Microchimica Acta最新文献

ZIF-8-core/Au-shell (ZIF-8@Au) nanoparticles were fabricated through a two-step strategy involving thiol-modification of ZIF-8 substrates and subsequent Au shell growth via seed-mediated approach, and the ZIF-8@Au nanoparticles were applied to the screening of clostridium difficile infection (CDI). Through regulating dosage of thiol-modifier, we established a surface functionalization protocol that introduced tunable thiol groups onto ZIF-8 particles while preserving their pristine morphology and crystallinity. Subsequent refinement of Au coating parameters enabled the construction of ZIF-8@Au core–shell nanostructures via seed-mediated growth. The resulting ZIF-8@Au nanoparticles were successfully applied to detect biomarkers of CDI, including toxin A, toxin B, and glutamate dehydrogenase (GDH), with sensitivities of 7 pg/mL, 115 pg/mL, and 27 pg/mL, respectively. These results demonstrate the promising potential of this nanoparticle-based platform for lateral flow assays.

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Acute kidney injury can cause changes in fluid glucose levels, such as blood, sweat, or tears. However, the skin of vulnerable populations, such as premature infants, is extremely fragile and cannot withstand frequent needle-based blood sampling. Detecting glucose in skin sweat provides a non-invasive new approach. This study utilizes laser-induced graphitization technology and secondary modification of electrodes to efficiently fabricate an enzymatic wearable glucose sensor patch on a flexible substrate on a large scale and at a low cost. Experiments show that the sensor exhibits good sensitivity (1.71 µA/mM) within a glucose concentration range < 10 mM. Moreover, it is not affected by other interfering substances in sweat (potassium chloride, sodium chloride, urea, ascorbic acid, etc.). Additionally, by integrating a smart adhesive with switchable adhesion on the patch surface, strong adhesion at body temperature (35 °C, 82.25 N/m) and on-demand removal under mild cooling were achieved (20 °C, 10.13 N/m), effectively avoiding potential skin damage caused by device detachment. This work provides new insights into the efficient and low-cost fabrication of comfortable wearable glucose sweat sensors.

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AuNFs (gold nanoflowers) are widely applied in the field of biosensing; their unique morphological characteristics and high specific surface area enable them to provide a large number of active sites, thereby enhancing the efficiency of catalytic reactions. These features make AuNFs a promising material for improving the performance of loop-mediated isothermal amplification (LAMP). Firstly, the reduction of 4-NP catalyzed by nano-gold (NG) with different morphologies showed that AuNFs made the yellow solution almost transparent in 4 min, similar to AuNPs (gold nanoparticles), with higher catalytic efficiency compared to AuNRs (gold nanorods) (> 8 min). The incorporation of AuNFs increased the activity of Bst DNA polymerase, and the kinetic parameters showed a V_max/K_m of 0.021, which was higher than that of AuNPs (0.015), AuNRs (0.013), and the LAMP system without NGs (0.013). Moreover, at ambient temperature, the UV–vis intensity of the characteristic peak indicates that the loading capacity of ssDNA is approximately 1.6 × 10⁵ per AuNF, and when the temperature rises to 65 °C, ssDNA is almost completely released from the AuNFs. This mechanism may be beneficial for suppressing the generation of non-specific amplification. Dynamic light scattering (DLS) and circular dichronism (CD) results indicate that AuNFs alter the α-helix structure upon binding with Bst, potentially thereby enhancing enzyme activity. LAMP amplification was performed at different temperatures, and the results illustrate that the Tt values of AuNFs@LAMP were lower than those of AuNRs@LAMP (P < 0.0001), AuNPs@LAMP (P = 0.0082), and classical LAMP (P < 0.0001) at 40, 45, 50, 55, and 60 ℃. Thus, we proposed the AuNFs@LAMP (AuNF-mediated LAMP) method and applied it to the detection of AHSV (African horse sickness virus) standard plasmid sample and spiked dust sample with a sensitivity as low as 10 copies/μL. Intra-day, inter-day, and intra-batch precision showed RSD < 5%, with RSD ranging from 2.51 to 8.75% across low, medium, and high plasmid template concentrations, respectively. Moreover, the specific AuNFs@LAMP system inhibits non-specific amplification in negative samples and in samples containing other equine virus plasmids (WNV, JEV, VSV, NIV, EEEV, WEEV).

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A mitochondria-targeted NIR ratiometric and colorimetric fluorescent probe with large Stokes shift for Hg²⁺ sensing was rationally designed and synthesized. The fluorescence probe exhibited the maximum fluorescence emission peak at 721 nm (NIR region) and absorption peak at 558 nm. Upon addition of Hg²⁺, the maximum fluorescence emission and absorption peaks underwent significant blue shifts to 578 nm and 448 nm respectively. Concurrently, distinct color changes were observed: from purple to orange under 365 nm UV light and from pale purple to pale yellow under daylight. These changes arise from Hg²⁺-triggered deselenation-hydrolysis of the diphenylphosphinoselenoate moiety in the fluorescence probe, which involves cleavage of the P-O bond and formation of intermediate A containing phenolic hydroxyl group, subsequently self-immolative reaction of p-hydroxybenzyl moiety in the intermediate A by 1,6-elimination to release a fluorophore. The fluorescence probe demonstrated excellent sensing performance for Hg²⁺, characterized by a large Stokes shift (163 nm), rapid response (6 min), high sensitivity (LOD of 37.3 nM), and outstanding selectivity over other metal ions. Furthermore, the fluorescence probe was successfully applied to both time-dependent and concentration-dependent ratiometric fluorescence imaging of intracellular Hg²⁺ and demonstrated specific mitochondrial targeting. Notably, this work proposes for the first time a novel design strategy involving the modification of diphenylphosphinoselenoate onto the N atom of quinoline to construct Hg²⁺-responsive probes.

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A novel gas sensor based on CH₃NH₃Pb(I_1 − xBr_x)₃ (MAPb(I_1 − xBr_x)₃) perovskite materials was prepared to achieve the detection of NH₃ gas at room temperature of 25℃. The TiO₂ nanorod arrays were first synthesized on FTO glass through the hydrothermal method, and then MAPb(I_1 − xBr_x)₃ perovskite films were fabricated using a one-step spin-coating technique. Following Br doping, the morphology of the MAPb(I_1 − xBr_x)₃ perovskite film transitions from a dendritic to a tubular structure, leading to enhanced film quality and crystallinity. The gas-sensing test results demonstrate that the response of the MAPb(I_0.85Br_0.15)₃ sensor to 100 ppm ammonia is 36.8%, which is 1.9 times higher than that of the MAPbI₃ sensor at room temperature. The adsorption energy of MAPb(I_1 − xBr_x)₃ on ammonia was calculated through first-principles calculations. The results indicated that Br ions doping could enhance the adsorption capacity of MAPb(I_1 − xBr_x)₃ to ammonia molecules. The adsorption of ammonia by the MAPb(I_1 − xBr_x)₃ sensor is primarily attributed to ammonia molecules entering the octahedral center of the perovskite crystal, where they replace the MA⁺ cations and form NH₄Pb(I_1 − xBr_x)₃·MA intermediate compounds through a weak interaction akin to a chemical bond.

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Ferroelectric materials, due to their spontaneous polarization, can enable efficient electron-hole pair separation, which subsequently enhances reactive oxygen species (ROS) production. This has gradually become a significant direction for screening high-performance nanozymes. This work explores the selective peroxidase (POD)-like activity of a classical ferroelectric material, BiFeO₃ nanoparticles (BiFeO₃ NPs), enabling efficient catalytic generation of ROS. Capitalizing on this nanozyme property, a sensitive colorimetric assay for alkaline phosphatase (ALP) detection was developed. BiFeO₃ NPs can catalyze the oxidation of the chromogenic substrate 3,3’,5,5’-tetramethylbenzidine (TMB) by H₂O₂, whereas pyrophosphate (PPi) significantly inhibits this catalytic activity. Conversely, ALP restores the catalytic activity of BiFeO₃ by catalyzing the hydrolysis of PPi. The colorimetric signal generated through this specific inhibition-recovery mechanism enables the sensitive detection of ALP. Under optimal reaction conditions, the developed method demonstrated a linear response range of 0.040 to 1.0 U/L, achieving a detection limit as low as 0.026 U/L with high selectivity and robust anti-interference capability. Additionally, this method was successfully implemented for ALP detection in artificial saliva samples, achieving recoveries of 95.6–102.9% with a relative standard deviation below 5.0%, showcasing its practical potential for detection in complex biological fluids. This research provides new insights into the application of ferroelectric materials in nanozyme applications and offers a reliable technical approach for the efficient detection of ALP.

Mixed-ligand metal organic frameworks have received great attentions as novel sorbents for sample preparation due to their fascinating structures and intriguing functionalities. Here, we report the fabrication of mixed-linker ZIF-8-90 s with tunable properties for effervescent tablet-assisted dispersive solid-phase extraction (ET-DSPE) of polycyclic aromatic hydrocarbons (PAHs) in environmental water before HPLC separation and hydroxyl metabolites of PAHs (OH-PAHs) in urine samples prior to LC-MS/MS. ZIF-8-90 s based effervescent tablets possessed the high affinity towards analytes via Zn-O bond and π-π interaction, and afforded a great excluding ability to interfering components from urine samples. ET-DSPE of PAHs from 15 mL water sample with ZIF-8₂₅-90₇₅ gave enhancement factors of 122–155, linear ranges of 4-10⁵ ng/L, detection limits (S/N = 3) of 1–8 ng/L, and recoveries of 81.1%-103%. For the determination of OH-PAHs, the proposed ET-DSPE method using ZIF-8₈₅-90₁₅ allowed direct loading of 4 mL of crude human urine sample and provided the linearity range of 0.004-100 ng/mL, detection limits of 0.001–0.008 ng/mL, and recoveries of 82.1%-104%. In conclusion, ZIF-8-90-based ET-DSPE coupled with HPLC and LC-MS/MS were successfully applied to monitor both PAHs in environmental water and OH-PAHs in urine in a facile, efficient and reliable way.

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Saliva contains low-abundance phosphopeptides carrying important pathological information, but determining them with mass spectrometry is difficult due to matrix interference and low ionization efficiency. A well-designed nano-trapper with multiple affinity sites can help solve this problem. In this study, we developed a new dual Ti-affinity magnetic MXene (dTi-MMX). It combines the natural Ti-OH sites of MXene with additional Ti-O sites from titanium dioxide nanoparticles coated onto magnetic Ti₃C₂Tₓ MXene. This dual Ti-site approach significantly improves phosphopeptide capture, while the magnetic core allows for quick separation. Performance tests showed that dTi-MMX detects as low as 10 fmol‧µL^-1 of β-casein digests and selectively enriches phosphopeptides in mixtures of β-casein and BSA (at a 1:1000 mass ratio). When applied to human saliva, dTi-MMX successfully identified 110 unique phosphopeptides. Gene ontology analysis suggests that these peptides primarily participate in pathways such as salivary secretion and multicellular organismal processes, including several biomarkers associated with diseases, such as CST1 for cancer and LPO/CST3 for Alzheimer disease. This approach offers an effective tool for salivary phosphoproteomics research.

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Colorless ammonia vapor has played a crucial role as an intermediate in various industrial processes. However, exposure to ammonia causes organ damages or even death. In this context, a colorimetric ammonia detector was prepared using an eco-friendly poly(lactic acid)-co-polycaprolactone membrane. Using the scanning electron microscopic (SEM) images, the diameter of the poly(lactic acid)-co-polycaprolactone nanofibers was determined to be 160–305 nm. Betalain (BLN) is a natural spectroscopic probe found in beetroot (Beta vulgaris L.). The betalain dyestuff was immobilized within the nanofibrous membrane using a mordant (potassium aluminum sulfate), resulting in mordant/betalain (M/BLN) coordinated complex nanoparticles. Using transmission electron microscopic (TEM) images, the diameters of M/BLN nanoparticles were monitored in the range 6–22 nm. Exposure to ammonia caused a rapid colorimetric change in the betalain-containing membrane from red to yellow, which was proved by using absorbance spectra and the CIE Lab colorimetric parameters. This color change is attributed to an intramolecular charge delocalization on the BLN molecule. Ammonia caused a hypsochromic behavior in the absorbance spectra from 601 nm to 426 nm, designating an isosbestic wavelength of 491 nm. The poly(lactic acid)-co-polycaprolactone membrane has shown a detection limit of 1-250 ppm NH₃.

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Mycoplasma pneumoniae (M. pneumoniae) is a leading cause of community-acquired pneumonia, especially concerning for young children. Effective management and infection control necessitate rapid, convenient, and user-friendly methods for early diagnosis, including genotype and macrolide resistance monitoring during outbreaks. Current clinical methods are often time-consuming, complex, and lack the capability for simultaneous detection. To address these challenges, we developed a one-pot visual multiplex microfluidic digital polymerase chain reaction (MMDPCR) assay for the simultaneous detection of M. pneumoniae infection, P1 typing, and macrolide resistance, utilizing four special fluorescence probes. The developed multiplex microfluidic digital polymerase chain reaction (MMDPCR) assay provides absolute quantification of clinical samples with a detection time of approximately 1.5 h. The MMDPCR assay demonstrated high specificity and superior sensitivity for M. pneumoniae, with a low detection limit of 10–100 copies and no cross-reactivity with other respiratory pathogens. We validated the assay’s performance using 192 clinical samples collected during the 2023–2024 Beijing epidemic. Results showed a positivity rate of 56.25% and a high prevalence (99%) of the A2063 macrolide resistance mutation. Among positive samples, Type I accounted for 75.9% and Type II for 24.1%, showing 100% concordance with qPCR findings. This novel multiplex detection platform holds immense potential for point-of-care testing of M. pneumoniae, offering a rapid and comprehensive tool for analysing its molecular epidemiological characteristics. Its ability to simultaneously provide information on infection, genotype, and macrolide resistance is crucial for guiding clinicians in the rational use of antibiotics and strengthen public health surveillance efforts.

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