provides a reliable, all-EC sensing platform with strong potential for rapid OLZ monitoring in clinical settings.

Foodborne pathogens such as Escherichia coli (E. Coli), Salmonella, and Listeria monocytogenes continue to pose a major potential threat to global public health and therefore rapid, accurate, and field-deployable detection methods are still extremely desirable. This review describes cutting-edge examples of advanced biosensing platforms for the strategy of detecting these priority pathogens, focusing on clinical detection and highlighting electrochemical, optical, and microfluidic sensing modalities. This has been enabled by recent advances in functional nanomaterials, molecular recognition elements (including aptamers and nanozymes), and surface engineering strategies rendering sensors much ‘smarter’/improved in terms of sensitivity, specificity, and behaviour towards complex food matrices. However blending these biosensors with artificial intelligence (AI) and Machine Learning (ML) enabled intelligent pattern recognition, real-time analytics, and multiplexing at high-speed, turning traditional detection systems into smart diagnostic devices. We critically review recent case studies in light of biosensor design, signal transduction mechanisms, models of AI, performance validation, and applicability in different food environments. The principal challenges are identified which include matrix interference, instability of biorecognition elements, limitations in scalability, and the need for regulatory standardization. We discuss these with associated mitigation strategies that are technically sound, including ratiometric sensing, microfluidic pre-treatment techniques, explainable AI, and printable electronics. Forward-looking, we discuss biosensors enabled by being self-powered, biosensor hubs with modular pathogen panels, blockchain incorporation, and standardized validation pipelines. This review offers a prospective view toward enabling intelligent, robust, and regulation-ready biosensing platforms for next-generation food safety monitoring through the bridging of technological innovations with practical implementation.

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