Chinese Journal of Analytical Chemistry最新文献

Targeted delivery of proteins into desired cell groups is crucial for disease therapy and cellular functionalization. However, current delivery methods face severe side effects and off-target problems, making it difficult to achieve cell-targeted protein delivery. Herein, we developed a user-friendly membrane fusion liposome for cancer cell-targeted protein delivery. Phosphorothioated DNA-mediated membrane fusion was employed as an efficient transmembrane delivery approach. The phosphorothioated DNA was capped with the AS1411 aptamer, which specifically recognizes nucleolar proteins on the cancer cell membrane, enabling a controllable delivery of proteins into targeted cancer cells. This delivery system exhibited commendable biocompatibility and targeted delivery ability, thereby realizing highly effective cancer cell inhibition in vitro. The in vivo results further suggested that the membrane protein-responsive membrane fusion delivery system offers a new avenue for highly biocompatible and targeted protein delivery.

Highly selective, sensitive, and fast hydrogen sensing technology is becoming increasingly important in the processes of production, transportation, and usage of hydrogen energy. Field-effect transistor (FET) is the basic element of modern IC. When serving as a gas sensor, FET poses advantages of small size, high sensitivity, and low power consumption. This article reviews the latest developments in FET hydrogen sensors based on channel materials from traditional silicon, III-V compound semiconductors to novel channel materials carbon nanotubes, graphene, and two-dimensional black phosphorus. Firstly, the structure of FET sensors was investigated. Then the sensitive materials severing as gate were reviewed and efforts to improve the performance was summarized. Then, we discuss the sensitive materials that are currently available, with a focus on the interaction mechanisms between hydrogen and the sensitive materials. Lastly, methods to enhance sensor performance by modifying the physical and chemical properties of the sensitive materials are presented. Finally, the article provides an outlook on the future development of FET type hydrogen gas sensing.

Simultaneous and rapid detection of various mycotoxins in food holds significant practical importance in the field of food processing and safety. In this study, a fluorescent aptasensor based on functionalized graphene oxide (FGO) is developed for simultaneous detection of aflatoxin B₁ (AFB₁) and aflatoxin M₁ (AFM₁). The two aptamers specific to AFB₁ and AFM₁ are labeled with Cy3 and Cy5 respectively. Both the aptamers can be adsorbed onto the surface of FGO through π-π stacking, resulting in fluorescence resonance energy transfer (FRET) between the fluorophore and FGO. The absence of target leads to quenching of fluorescence while presence of either aflatoxin causes interaction between corresponding aptamer and target, leading to release from FGO surface thereby turning on fluorescence signal. The limit of detection (LOD) for AFB₁ is determined as 8.7 pg/mL whereas for AFM₁ it is found to be 20.1 pg/mL, demonstrating fast and sensitive detection capability using this approach. Furthermore, the aptasensor exhibits good specificity and selectivity even under influence from other common interfering toxins. With its simplicity in operation and portability features, this sensor has potential applications for establishing sensitive and portable on-site detection methods for various mycotoxins.

Protein-small molecule interactions play an important role in the life activities of organisms. Since protein/small molecule interactions are important for elucidating the diverse uses and their mechanisms in the fields of biological life multiplicity, disease cure, drug development, etc., methods to accurately detect protein/small molecule interactions have attracted much attention. This paper reviews the recent advances in interaction detection methods based on optical, thermodynamic, chromatographic and other principles. The structural types of small molecules for which the methods are mainly suitable and the principles of method selection are discussed, and the prospects for the combined application of different methods in the field of complex small molecule drugs are also envisaged.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic disease with an unclear etiology and no effective treatment. This study aims to elucidate the pathogenic mechanism networks involving multiple targets and pathways in IPF. Extracts and metabolites of Astragali Radix (AR) and Angelicae Sinensis Radix (ASR), two well-known traditional Chinese medicines, have demonstrated therapeutic effects on IPF. However, the underlying mechanisms of AR and ASR remain unclear. Utilizing network pharmacology analysis, the disease targets associated with IPF were obtained from the GeneCards database and Online Mendelian Inheritance in Man (OMIM) database. Targets of AR and ASR were identified using the Traditional Chinese Medicine (TCM) Systems Pharmacology Database and Analysis Platform and Swiss Target Prediction. A proteinprotein interaction (PPI) network was subsequently constructed and analyzed using the STRING database and Cytoscape software. Gene ontology enrichment (GO) analysis and kyoto encyclopedia of genes and genomes (KEGG) analysis were conducted using DAVID. Additionally, a component-target-pathway network was employed to identify the main active components, and molecular docking was performed between these components and proteins encoded by key targets. Finally, in vitro studies were conducted based on network pharmacology. A total of 260 common targets between IPF and drug targets were identified and included in the PPI network, in which TNF, IL-6, STAT3, AKT1, VEGFA, SRC, EGFR, INS, JUN, and IL1B were predicted as key targets. These 260 targets were enriched in the PI3K-AKT signaling pathway, HIF-1 signaling pathway, TNF signaling pathway, MAPK signaling pathway, FOXO signaling pathway, and Pathways in cancer. Docking scores ranged from –4.1 to –9.5 kcal/mol, indicating a strong binding affinity between the main active compounds and key targets. In vitro studies have indeed shown that Quercetin and Magnolol can alleviate the expression of epithelial-mesenchymal transition in the A549 cells caused by IL-6. The treatment with AR and ASR resulted in a reduction of mRNA levels for key targets HIF-1α and α-SAM. Additionally, the protein expression levels of P-JAK2/ JAK2, P-STAT3/ STAT3, and α-SMA/ β-Actin were also reduced. These results support the therapeutic potential of AR and ASR in ameliorating pulmonary fibrosis and provide insight into the molecular mechanisms involved in their therapeutic effects.

The green chemistry method for analyzing changes in the concentration of substances during a reaction process is an energy-saving and interesting experimental process. In this paper, the performance of electrolysis of methylene blue (MB) in NaCl electrolyte was studied using a smartphone-based paper microzones method (PMZs), and paper microzone platform was made by discarded label stickers. The linear range spanned from 1.25 to 15 mg/L for the concentration-absorbance correspondence measured via spectrophotometry, and from 1.25 to 17.5 mg/L for the concentration-R-value correspondence measured via the PMZs method. The findings revealed that the limit of detection (LOD) value of the PMZs method was 0.494 mg/L, and the limit of quantification (LOQ) value was 1.497 mg/L. Moreover, the accuracy ranking of the measured MB electrolytic change process across different channels was as follows: Red>Grey>Green>Blue. PMZs method also showed well reliability in measuring actual dye polluted wastewater. The results demonstrate the sensitivity and precision of the PMZs method, as indicated by the low LOD and LOQ values. Additionally, the accuracy ranking provides valuable insight into the performance of the method across different color channels, shedding light on the potential applications and limitations of the PMZs technique in color-based electrochemical analyses. The electrolysis reaction led to a red-shift in the absorption characteristics of MB in NaCl electrolyte, resulting in a notable change in its light absorption properties. This information is crucial for researchers and practitioners seeking to employ the PMZs method for accurate and reliable color measurements in various scientific and industrial settings.

Water pollution is currently a major problem worldwide. Given its detrimental effects on health, Hg(II) is considered an extremely hazardous heavy metal contaminant, even at low doses. Heterocyclic compounds have been thoroughly evaluated as the chemosensor agents for Hg(II) detection. However, they suffer from poor sensitivity. In this study, we prepared two fluorescence chemosensor agents from vanillin via several steps, i.e., etherification, Claisen–Schmidt, and cyclocondensation reactions to yield N-phenyl- and N-pyridine-pyrazoline compounds. Products characterization was accomplished via spectroscopic techniques. Chalcone, N-phenyl-, and N-pyridine-pyrazoline derivatives were successfully obtained at 87.04%, 90.91%, and 91.73% yields, with limits of detection of 156,840, 65.810, and 161.011 nM, respectively. These results show that the conversion of chalcone to pyrazoline structure improved the sensitivity for Hg(II) detection at the nanomolar level, which is 2384 times lower than that for chalcone. Further spectroscopic investigations through Job's plot, Fourier-transform infrared spectroscopy, and proton-nuclear magnetic resonance analyses revealed that Hg(II) ions were chelated with two nitrogen atoms of pyrazoline. Thus, this phenomenon can explain the considerable sensitivity enhancement for Hg(II) detection. N-Phenyl-pyrazoline is the more sensitive chemosensor to Hg(II) compared with N-pyridine-pyrazoline because the more nitrogen groups in the binding site, the less selective and sensitive the compound. This finding is also supported by the higher binding constant value of N-phenyl-pyrazoline (9.416 × 10² mol⁻¹) than N-pyridine-pyrazoline (1.771 × 10² mol⁻¹). Furthermore, N-phenyl-pyrazoline can be applied in the direct quantification of Hg(II) in tap and groundwater samples with a validity parameter in a range of 80.97%–103.54%.

To elucidate the concentrations of heavy metal elements in commercially available electronic cigarettes and improve quality assessment. Inductively coupled plasma-mass spectrometry (ICP-MS) coupled to chemometrics was used to determine the concentrations of Cr, Ni, As, Cd, Sn, Sb, Hg, and Pb in the e-liquids and aerosols derived from 32 electronic cigarettes sold commercially under six brand names. The e-liquids contained: 4.858 to 274.658 (Cr), 17.292 to 3068.375 (Ni), 3.217 to 29.867 (As), 0.225 to 24.717 (Cd), 0.783 to 17.042 (Sn), 0.658 to 36.033 (Sb), 0.658 to 187.592 (Hg), and 2.458 to 17.417 (Pb) ng g⁻¹. The aerosol samples contained: 276.075 to 3333.175 (Cr), 72.908 to 1150.183 (Ni), 4.567 to 86.958 (As), 0.400 to 12.842 (Cd), 1.092 to 32.142 (Sn), 0.976 to 10.633 (Sb), 3.483 to 234.708 (Hg), 27.833 to 849.100 (Pb) ng 100 puffs⁻¹. The recovery of heavy metals ranged from 99.1% to 112.4% in the e-liquids and from 87.3% to 116.6% in the aerosols, with RSD values below 10%. Hierarchical cluster analysis grouped the e-liquids into eight clusters, and the aerosols into five, indicating differences between products within brands and between different brands. Orthogonal partial least squares discriminant analysis coupled with variable importance in projection (VIP > 1) identified As and Sb as the primary heavy metals causing differences between the e-liquids, while differences between the aerosols were caused by Hg, As, Pb, Cd, and Cr. The use of chemometric methods yields a greater depth of information that will support improvements to the quality control of e-cigarette products and the assessment of their potential risk to human health.

In this study, Co-Ni nanomaterials were in situ synthesized on carbon fiber paper substrates, termed Co-Ni paper. Scanning electron microscopy characterization demonstrates fabricated flake-like Co-Ni nanocomposites uniformly distribute on carbon fibers, forming three-dimensional continuous network structure. The fabricated sample is determined to be a mixture of Co, Ni and C elements according to energy-dispersive X-ray spectrometer analysis. Without any pretreatments, Co-Ni paper exhibits excellent electro-oxidation capabilities towards H₂O₂, such as an excellent detecting performance in a wide linear range of 0‒11.5 mM of H₂O₂, fast amperometric responses within 1 s, and a low detection limit of 2.53 μM. Along with these intriguing properties, the in situ-synthesized Co-Ni paper has a good anti-interference towards Na₂SO₄, ZnCl₂, glucose and NaCl during H₂O₂ detection. Moreover, the H₂O₂ electro-chemical sensor on Co-Ni paper also possesses excellent reproducibility, long-term stability and high mechanical stability. This Co-Ni-paper-based sensor is effective to determine H₂O₂ in blood samples, thus it is promising for electrochemical H₂O₂ sensing.

Using terephthalic acid (BDC) as the organic ligand and zirconium chloride (ZrCl₄) as the metal source, a lanthanide metal-organic framework (Tb/Zr-UiO-66) with excellent luminescence properties was successfully prepared by introducing the lanthanide ion Tb³⁺ in situ through a simple one-pot hydrothermal reaction, which was designed as an optical biosensor for 2-thiothiazolidine-4-carboxylic acid (TTCA), the urinary biomarker of human exposure to carbon disulfide (CS₂). The fabricated Tb/Zr-UiO-66 exhibits high chemical and luminescent stability, making it competent for recognizing TTCA in aqueous environments. Significantly, its luminescence intensity change shows a good linearity relationship with the concentration of TTCA in the range of 0–110 μM, with a limit of detection (LOD) as low as 0.14 μM. Meanwhile, this sensor exhibits good selectivity and anti-interference ability towards TTCA among the various coexisting components in urine (Na⁺, K⁺, NH₄⁺, SO₄²⁻, Cl ⁻, creatine, creatinine, glucose, urea, etc.), and can quickly respond to TTCA within 2 min. The analysis results of powder X-ray diffraction (PXRD), fluorescence lifetime and ultraviolet–visible (UV–vis) spectrum demonstrate that the sensing mechanism can be ascribed to the competition absorption effect between TCAA and Tb/Zr-UiO-66. This biosensor with simple synthesis, stable framework, high sensitivity and selectivity, and rapid response has potential to become a powerful tool for diagnosing diseases associated with CS₂ exposure.