Microchimica Acta最新文献

This study aims to develop an efficient and accurate method for detecting human serum albumin (HSA) in urine using lateral flow immunochromatography analysis (LFIA) and a smartphone-based application (App). First, a LFIA test strip using colloidal gold as the labeling material was developed and optimized. A detecting accessory was designed and produced, including a strip kit that can package the LFIA test strip, and a test cartridge that can mount the smartphone on top of it. Then an App was constructed to automatically identify the concentration of HSA on the test strip using photos taken by smartphone. The detection limit of HSA by the proposed platform is 2 µg/mL, and the quantitative range is 5 ~ 200 µg/mL. The coefficient of variation is less than 18.3% and the accuracy is between 95.3% and 108.0%. Twenty urine samples from patients were tested for HSA by both the intelligent platform and ELISA. Results of the two methods showed good precision and accuracy, with a correlation coefficient of 0.9814. In conclusion, the LFIA strip for HSA is small, portable and low cost. By combining with intelligent analysis, it can be used for self-testing at home or monitoring in the clinic thereby realizing early diagnosis of HSA-related diseases.

A highly sensitive immunochromatographic test strip has been developed based on upconversion nanoparticles (UCNPs) for the quantitative detection of prostate-specific antigen (PSA). UCNPs exhibit distinctive anti-Stokes luminescence properties, enabling near-infrared excitation with visible light emission, which significantly reduces background autoluminescence and enhances signal clarity. The fabricated test strip demonstrated excellent sensitivity, specificity, and reproducibility in PSA detection, offering a promising platform for rapid, point-of-care testing. This approach holds potential for improving prostate cancer screening and real-time disease management in clinical and resource-limited settings.

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A low cost and rapid electrochemical immunosensor for direct screening of L-phenylalanine (L-Phe) using square wave voltammetry (SWV) is presented. Fern-like gold nanostructures were electro-deposited onto a screen-printed electrode (SPE) using chronoamperometry (CA), to enhance sensitivity and surface area. A novel light-driven surface functionalisation process was used to decorate the gold nanostructured SPE with target-specific antibody fragments and develop the L-Phe-specific immunosensor. The selectivity of the sensor was confirmed against tyrosine, tryptophan and D-phenylalanine, thus indicating the sensor’s potential for use at points of care (POC) without interference from structurally related biomolecules. The sensor demonstrated high sensitivity across the full clinical range (120 µM-1200 µM) and excellent linearity within the concentration range 1 µM to 2000 µM (R²= 0.99, LOD = 0.3 µM, LOQ = 1 µM). Quantification of L-Phe in human blood dry spots (DBS) by the new sensor and SWV were in excellent agreement with mass spectroscopy (MS) measurements by 2 independent pathology labs. The sensor was successfully integrated with an ultra-compact potentiostat in a Lab-on-a-Phone assembly for L-Phe screening in DBS, thus demonstrating its potential for use at POC and at home by phenylketonuria (PKU) patients in both remote and rural areas.

Alpha-fetoprotein (AFP) is a critical tumor biomarker associated with various diseases, and its accurate determination is very important for clinical detection. However, the conventional techniques for detecting AFP have drawbacks such as complex sample pretreatment procedures, complicated and time-consuming operations, reliance on expensive and bulky instruments, and the need for skilled professionals, thus limiting their applications. The emergence of aptamers provides a novel and unique probe for establishment of aptasensors, effectively avoiding the aforementioned shortcomings. As a result, the application of aptamers for AFP detection has garnered increasing attention and became one of the research hotspots in recent years. In this review, the progress of aptamer selection against AFP is presented initially. Subsequently, we systematically summarize the latest advancements and trends in optical and electrochemical aptasensors for AFP detection, focusing on known AFP aptamer sequences and methods that use aptamers, such as fluorescence, surface-enhanced Raman scattering (SERS), chemiluminescence (CL), and photoelectrochemistry (PEC). In addition, challenges and future directions in this field are discussed to provide insights for the development of efficient and accurate AFP detection technologies.

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Photocatalytic processes have emerged as powerful signal amplification strategies for electrochemical biosensors by generating reactive radicals under mild conditions. However, the integration of photocatalysis with controlled radical polymerization, such as reversible addition-fragmentation chain transfer (RAFT), remains underexplored. Herein, we report a novel photo-Fenton-mediated RAFT polymerization system based on a heterostructured α-Fe₂O₃/Ti₃C₂T_xMXene, which synergistically bridges photocatalysis and polymer chemistry for biosensing applications. Within this heterostructure, Ti₃C₂T_xMXene serves as a conductive scaffold that promotes charge separation in α-Fe₂O₃ under visible light, accelerating H₂O₂ decomposition to generate abundant hydroxyl radicals (•OH). These radicals initiate and regulate RAFT polymerization, enabling controllable chain growth and amplified electrochemical signals. The developed photo-Fenton-driven RAFT coupling was successfully integrated into a biosensor for microRNA-144 detection, exhibiting a broad linear range (0.01 fM-10 pM) and an ultralow detection limit of 4.44 aM. This work demonstrates a synergistic strategy that connects photocatalysis with controlled radical polymerization, providing a rational design approach for MXene-based hybrid materials toward ultrasensitive biomedical sensing.

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Nitrogen-phosphorus co-doped carbon dots (NP-CDs) were prepared by a one-step hydrothermal method in the presence of triethylenetetramine and phosphoric acid using corn whiskers as a carbon source. A paper-based phosphorescent probe, NP-CDs@matrix@paper, with a room-temperature green phosphorescence afterglow lasting up to 8 s was constructed by using the rigid environment provided by boric acid and urea. Oxytetracycline (OTC) not only enhances the intensity of the phosphorescence of the probe, but also exhibits a dynamic change from yellow phosphorescence to green phosphorescence discernible by the naked eye, which creates a favorable condition for visual detection of OTC. A series of optical properties were investigated to further reveal the interaction mechanism between the probe and OTC. The limit of detection (LOD) of the NP-CDs@matrix@paper probe for OTC is 1.17 µM. The results of sample analysis by using this probe are in high agreement with those obtained by using the national standard method. In this work, a long-life, paper based, color-changing room-temperature phosphorescent probe is developed from biowaste.

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A one-pot method was adopted to prepare polyvinylpyrrolidone (PVP)-modified iron single-atom nanozymes (FeSANs) as signal amplification probes, establishing a rapid and sensitive immunomagnetic bead assay (IMBA) for tetracycline (TC) detection. After optimization, Fe₁₀-ZIF-8@PVP demonstrated the highest oxidase-like and peroxidase-like activities in comparison with Fe₅-ZIF-8@PVP, Fe₂₀-ZIF-8@PVP, and Fe₁₀-ZIF-8. The Michaelis-Menten constants (K_m) for the substrates 3,3’,5,5’-tetramethylbenzidine (TMB) and hydrogen peroxide (H₂O₂) were measured as 0.31 mM and 0.67 mM, respectively. The Fe₁₀-ZIF-8@PVP-assisted IMBAs demonstrated the highest sensitivity, achieving a limit of detection (LOD) as low as 0.196 ng/mL, The sensitivity was enhanced by 48-fold compared to conventional ELISA. Furthermore, the Fe₁₀-ZIF-8@PVP-based IMBA was successfully applied to analyze honey, milk, water and soil samples, yielding recoveries of 97.3% to 109.3%, 92.5% to 105.6%, 89.1% to 108.5% and 93.5% to 107.8%, respectively. Practical analysis of environmental samples revealed TC residues not exceeding regulatory limits, with concentrations above the detection limit found only in three of 32 samples analzed (i.e. 0.43 ng/ml, 1.24 ng/ml, and 0.36 ng/ml in one of the honey, milk and water samples, respectively). This method offers a highly sensitive, rapid, and cost-effective alternative to conventional ELISA for antibiotic detection in food safety.

Leishmaniases are diseases caused by parasites of the genus Leishmania, with clinical symptoms ranging from small skin sores to severe infections in vital organs such as the bone marrow, liver, and spleen. Effective control of leishmaniases depends on the specific and rapid detection of the parasite. Conventional methods, however, face significant limitations, including low sensitivity and specificity, along with high complexity and cost. In this context, biosensor technologies offer a promising solution due to their rapid, sensitive, and selective capabilities. These devices convert biological signals into measurable electrical signals, which enables them to play a crucial role in evaluating new anti-Leishmania drugs and detecting these parasites in clinical samples. This review provides a concise overview of traditional diagnostic methods and critically examines the latest electrochemical and optical biosensing platforms developed for disease detection up to July 2025. The goal is to update the discussion by including advanced biosensor-based approaches and strategies that have the potential to improve real-world effectiveness and address current shortcomings in controlling these diseases.

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Pyrethroid pesticide residues pose a significant global public health challenge, particularly in complex edible fungus matrices where trace, structurally similar pesticides are difficult to distinguish and detect. To address this critical gap, a novel surface-enhanced Raman spectroscopy (SERS) platform is presented integrating “magnetic enrichment, covalent organic framework (COF)-mediated capture, silver shell enhancement, and machine learning (ML)-driven intelligent recognition”. The core innovation lies in the tailored Fe₃O₄@COF@Ag nanocomposite architecture where the magnetic Fe₃O₄ core enables rapid sample separation, the COF intermediate layer provides specific molecular capture, and the Ag shell generates dense SERS “hotspots”, synergistically enhanced by ML algorithms to enable precise discrimination of structurally analogous pesticides. The developed Fe₃O₄@COF@Ag substrate demonstrated exceptional performance, achieving detection limits as low as 5.21 µg/kg for deltamethrin (CF), 6.08 µg/kg for fenvalerate (FV), and 11.6 µg/kg for lambda-cyhalothrin (LCF). The method exhibited outstanding linearity (R² > 0.99) for quantitative analysis and anti-interference capability, with recoveries of 94.36-106.89% in real samples. By integrating ML algorithms, the platform achieved 100% classification accuracy for distinguishing structurally similar pyrethroids. Principal component analysis (PCA) and support vector machine (SVM) models effectively extracted discriminative spectral features, enabling precise identification even at trace concentrations. This work provides a rapid, sensitive, and field-deployable solution for pesticide monitoring, offering significant potential to enhance food safety and public health protection.

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A Cu²⁺-coordination crosslinked two-dimensional photonic crystal hydrogel (PN-2DPCH-Cu²⁺) was constructed, in which a polystyrene two-dimensional photonic crystal (PS-2DPC) was embedded in a Cu²⁺-crosslinked poly(acrylamide˗co˗acrylic acid˗co₋N-vinyl imidazole) hydrogel network. The introduction of Cu²⁺ ions was mainly based on the coordination reaction of Cu²⁺ and N atoms of the imidazole rings on the hydrogel chains. The constructed PN-2DPCH-Cu²⁺ smart photonic hydrogel sensor achieved highly sensitive and simple detection of histidine (His) just using a laser pointer and a ruler. The coordination competition of Cu²⁺ to His and N atoms of the imidazole rings drove the hydrogel’s response. In the presence of His, the PN-2DPCH-Cu²⁺ sensor swells obviously because the stronger coordination between Cu²⁺ ions and histidine compared to imidazole rings removed the coordination-crosslinked Cu²⁺ from the hydrogel, thus decreasing its crosslinking density. The swollen hydrogel increased the microsphere spacing of the embedded PS-2DPC, which can be acquired by measuring the Debye diffraction ring diameter of PS-2DPC. The microsphere spacing increments were linearly changed when the His concentrations were in the ranges 0.01–0.03 µM, 0.05–1 µM and 10–500 µM, and the limit of detection was 9.6 nM. The sensor showed high selectivity to His, good anti-interference and stability, and the response can be achieved in 20 min. The good recoveries and relative standard deviations from determining His contents in milk and beverage using our constructed PN-2DPCH-Cu²⁺ sensor demonstrated its accuracy and reliability. The coordination competition strategy of driving hydrogel to response can extend to develop other analytes sensitive hydrogel sensors by choosing suitable polymerizable monomers and metal ions.

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