Analytical Methods最新文献

Atomic force microscopy (AFM) is widely used for the imaging and characterization of biological cells because of its nanoscale spatial resolution and force resolution. However, in the previous studies, the inability to effectively detect the contractile work of cardiomyocytes and the 3D dynamic expressions of their contraction and relaxation behaviors posed significant challenges. Therefore, this work presents a method for the analysis of the contractile work of a single cardiomyocyte by AFM. Two different contractile work measurement modes of cardiomyocytes are proposed, which are the constant height contact mode and the constant force contact mode. The differences in the contractile work were analyzed in two measurement modes. The changes in the contractile work of a single cardiomyocyte in the two measurement modes were studied, and the accuracies of the two measuring models were verified using ginseng extract. After the action of drugs, the contraction force of cardiomyocytes and the work done by contraction force increased. The experimental results indicated that the detection results of the ginseng water extract acting on the same cardiomyocyte by nanomanipulation technology were consistent with its pharmacological effects. Thus, it is reliable to detect the mechanical properties of cardiomyocytes using the nanomanipulation system. This study provides a new method for measuring the contraction force and contractile work of a single cardiomyocyte.

BK Polyomavirus (BKPyV)-associated nephropathy (BKPyVAN) is a leading cause of kidney transplant graft loss. Although polymerase chain reaction (PCR) is a common technique for quantifying BK Polyomavirus (BKPyV) viral loads, it lacks optimal sensitivity due to variations in sample type and source, DNA extraction techniques, primer and probe sequences, and the BKPyV strain DNA used for standard-curve genotype variance, all of which can affect the results. Studies have shown that bkv-miR-B1-5p and bkv-miR-B1-3p can be suitable candidates for the diagnosis of nephropathy in kidney transplant recipients, especially in the early stages of the disease. This research introduces an innovative electrochemical nanobiosensor that can detect BKPyV-related miRNAs, including bkv-miR-B1-5p and bkv-miR-B1-3p, with high sensitivity in renal transplant patients. By using a biotin-modified molecular beacon (biotin-MB) and gold nanoparticles (AuNP)/silver nanoparticles (AgNP), this sensor is able to detect viral miRNA with unparalleled sensitivity. Using square-wave voltammetry (SWV), the system can detect miRNA targets simultaneously, surpassing the constraints of traditional techniques like PCR. The sensor displays high linearity with detection limits of 0.3 fM for bkv-miR-B1-5p and 3.6 fM for bkv-miR-B1-3p. This technology offers the potential for diagnosing BKPyVAN earlier and more accurately, offering important information to enhance the lifespan of kidney transplants.

Ammonia or biogenic amines released by protein degradation during food spoilage have various ill effects on human health and the environment. Herein, an economical colorimetric bisphenol-based sensor was developed from inexpensive reagents and a simple synthetic method for detecting ammonia and monitoring food spoilage. The slightest addition of NH₃ significantly changed the absorption of BP, which was reflected in the detection limit value for NH₃ (7.89 × 10⁻⁷ M). The film-based sensor developed by immobilizing BP onto a starch–polyvinyl alcohol (PVA) matrix enabled both the rapid and visual onsite detection of ammonia and the determination of the RGB contents using a digital application. The blue content of the film linearly changed with the extent of the spoilage of fish and meat samples. This linear change enabled the film-based sensor to act as an excellent food quality indicator for hourly food quality monitoring. The aerial reversibility of the film empowered its use for many cycles without the use of any reagents.

Wasabi is a type of sauce made from the plant horseradish. During its production and storage, gas production sometimes occurs, which leads to changes in the flavor quality of wasabi. In this study, an electronic nose, electronic tongue, headspace-gas chromatography-mass spectrometry and headspace-gas chromatography-ion mobility spectrometry combined with multivariate statistical analysis were used to compare the differences in odor, taste and volatile components between normal and gas-producing wasabi. The results showed that normal and gas-producing wasabi samples could be distinguished by the electronic nose and electronic tongue. Furthermore, 72 and 65 volatile components were identified from wasabi by headspace-gas chromatography-mass spectrometry and headspace-gas chromatography-ion mobility spectrometry analysis, respectively. In addition, 33 key volatile components that caused the difference between normal and gas-producing wasabi were identified through variable projection importance index analysis. Therefore, normal and gas-producing wasabi could be effectively distinguished and their differences in odor, taste and volatile components could be clarified by the four flavor analysis techniques combined with multivariate statistical analysis, which provide a scientific basis for the quality control and process optimization of wasabi.

Rapid and accurate methods for tracing and identifying the origin of lamb are crucial for ensuring food authenticity and quality. This study developed a precise traceability method to determine the origin of lamb by integrating rapid evaporative ionization mass spectrometry (REIMS) with multivariate statistical analysis. Lamb samples from Xilin Gol, Ordos, and Hulun Buir ranches were identified by REIMS fingerprinting within 1 min. The discrimination model based on lipid molecular features achieved the highest recognition accuracy of 99.14% compared to models based on small-molecule metabolites (91.59%), fatty acids (98.52%), and full-spectrum molecules (98.49%). Furthermore, differential analyses were conducted to assess lamb meat from different origins and feeding methods (grazing versus feedlot) using REIMS fingerprints. Lamb products from the Xilin Gol ranch exhibited significantly lower glycerophosphate (PA) content compared to lambs from other regions, while grazing resulted in significantly lower PA content in lamb meat compared to those fed in feedlots. Additionally, meat from grazed lambs had significantly higher unsaturated fatty acid content, providing molecular evidence for its superior nutritional quality and distinct flavor profile compared to the lambs from feedlot systems. REIMS is a promising tool for rapid discrimination of lamb meat from different origins and feeding systems with high accuracy, offering valuable technical support for lamb origin traceability and quality assessment.

This study reports a novel ratiometric fluorescence sensor based on a tetraphenylethylene-bipyridine covalent organic framework (TPE-Bpy-COF) for the sensitive detection of Cu²⁺, leveraging the unique coordination properties of the bipyridine moieties. The interaction between Cu²⁺ and the nitrogen atoms in the bipyridine units induces fluorescence quenching at 500 nm through an efficient host–guest electron transfer mechanism, where excited-state electrons from the COF framework are transferred to the vacant orbitals of Cu²⁺. Upon excitation at 410 nm, the sensor exhibits a primary emission peak at 500 nm, which is quenched in the presence of Cu²⁺, while an overtone peak at 820 nm remains stable, serving as an internal reference for ratiometric measurements and significantly enhancing the accuracy and reliability of the sensor. The detection limit for Cu²⁺ is 0.1 μM, with the dual-emission system and the strong affinity of the bipyridine units for Cu²⁺, further improving the sensor's sensitivity and selectivity. Additionally, the sensor demonstrated excellent recovery rates in real water samples, confirming its practical applicability in environmental monitoring.

Bu Shen Jian Gu Oral Liquid (BSJG) is a hospital formulation commonly utilized in the treatment of fractures, joint dislocations, and rheumatoid arthritis. However, there has been no effective and straightforward method to comprehensively assess the quality of BSJG. In this experiment, a fingerprint of various batches of BSJG was established using high-performance liquid chromatography (HPLC). The results indicated that the 13 batches of oral liquid exhibited similarities. A total of 18 consensus peaks were found, and 8 components were identified: protocatechuic acid, chlorogenic acid, 2,3,5,4-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), isochlorogenic acid B, isochlorogenic acid A, naringin, isochlorogenic acid C, and emodin. Hierarchical cluster analysis (HCA), principal component analysis (PCA), and orthogonal partial least squares discrimination (OPLS-DA) were performed on 13 batches of BSJG, which showed differences among different batches. It is worth noting that peak 9 (TSG), peak 1, and peak 13 (naringin) may be the key components affecting the quality of this formulation. The content determination results showed that the eight components exhibit an excellent linear relationship within a specific range, with r > 0.9990. The content of 13 batches of oral liquid is different, and the component with a significant change in content is TSG, which may be related to the transportation and storage of medicinal materials. The fingerprinting method combined with multi-component content determination established in this study can serve as a reference for the quality standards of BSJG.

A method involving gas chromatography coupled with quadrupole/orbitrap high-resolution mass spectrometry (GC-Q/Orbitrap HRMS) with the QuEChERS method was developed to analyze 36 non-phthalate plasticizers in milk powder products. The samples were dissolved in 20% NaCl, extracted with acetonitrile, and purified using silica, PSA, and C₁₈. The results showed the excellent linear relationship of the calibration curves of 36 non-phthalate plasticizers in the range of 10–1000 ng mL⁻¹, with correlation coefficients (r) not less than 0.995. The limit of detection (LODs) of 36 non-phthalate plasticizers ranged from 0.02 to 0.04 mg kg⁻¹, and the limit of quantification (LOQs) ranged from 0.04 to 0.08 mg kg⁻¹. The recovery rates were between 64.1% and 116.5%, with the relative standard deviation less than 10%. The proposed method was applied to the detection and analysis of 36 non-phthalate plasticizers in 50 milk powder samples. The findings indicate that this highly sensitive, accurate, and high-throughput method is suitable for the rapid screening and identification of 36 non-phthalate plasticizers in milk powder products.

The study aims to evaluate and compare two advanced proteomic techniques, nanoLC-MALDI-MS/MS and nanoLC-TIMS-MS/MS, in characterizing extracellular vesicles (EVs) from the bronchoalveolar lavage fluid (BALF) of patients with asthma and idiopathic pulmonary fibrosis (IPF). Pulmonary diseases, driven by pollutants and infections, often necessitate detailed analysis of BALF to identify diagnostic biomarkers and therapeutic targets. EVs, which include exosomes, microvesicles, and apoptotic bodies, are isolated using filtration and ultracentrifugation, and their morphology, concentration, and size distribution are assessed through transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The proteomic profiles of these EVs are then analyzed using the aforementioned techniques, highlighting their unique and common proteins. The study found that nanoLC-TIMS-MS/MS identified significantly more proteins compared to nanoLC-MALDI-MS/MS. Functional analysis via Gene Ontology revealed pathways related to inflammation and cell signaling, underscoring the role of EVs in disease pathophysiology. The findings suggest that EVs in BALF can serve as valuable biomarkers and therapeutic targets in respiratory diseases, providing a foundation for future research and clinical applications.

Dextran 40, a typical high molecular weight carbohydrate drug refined through fermentation, is widely used in the clinical field in an injectable form. The final product obtained through fermentation may contain by-products such as fructose and residual sucrose, which carry a risk of adverse reactions. Current quality standards do not effectively control for the possible presence of carbohydrate residues, and methods for detecting such residues are lacking. This gap in quality control exists in the vast majority of existing carbohydrate drugs. This study established and compared liquid chromatography methods equipped with three different detectors (RID, MS, and CAD), selecting a convenient, rapid, and efficient HILIC-CAD method. This method combines the high sensitivity of the HILIC-MS method with the high throughput of the HILIC-RID method, using porous silica as the stationary phase and a high-precision charged aerosol detector in tandem, achieving rapid separation and quantification of fructose and sucrose. Additionally, pretreatment optimization was conducted to eliminate the impact of dextran 40 on the detection of fructose and sucrose. The method was validated, showing good repeatability, recovery, robustness, and linearity, capable of quantifying carbohydrate residues at approximately 3.3 ppm. This study compared the residual levels of fructose and sucrose in dextran 40 obtained from different purification processes, analyzing key purification operations that influence the extent of carbohydrate residues. These findings provide a reference for optimizing the production process of dextran 40, ensuring the quality of the drug and public drug safety. Furthermore, the approach used in this study for detecting carbohydrate residues is applicable to the quality control of other carbohydrate drugs produced via fermentation.