化学最新文献

Alkaline phosphatase (ALP) is abnormally expressed in some cancers and promotes the growth, metastasis, and invasion of cancer cells. The detection of ALP is of great significance for both pathological study and clinical detection. In this work, a europium (Eu)-based fluorescence detection sensor was prepared in a mild reaction condition. LaF₃:Eu nanoparticles was mixed with ethylene imine polymer (PEI) and Ag⁺ ions. PEI was used as stabilizer and reducing agent, and Ag⁺ ions were reduced as molecular-like silver clusters (ML-Ag NCs). The fluorescence of LaF₃:Eu nanoparticles was enhanced by ML-Ag NCs through energy transfer. When ascorbic acid 2-phosphate (AAP) was hydrolyzed to ascorbic acid (AA) in the presence of ALP, AA reduced Ag⁺ ions to silver nanoparticles (Ag NPs) and quenched the fluorescence of LaF₃:Eu/PEI/Ag. The activity of ALP was detected by measuring the fluorescence intensity of Eu³⁺ at 618 nm. In the concentration range from 2.0 to 16.0 U/L, the fluorescence intensity ratio ((F₀-F)/F₀) had a linear relationship with the logarithm of ALP concentration. The limit of detection (LOD) was 1.3 U/L. Moreover, the ALP activity was detected successfully in cancer cells by this method. The sensing platform has application potential in the detection of ALP activity in biological systems.

The ideal photoelectrode and efficient signaling strategy are pivotal to achieve sensitive photoelectrochemical (PEC) analysis. Here, a multipath collaborative signal amplification-based PEC immunosensor was constructed for the ultrasensitive detection of cytokeratin 19 fragment 21-1. Specifically, the photoelectrode fabricated by Z-scheme In₂O₃/g-C₃N₄ heterojunction showed enhanced photocurrent intensity in response to visible light. Meanwhile, the signal probe, horseradish peroxidase functionalized dopamine-melanin nanosphere@Au nanoparticles (HRP-Dpa-melanin NS@AuNPs), were introduced into the system. When the target exists, the signal probe can induce multiple quenching of the photocurrent due to the competition of light absorption, steric hindrance and HRP-mediated biocatalytic precipitation, which effectively inhibit light, electron donor, and electron access to the photoelectrode. The fabricated immunosensor exhibits a wide linear range from 1.0 × 10^-3 - 1.0 × 10² ng mL^-1 with the detection limit of 0.35 pg mL^-1 (S/N = 3) for cytokeratin 19 fragment 21-1 detection. The study enhances sensitivity for PEC detection by utilizing the superior Z-scheme heterojunction photoelectrode, providing a valuable method that combines multiple signal pathways for a synergistic effect in bioanalysis.

A large number of Chinese herbal medicines (CHMs) are included in daily recipes, but their pesticide residues have aroused more and more concerns. In this paper, an electrochemiluminescence aptasensor was constructed for the trace detection of acetamiprid (ACE) in Angelica sinensis and Lycium barbarum. Possessing a large specific surface area, UiO-66 was modified with amino groups to improve biocompatibility, and the addition of AuNPs allowed UiO-66-NH₂ to catalyze the formation of excited states of luminescent molecules (TPrA^⁎; Ru(bpy)₃^2+⁎), and AuNPs@UiO-66-NH₂ was used to bridge the aptamer (Au-S) and luminescent substrate (peptide bond). The conventional luminescent reagent Ru(bpy)₃²⁺ was doped with multi-walled carbon nanotubes (MWCNTs) to obtain a more powerful and stable light signal. After optimizing the experimental parameters, the aptasensor could give results in 10 min with a detection range from 1×10^-2-1×10⁴ nM and a lower limit of detection (LOD) of 0.8 pM. The LOD of the study was at least one order of magnitude lower than that of the fluorescence detection method. Furthermore, the accuracy of the aptasensor was validated for spiked recovery experiments.

Miniature mass spectrometers exhibit immense application potential in on-site detection due to their small size and low cost. However, their detection accuracy is severely affected by factors such as sample pre-processing and environmental conditions. In this study, we propose a data processing method based on long short-term memory-ensemble empirical mode decomposition (LSTM-EEMD) to improve the quality of on-site detection data from miniature mass spectrometers. The EEMD method can clearly decompose the different physical feature components in the small-scale spectrometer signals, while the LSTM method can adaptively learn the internal feature relationships of the signals. Thus, by combining the two, the parameters for the EEMD signal reconstruction can be optimized in an adaptive manner, obtaining the optimized coefficients. Compared to the previous EEMD feature enhancement approach, the LSTM-EEMD method not only significantly improves the coefficient of determination (R²) and relative standard deviation (RSD) of the data, enhancing the linear range, but also achieves fully adaptive processing throughout the workflow, greatly boosting the efficiency. By leveraging a miniature mass spectrometer, data for N-acetyl-l-aspartic acid (NAA), 2-Hydroxyglutarate (2-HG), and γ-Aminobutyric acid (GABA) in actual blood samples have been obtained. The experimental results demonstrate that the LSTM-EEMD method can markedly enhance the accuracy and usability of the biological sample data in practical testing, providing new perspectives and possibilities for research and applications in the relevant domain.

A novel, portable, disposable, affordable, and environmentally friendly paper-based analytical device (PAD) was designed for on-site determination of carmine and carminic acid. This platform utilized paper test strips with a chitosan coating as an adsorption layer, which was characterized using scanning electron microscope, energy-dispersive X-ray analysis, and water contact angle measurement. Carmine and carminic acid could be efficiently adsorbed on chitosan-coated paper test strips, producing distinct colors that could be captured using a smartphone camera without the need for an elution step. Notably, by utilizing the Hue component of the HSL model, it was possible to differentiate between carmine and carminic acid, confirming their presence in a sample. Furthermore, the color saturation intensity changed in a concentration-dependent manner, allowing for the determination of carmine and carminic acid concentrations in the ranges of 200-800 μg/mL and 20-100 μg/mL, respectively. Additionally, the created test strip could be used to measure the percentage of carminic acid in the presence of carmine. The developed PAD enabled the quantification of carmine in various food samples without the need for reagents or complex equipment. The environmental impact of this method was found to be positive based on assessments using GAPI and AGREE tools.

Genotoxicants originating from inflammation, diet, and environment can covalently modify DNA, possibly initiating the process of carcinogenesis. DNA adducts have been known for long, but the old methods allowed to target only a few known DNA adducts at a time, not providing a global picture of the "DNA adductome". DNA adductomics is a new research field, aiming to screen for unknown DNA adducts by high resolution mass spectrometry (HRMS). However, DNA adductomics presents several analytical challenges such as the need for high sensitivity and for the development of effective screening approaches to identify novel DNA adducts. In this work, a sensitive untargeted DNA adductomics method was developed by using ultra-high performance liquid chromatography (UHPLC) coupled via an ESI source to a quadrupole-time of flight mass spectrometric instrumentation. Mobile phases with ammonium bicarbonate gave the best signal enhancement. The MS capillary voltage, cone voltage, and detector voltage had most effect on the response of the DNA adducts. A low adsorption vial was selected for reducing analyte loss. Hybrid surface-coated analytical columns were tested for reducing adsorption of the DNA adducts. The optimized method was applied to analyse DNA adducts in calf thymus, cat colon, and human colon DNA by performing a MS^E acquisition (all-ion fragmentation acquisition) and screening for the loss of deoxyribose and the nucleobase fragment ions. Fifty-four DNA adducts were tentatively identified, hereof 38 never reported before. This is the first untargeted DNA adductomics study on human colon tissue, and one of the few untargeted DNA adductomics studies in the literature reporting the identification of such a high number of unknowns. This demonstrates promising results for the application of this sensitive method in future human studies for investigating novel potential cancer-causing factors.

The capability to detect a small number of miRNAs in clinical samples with simplicity, selectivity, and sensitivity is immensely valuable, yet it remains a daunting task. Here, we described a novel Mango II aptamers-based sensor for the one-pot, sensitive and specific detection of miRNAs. Target miRNA-initiated mediated catalyzed hairpin assembly (CHA) would allow for the production of plenty of DNA duplexes and the formation of the complete T7 promoter, motivating the rolling circle transcription (RCT). Then, the subsequent RCT process efficiently generates a huge number of repeating RNA Mango II aptamers, brightened by the incorporation of fluorescent dye TO1-B for miRNA quantification, realizing label-free and high signal-to-background ratio. Moreover, this assay possesses a remarkable ability to confer high selectivity, enabling the distinction of miRNAs among family members with mere 1- or 2- nucleotide (nt) differences. By employing the proposed assay, we have successfully achieved a sensitive evaluation of miR-21 content in diverse cell lines and clinical serum samples. This offers a versatile approach for the sensitive assay of miRNA biomarkers in molecular diagnosis.

4-n-butylresorcinol (4nBR) is a frequently utilized as whitening ingredients in skincare cosmetics. Compared with other whitening ingredients, it can effectively inhibit tyrosinase with lower toxicity and superior inhibition efficacy. Under alkaline conditions, an induced oxidative coupling reaction can occur between 4nBR and dopamine (DA) to generate strong fluorescent substance azamonardine with an intense emission band centering at 476 nm when excited at 440 nm. This phenomenon can be used to establish a fluorescence analysis method for 4nBR. The results indicated that the linear range of the method was 1.0-24.0 nmol L^-1, and the detection limit was as low as 0.25 nmol L^-1. The method showed high sensitivity, good selectivity, mild experimental conditions and low cost. The proposed method was successfully used to detect 4nBR in cosmetics, and the results were consistent with those of HPLC. The spiking recoveries were between 98.2% and 108 %.

Background: Palliative care aims to improve or maintain quality of life for patients with life-limiting or life-threatening diseases. Limited research shows that palliative care is associated with reduced intensive care unit length of stay and use of high-cost resources.

Methods: This was an observational, non-experimental comparison group study on all patients 18 years or older admitted to any intensive care unit (ICU) at Memorial Hermann - Texas Medical Center for 7 to 30 days from August 2013 to December 2015. Length of stay (LOS) and hospital costs were compared between the treatment group of patients with palliative care in the ICU and the control group of patients with usual care in the ICU. To adjust for confounding of the palliative care consultation on LOS and hospital cost, an inverse probability of treatment weighted method was conducted. Generalized linear models using gamma distribution and log link were estimated. All costs were converted to 2015 US dollars.

Results: Mean LOS was 13 days and mean total hospital costs were USD 58,378. In adjusted and weighted analysis, LOS for the treatment group was 8% longer compared to the control group. The mean total hospital cost was estimated to decrease by 21% for the treatment group versus the control group. We found a reduction of USD 33,783 in hospital costs per patient who died in the hospital and reduction of USD 9113 per patient discharged alive.

Conclusion: Palliative care consultation was associated with a reduction in the total cost of hospital care for patients with life-limiting or life-threatening diseases.

Objective: The principal aim of this study was to identify, systematically and transparently, clinical practice guidelines (CPGs) on palliative sedation from around the world. Methods: A systematic search was performed using 5 databases, grey literature search tools, citation tracking, and contact with palliative care experts across the world. Current CPGs accredited by an international, national, or regional authority, published in English, German, French, or Italian, were subjected to content analysis. Results: In total, 35 CPGs from 14 countries and 1 international CPG were included in the analysis. The CPGs had diverse formal characteristics. Their thematic scope was difficult to analyze and compare because of differences in the terms and definitions of palliative sedation in those texts. We identified 3 main situations: (1) CPGs with a fully explicit thematic scope; (2) CPGs with a partially explicit thematic scope; and (3) CPGs without an explicit thematic scope. Several CPGs explicitly stated what forms of sedation were excluded from the text. However, this presentation was often confusing. Conclusion: Our review provides several pieces of information that could guide international reflections in this field, and be used to develop or update CPGs at all levels. Efforts should be made to clarify the thematic scope of each CPG on palliative sedation, in order to generate an understanding of the forms of this therapy addressed in the text.