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This trend article reviews papers with hyphenated high-resolution mass spectrometry (HRMS) approaches applied in analytical toxicology, particularly in clinical and forensic toxicology published since 2016 and referenced in PubMed. The article focuses on the question of whether HRMS has or will become the all-in-one device in these fields as supposed by the increasing number of HRMS presentations at scientific meetings, corresponding original papers, and review articles. Typical examples for the different application fields are discussed such as targeted or untargeted drug screening, quantification, drug metabolism studies, and metabolomics approaches. Considering the reviewed papers, HRMS is currently the only technique that fulfills the criteria of an all-in-one device for the various applications needed in analytical toxicology. Graphical abstract [ABSTRACT FROM AUTHOR]

Dynamic spectroscopy (DS) theoretically eliminates individual differences and the impact of measurement conditions on accuracy and can achieve high-precision noninvasive blood component analysis. To further improve the extraction quality of DS, this paper proposes a photoplethysmography (PPG) signal waveform proportion extraction method, which realizes the extraction of DS by calculating the proportion coefficient between PPG waveforms. To verify the effectiveness of our method, the transmission spectra of 146 volunteers' fingers and the true value of platelet content (wavelength 600–1100 nm, platelet content range 32 × 109/L–512 × 109/L) were collected. Then the DS was extracted by the single-trail method and this method, and the prediction model is established by PLS. The experimental data showed, compared with the single-trail method, that the modeling effect of the PPG waveform proportion method is significantly improved, the Rc increased 9.61%, the RMSEc decreased 31.56%, the MAPc decreased from 12 to 6%, and the Rp increased 42.92%, the RMSEP reduced 24.39%, and MAPp decreased from 13 to 11%. The results show that the PPG waveform proportion method proposed in this paper has a higher model correlation coefficient and lower prediction error, significantly improves the extraction quality of DS, further improves the accuracy of noninvasive blood component quantitative analysis, and helps to promote the application process of noninvasive detection of blood components. [ABSTRACT FROM AUTHOR]

A simple wipe sampling procedure was developed for the surface contamination determination of ten cytotoxic drugs: cytarabine, gemcitabine, methotrexate, etoposide phosphate, cyclophosphamide, ifosfamide, irinotecan, doxorubicin, epirubicin and vincristine. Wiping was performed using Whatman filter paper on different surfaces such as stainless steel, polypropylene, polystyrol, glass, latex gloves, computer mouse and coated paperboard. Wiping and desorption procedures were investigated: The same solution containing 20% acetonitrile and 0.1% formic acid in water gave the best results. After ultrasonic desorption and then centrifugation, samples were analysed by a validated liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in selected reaction monitoring mode. The whole analytical strategy from wipe sampling to LC-MS/MS analysis was evaluated to determine quantitative performance. The lowest limit of quantification of 10 ng per wiping sample (i.e. 0.1 ng cm) was determined for the ten investigated cytotoxic drugs. Relative standard deviation for intermediate precision was always inferior to 20%. As recovery was dependent on the tested surface for each drug, a correction factor was determined and applied for real samples. The method was then successfully applied at the cytotoxic production unit of the Geneva University Hospitals pharmacy. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The emerging field of RNA nanotechnology harnesses the versatility of RNA molecules to generate nature-inspired systems with programmable structure and functionality. Such methodology has therefore gained appeal in the fields of biosensing and diagnostics, where specific molecular recognition and advanced input/output processing are demanded. The use of RNA modules and components allows for achieving diversity in structure and function, for processing information with molecular precision, and for programming dynamic operations on the grounds of predictable non-covalent interactions. When RNA nanotechnology meets bioanalytical chemistry, sensing of target molecules can be performed by harnessing programmable interactions of RNA modules, advanced field-ready biosensors can be manufactured by interfacing RNA-based devices with supporting portable platforms, and RNA sensors can be engineered to be genetically encoded allowing for real-time imaging of biomolecules in living cells. In this article, we report recent advances in RNA-based sensing technologies and discuss current trends in RNA nanotechnology-enabled biomedical diagnostics. In particular, we describe programmable sensors that leverage modular designs comprising dynamic aptamer-based units, synthetic RNA nanodevices able to perform target-responsive regulation of gene expression, and paper-based sensors incorporating artificial RNA networks. [ABSTRACT FROM AUTHOR]

A novel fluorescent sensor based on bovine serum albumin stabilized gold/silver nanoclusters (BSA-Au/Ag NCs) was developed for sensitive and facile detection of alkaline phosphatase (ALP) activity. For this fluorescent sensor, ascorbic acid 2-phosphate (AAP) was decomposed into ascorbic acid (AA) and phosphate by catalysis with ALP. The initial red fluorescence of the BSA-Au/Ag NCs was effectively quenched by KMnO4 and then the fluorescence was recovered by addition of AA. The mechanism of interaction between BSA-Au/Ag NCs and KMnO4 and AA was studied with use of the fluorescence lifetime and UV-vis absorption spectra. The results indicated that the oxidation/reduction modulated by KMnO4/AA led to surface structure destruction/restoration of the BSA-Au/Ag NCs, resulting in fluorescence quenching/recovery. The proposed fluorescence-based method based on a dark background was used to detect ALP and had excellent sensitivity, with a detection limit of 0.00076 U/L. Moreover, the method was applied to the determination of added analytes, with satisfactory recoveries (97.0-105.0 %). In a simulated eutrophic water body, this method successfully detected ALP in actual water samples and could monitor the dynamic changes of ALP activity through visual observation. More importantly, the proposed fluorescent sensor not only has the advantages of simple operation and high sensitivity but has also been successfully used on filter paper to establish a rapid and visual test paper for ALP. [ABSTRACT FROM AUTHOR]

Explores the progress and emerging trends in the kinetic aspects of analytical chemistry. Kinetics techniques for analytical chemistry; Millisecond kinetics on microchips; Characteristics of an ideal biosensor; Outlook for kinetic approaches.

A phosphorimetric method for the determination of o-phenylphenol (OPP) using filter paper as solid support and Tl(I) as heavy metal enhancer of the phosphorescent signal is proposed. The phosphorescence measurements were carried out by placing the paper with the sample between two plates of quartz, thus avoiding the quenching effect produced by atmospheric oxygen and moisture. The linear dynamic range of the method was 0.5–4.0 mg L-1 and the detection and quantification limits were 0.03 and 0.11 mg L-1, respectively. The precision of the method (expressed as relative standard deviation) was 1.7% for a sample containing 2.0 mg L-1 of analyte. The method has been applied to the determination of OPP in different types of water, lettuce, string beans and peppers, with recoveries ranging between 97.1 and 100.7% [ABSTRACT FROM AUTHOR]

Intense label-free surface-enhanced Raman scattering (SERS) spectra of serum samples were rapidly obtained on Ag plasmonic paper substrates upon 785 nm excitation. Spectra from the hepatocellular carcinoma (HCC) patients showed consistent differences with respect to those of the control group. In particular, uric acid was found to be relatively more abundant in patients, while hypoxanthine, ergothioneine, and glutathione were found as relatively more abundant in the control group. A repeated double cross-validation (RDCV) strategy was applied to optimize and validate principal component analysis-linear discriminant analysis (PCA-LDA) models. An analysis of the RDCV results indicated that a PCA-LDA model using up to the first four principal components has a good classification performance (average accuracy was 81%). The analysis also allowed confidence intervals to be calculated for the figures of merit, and the principal components used by the LDA to be interpreted in terms of metabolites, confirming that bands of uric acid, hypoxanthine, ergothioneine, and glutathione were indeed used by the PCA-LDA algorithm to classify the spectra. [ABSTRACT FROM AUTHOR]

Microbial resistance to currently available antibiotics poses a great threat in the global fight against infections. An important step in determining bacterial antibiotic resistance can be selective DNA sequence capture and fluorescence labeling. In this paper, we demonstrate the fabrication of simple, robust, inexpensive microfluidic devices for DNA capture and fluorescence detection of a model antibiotic resistance gene sequence. We laser micromachined polymethyl methacrylate microchannels and enclosed them using pressure-sensitive adhesive tapes. We then formed porous polymer monoliths with DNA capture probes in these microchannels and used them for sequence-specific capture, fluorescent labeling, and laser-induced fluorescence detection of picomolar (pM) concentrations of synthetic and plasmid antibiotic resistance gene targets. The relative fluorescence for the elution peaks increased with loaded target DNA concentration. We observed higher fluorescence signal and percent recovery for synthetic target DNA compared to plasmid DNA at the same loaded target concentration. A non-target gene was used for control experiments and produced < 3% capture relative to the same concentration of target. The full analysis process including device fabrication was completed in less than 90 min with a limit of detection of 30 pM. The simplicity of device fabrication and good DNA capture selectivity demonstrated herein have potential for application with processes for bacterial plasmid DNA extraction and single-particle counting to facilitate determination of antibiotic susceptibility. [ABSTRACT FROM AUTHOR]

The research interest in wearable sensors has tremendously increased in recent years. Amid the different biosensors, electrochemical biosensors are unparalleled and ideal for the design and manufacture of such flexible and wearable sensors because of their various benefits, including convenient operation, quick response, portability, and inherent miniaturization. A number of studies on flexible and wearable electrochemical biosensors have been reported in recent years for invasive/non-invasive and real-time monitoring of biologically relevant molecules such as glucose, lactate, dopamine, cortisol, and antigens. To attain this, novel two-dimensional nanomaterials and their hybrids, various substrates, and detection methods have been explored to fabricate flexible conductive platforms that can be used to develop flexible electrochemical biosensors. In particular, there are many advantages associated with the advent of two-dimensional materials, such as light weight, high stretchability, high performance, and excellent biocompatibility, which offer new opportunities to improve the performance of wearable electrochemical sensors. Therefore, it is urgently required to study wearable/flexible electrochemical biosensors based on two-dimensional nanomaterials for health care monitoring and clinical analysis. In this review, we described recently reported flexible electrochemical biosensors based on two-dimensional nanomaterials. We classified them into specific groups, including enzymatic/non-enzymatic biosensors and affinity biosensors (immunosensors), recent developments in flexible electrochemical immunosensors based on polymer and plastic substrates to monitor biologically relevant molecules. This review will discuss perspectives on flexible electrochemical biosensors based on two-dimensional materials for the clinical analysis and wearable biosensing devices, as well as the limitations and prospects of the these electrochemical flexible/wearable biosensors. Graphical abstract [ABSTRACT FROM AUTHOR]

Wavelength interrogation surface plasmon resonance imaging (WSPRi) sensing has unique advantages in high-throughput imaging detection. The refractive index resolution (RIR) of WSPRi is limited to the order of 10−6 RIU. This paper demonstrates a novel WSPRi sensing system with a wavelength scanning device of an acousto-optic tunable filter (AOTF) and a low-cost speckle-free SPR excitation source of a halogen lamp. We developed a sensitive quasi-phase extraction method for data processing. The new technique achieved an RIR of 8.84×10−7 RIU, which is the first WSPRi system that has an RIR in the order of 10−7 RIU. Moreover, we performed a real-time recording of the formation of the coffee ring effect during brine evaporation and enhanced the biosensor performance of SPR for the first time. We believe the higher RIR and accuracy of the system will benefit more potential applications toward exploring the biomolecules' behaviors in biological and biochemistry studies. [ABSTRACT FROM AUTHOR]

We developed and evaluated two-level, namely 2017011 and 2017012, serum-based reference materials (RMs) for 17 beta-estradiol (17 β-E2) by the reference method of isotope dilution liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) from the remaining serum samples after routine clinical tests, to help improve clinical routine testing and provide the traceability of results. This paper describes the development process of these RMs. The National Metrology Institute of Japan (NMIJ) certified reference material (CRM) 6004-a was used as the primary RM for the measurement of 17 β-E2. These serum-based RMs showed satisfactory homogeneity and stability. They also assessed the commutability between the reference method and the three routine clinical immunoassay systems. Besides, a collaborative study was carried out in five reference laboratories, all of which had been accredited by the China National Accreditation Service for Conformity Assessment (CNAS) in accordance with ISO/WD 15725-1. Statistical analysis of raw results and uncertainty assessment obtained certified values: 2017011 was 445.2 ± 39.0 pmol/L, and 2017012 was 761.9 ± 35.5 pmol/L. [ABSTRACT FROM AUTHOR]

Manufacturers of nanoparticle-based products rely on detailed information about critical process parameters, such as particle size and size distributions, concentration, and material composition, which directly reflect the quality of the final product. These process parameters are often obtained using offline characterization techniques that cannot provide the temporal resolution to detect dynamic changes in particle ensembles during a production process. To overcome this deficiency, we have recently introduced Optofluidic Force Induction (of2i) for optical real-time counting with single particle sensitivity and high throughput. In this paper, we apply of2i to highly polydisperse and multi modal particle systems, where we also monitor evolutionary processes over large time scales. For oil-in-water emulsions we detect in real time the transition between high-pressure homogenization states. For silicon carbide nanoparticles, we exploit the dynamic of2i measurement capabilities to introduce a novel process feedback parameter based on the dissociation of particle agglomerates. Our results demonstrate that of2i provides a versatile workbench for process feedback in a wide range of applications. [ABSTRACT FROM AUTHOR]

Mineral oil hydrocarbons (MOH) contain a wide structural diversity of molecules, for which the reference method of analysis is the online coupled liquid chromatography-gas chromatography with flame ionization detection (LC-GC-FID). These compounds are very heterogeneous from a toxicological viewpoint, and an accurate risk assessment when dealing with a MOH contamination can only be performed if sufficient information is available on the types of structures present (i.e., number of carbons, degree of alkylation, number of aromatic rings). Unfortunately, the separation performances of the current LC-GC-FID method are insufficient for such characterization, not even mentioning the possible coelution of interfering compounds which additionally hinder MOH determination. Comprehensive two-dimensional gas chromatography (GC × GC), while mostly used for confirmation purposes in the past, starts to prove its relevance for overcoming the weaknesses of the LC-GC method and reaching even better the analytical requirements defined in the latest EFSA opinion. The present paper therefore aims at highlighting how GC × GC has contributed to the understanding of the MOH topic, how it has developed to meet the requirements of MOH determination, and how it could play a role in the field for overcoming many of the current analytical and toxicological challenges related to the topic. [ABSTRACT FROM AUTHOR]

Early, express, and reliable detection of cancer can provide a favorable prognosis and decrease mortality. Tumor biomarkers have been proven to be closely related to tumor occurrence and development. Conventional tumor biomarker detection based on genomic, proteomic, and metabolomic methods is time and equipment-consuming and always needs a specific target marker. Surface-enhanced Raman scattering (SERS), as a non-invasive ultrasensitive and label-free vibrational spectroscopy technique, can detect cancer-related biomedical changes in biofluids. In this paper, 110 serum samples were collected from 30 healthy controls and 80 cancer patients (including 30 bladder cancer (BC), 30 adrenal cancer (AC), and 20 acute myeloid leukemia (AML)). One microliter of blood serum was mixed with 1 μl silver colloid and then was air-dried for SERS measurements. After spectral data augmentation, one-dimensional convolutional neural network (1D-CNN) was proposed for precise and rapid identification of healthy and three different cancers with high accuracy of 98.27%. After gradient-weighted class activation mapping (Grad-CAM) based spectral interpretation, the contributions of SERS peaks corresponding to biochemical substances indicated the most potential biomarkers, i.e., L-tyrosine in bladder cancer; acetoacetate and riboflavin in adrenal cancer and phospholipids, amide-I, and α-Helix in acute myeloid leukemia, which might provide an insight into the mechanism of intelligent diagnosis of different cancers based on label-free serum SERS. The integration of label-free SERS and deep learning has great potential for the rapid, reliable, and non-invasive detection of cancers, which may significantly improve the precise diagnosis in clinical practice. [ABSTRACT FROM AUTHOR]

This document is a summary of an editorial titled "Emerging Trends in Electrochemical Analysis" published in the journal Analytical & Bioanalytical Chemistry. The editorial discusses three key emerging trends in the field of electrochemical analysis. The first trend is the transition from traditional research on bulk electrodes to studying single particles or molecules. This is made possible by the development of functional materials such as metal-organic framework compounds and polymer conductors. The second trend involves the use of in-situ spectroscopic and optical techniques with high spatiotemporal resolution to decode the properties of electrochemical systems. These techniques allow for the capture of transient intermediate states and kinetic processes of electrochemical reactions. The third trend is the integration of digital and computational methods, including artificial intelligence, into electrochemical analysis. These methods enhance the handling and analysis of information-rich data and enable the design and optimization of electrodes and electrochemical cells using three-dimensional printing. The editorial also highlights a topical collection of articles that cover various aspects of electrochemical analysis, including research papers, critical reviews, and papers in the forefront. The authors express their appreciation to the contributors and reviewers for their work in organizing the collection. The summary concludes with brief biographies of the two authors, Wei Wang and Adam T. Woolley, who are experts in the field of electrochemical analysis. [Extracted from the article]

Presents updates on issues and events concerning the journal "Analytical and Bioanalytical Chemistry" as of December 17, 2004. Contributions of the late professor Wilhelm Fresenius to the journal; Purpose of the ABC Best Paper Award to be given by the journal editors; Features of the Analytical Challenge section of the journal; Goal of the changes in the cover of the journal.

The direct detection of dopamine (DA) in human body fluids is a great challenge for medical diagnostics of neurological disorders like Parkinson's disease, Alzheimer's disease, senile dementia, and schizophrenia. In this work, a simple and turn off luminescence sensing of DA based on bovine serum albumin (BSA)-capped manganese-doped zinc sulphide quantum dots (Mn:ZnS/BSA QDs) is developed. The Mn:ZnS/BSA QDs were synthesized by a chemical co-precipitation method. Due to the special interaction of DA with BSA and metal ions, Mn:ZnS/BSA QDs can serve as an effective sensing platform for DA. The luminescence of Mn:ZnS/BSA QDs decreased linearly with increasing concentration of DA in the range from 6.6 to 50.6 nM. The limit of detection is 2.02 nM. The driving force for the luminescence quenching is partly provided by ground-state complex formation of QDs with DA. The photo-induced electron transfer from the conduction band of QDs to oxidized dopamine (quinone) also favors quenching. The Mn:ZnS/BSA QDs are barely interfered with by other competing biomolecules except catecholamine neurotransmitter like epinephrine. Moreover, this method is used in the analysis of DA-spiked human serum and human urine samples and good recovery percentages are found. To assess the utility of the developed sensor, paper strip assay was also successfully conducted. [ABSTRACT FROM AUTHOR]

The application of contaminated paper sludge on arable land in southwest Germany caused the occurrence of a broad range of poly- and perfluoroalkyl substances (PFASs) on soil. Recently, the dead-end transformation products (TPs) perfluorooctanoic acid and perfluorooctanesulfonic acid were detected in groundwater and drinking water. The precursors and other transformation products mostly remained unknown. Therefore, HRMS screening by Kendrick mass analysis and assignment of homologous series in combination with suspect screening were applied to identify original PFASs and their TPs in four different soil samples from sites where contaminated paper sludge was applied. In total, twelve compound classes comprising more than 61 PFASs could be fully or tentatively identified. The data reveal that contamination mainly originates from polyfluorinated dialkylated phosphate esters (from 4:2/6:2 to 12:2/14:2), N-ethyl perfluorooctane sulfonamide ethanol–based phosphate diesters (only C8/C8) and transformation products of these precursors. Contamination patterns can be attributed to PFASs used for paper impregnation and can vary slightly from site to site. [ABSTRACT FROM AUTHOR]

Trinitrotoluene (TNT) is a widely used explosive belonging to the family of nitroaromatic compounds, and its misuse poses a significant threat to society. Herein, we propose a Tb-BSA-AuNC fluorescent and colorimetric sensing probe for the selective onsite detection of TNT in the aqueous phase. Tb-doped BSA-protected gold nanoclusters (Tb-BSA-AuNCs) were synthesized by a microwave-assisted method, and TNT detection was carried out utilizing the chemistry of Meisenheimer complex formation. Tb doping of gold nanoclusters was demonstrated to facilitate better electron shuttling effects and thereby improve the efficiency of complex formation between the TNT and gold nanoclusters. A paper strip assay was also developed for TNT detection with the designed probe. Limits of detection and quantification of 0.2136 mM and 0.7120 mM, respectively, were achieved. [ABSTRACT FROM AUTHOR]

Nanolayer and nanolayer by nanolayer deposition of nanofilms of Ag and C using cold plasma in sequences (Ag, Ag-C, Ag-Ag-C), on porous paper, were used to design three disposable stochastic sensors for the assay of amyloid polypeptide from whole blood. The nanofilms were modified with α-cyclodextrin. The test developed using the nanofilm-based disposable stochastic sensors is used for early detection of diabetes. The wider linear concentration range (1.00 × 10−6–1.00 ng mL−1) and the lower limit of quantification (1.00 × 10−6ng mL−1) were obtained using the disposable stochastic sensors based on Ag-C and Ag-Ag-C, while the highest sensitivity (3.19 × 104 s−1/μg mL−1) was recorded using the disposable stochastic sensor based on Ag-Ag-C. The screening methods were fully validated using whole blood samples from confirmed patients, when the recovery of the islet amyloid polypeptide was higher than 98.00%. [ABSTRACT FROM AUTHOR]

Bloodstains found at crime scenes contain immense information about the crime; thus, studies involving analysis of small molecules in bloodstains have been conducted. However, most of these studies have not accounted for the difference in the results of small molecule analysis due to the surface of bloodstains. To evaluate the "surface effect," we prepared bloodstains on seven surfaces, including both absorbent and non-absorbent surfaces, and performed global small molecule analysis by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). We used three indicators: (1) count recovery rate (%) of molecular features (MFs), (2) the number of MFs extracted from the surface without bloodstains, and (3) difference in abundance recovery rate (%) of MFs, to determine the ranking of the seven surfaces in the order of their similarity with blood. We also confirmed the correlation between each surface and blood through multivariate analysis. We found that the non-absorbent surfaces ranked better than the absorbent surfaces; wooden flooring was ranked as the most efficient surface, followed by stainless, vinyl flooring, glass, tile, filter paper, and mixed cotton. This study will help in the selection of the most efficient surface for collection of bloodstains for small molecule analysis from a crime scene. This is the first study to identify the effects of surface on extraction of global small molecules from bloodstains; it will help forensic scientists in obtaining more accurate information from small molecules present in the bloodstains collected at the field. [ABSTRACT FROM AUTHOR]

At present, in the chemical quantitative analysis of complex solutions based on spectroscopy, the accuracy of the content analysis of complex solution is difficult to meet the requirements due to the overlapping spectral lines, low signal-to-noise ratio, and scattering characteristics of various components of complex solution. In this paper, the logarithmic method is used to preprocess the spectral data in the spectral preprocessing stage, and the two-position and multi-mode joint spectral strategy of "M plus N" theory is applied to the quantitative analysis of serum components. The serum samples are illuminated by dual-position ultraviolet LED light source, and the two spectra of the vertical position and the coaxial facing position of the light source and the optical fiber are collected respectively. Then the partial least square (PLS) method was used to establish models to analyze the concentration of total bilirubin in serum by the spectrum of vertical position, the spectrum of coaxial facing position, and the spectrum of the combination of the former two. Among the experimental results, the model established by the combination of the two spectra collected by two positions has a good result. The correlation coefficient of all samples predicted by this model is 0.971223, and the root mean square error is 1.96645 μmol/L. This study shows that the method of the logarithmic, collecting spectra and analyzing the composition content of complex solutions by using the multi-location and multi-mode strategy of "M + N" theory can effectively improve the prediction accuracy of the model and has practical significance for the chemical quantitative analysis of complex solutions based on spectroscopy. [ABSTRACT FROM AUTHOR]

Biopharmaceuticals have revolutionized the field of medicine in the types of active ingredient molecules and treatable indications. Adoption of Quality by Design and Process Analytical Technology (PAT) frameworks has helped the biopharmaceutical field to realize consistent product quality, process intensification, and real-time control. As part of the PAT strategy, Raman spectroscopy offers many benefits and is used successfully in bioprocessing from single-cell analysis to cGMP process control. Since first introduced in 2011 for industrial bioprocessing applications, Raman has become a first-choice PAT for monitoring and controlling upstream bioprocesses because it facilitates advanced process control and enables consistent process quality. This paper will discuss new frontiers in extending these successes in upstream from scale-down to commercial manufacturing. New reports concerning the use of Raman spectroscopy in the basic science of single cells and downstream process monitoring illustrate industrial recognition of Raman's value throughout a biopharmaceutical product's lifecycle. Finally, we draw upon a nearly 90-year history in biological Raman spectroscopy to provide the basis for laboratory and in-line measurements of protein quality, including higher-order structure and composition modifications, to support formulation development. [ABSTRACT FROM AUTHOR]

Numerous approaches have been proposed to overcome the intrinsically low selectivity of surface-enhanced Raman spectroscopy (SERS), and the modification of SERS substrates with diverse recognition molecules is one of such approaches. In contrast to the use of antibodies, aptamers, and molecularly imprinted polymers, application of cyclodextrins (CDs) is still developing with less than 100 papers since 1993. Therefore, the main goal of this review is the critical analysis of all available papers on the use of CDs in SERS analysis, including physicochemical studies of CD complexation and the effect of CD presence on the Raman enhancement. The results of the review reveal that there is controversial information about CD efficiency and further experimental investigations have to be done in order to estimate the real potential of CDs in SERS-based analysis. [ABSTRACT FROM AUTHOR]

Nucleotide sugars (NS) fulfil important roles in all living organisms and in humans, related defects result in severe clinical syndromes. NS can be seen as the "activated" sugars used for biosynthesis of a wide range of glycoconjugates and serve as substrates themselves for the synthesis of other nucleotide sugars. NS analysis is complicated by the presence of multiple stereoisomers without diagnostic transition ions, therefore requiring separation by liquid chromatography. In this paper, we explored weak anion-exchange/reversed-phase chromatography on a hybrid column for the separation of 17 nucleotide sugars that can occur in humans. A robust and reproducible method was established with intra- and inter-day coefficients of variation below 10% and a linear range spanning three orders of magnitude. Application to patient fibroblasts with genetic defects in mannose-1-phosphate guanylyltransferase beta, CDP-l-ribitol pyrophosphorylase A, and UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase showed abnormal levels of guanosine-5′-diphosphate-α-d-mannose (GDP-Man), cytidine-5′-diphosphate-l-ribitol (CDP-ribitol), and cytidine-5′-monophosphate-N-acetyl-β-d-neuraminic acid (CMP-Neu5Ac), respectively, in consonance with expectations based on the diagnosis. In conclusion, a novel, semi-quantitative method was established for the analysis of nucleotide sugars that can be applied to diagnose several genetic glycosylation disorders in fibroblasts and beyond. [ABSTRACT FROM AUTHOR]

Metformin (MET) and sitagliptin (STG) are widely used as the first-line and long-term oral hypoglycemic agents for managing type 2 diabetes mellitus (T2DM). However, the current lack of convenient and rapid measurement methods poses a challenge for individualized management. This study developed a point-of-care (POC) assay method utilizing a miniature mass spectrometer, enabling rapid and accurate quantification of MET and STG concentrations in human blood and urine. By combining the miniature mass spectrometer with paper spray ionization, this method simplifies the process into three to four steps, requires minimal amounts of bodily fluids (50 μL of blood and 2 μL of urine), and is able to obtain quantification results within approximately 2 min. Stable isotope-labeled internal standards were employed to enhance the accuracy and stability of measurement. The MS/MS responses exhibited good linear relationship with concentration, with relative standard deviations (RSDs) below 25%. It has the potential to provide immediate treatment feedback and decision support for patients and healthcare professionals in clinical practice. [ABSTRACT FROM AUTHOR]

At present, the National Metrology Institute of Japan provides six national primary pH buffers under the Japan Calibration Service System. Each batch of these buffers is certified by the primary pH method using a Harned cell. On the basis of these primary buffers, the designated laboratories supply the secondary and working pH standards using a high-precision pH meter. This paper provides an estimate of the batch-to-batch reproducibility of the primary pH standard production based on the history of the certification of primary carbonate buffers in NMIJ. This buffer, which was chosen as the subject of the study because of the relative difficulty of its measurements (and thus a greater dispersion of results), is nominally the 0.025 mol kg−1 equimolal solution of disodium carbonate and sodium hydrogen carbonate. As its pH value is significantly affected by the purity of the reagents used, the evaluation of their source materials is made by both pH measurements and acidimetric gravimetric back titrations. Considering the experimentally determined pH reproducibility of ca. 0.010, potential risks to the pH accuracy are discussed when using recipe-based carbonate pH standards. [ABSTRACT FROM AUTHOR]

Antarctic seaweeds are vital components of polar marine ecosystems, playing a crucial role in nutrient cycling and supporting diverse life forms. The sulfur content in these organisms is particularly interesting due to its implication in biogeochemical processes and potential impacts on local and global environmental systems. In this study, we present a comprehensive characterization of seaweed collected in the Antarctic in terms of their total sulfur content and its distribution among different classes of species, including thiols, using various methods and high-sensitivity techniques. The data presented in this paper are unprecedented in the scientific literature. These methods allowed for the determination of total sulfur content and the distribution of sulfur compounds in different fractions, such as water-soluble and proteins, as well as the speciation of sulfur compounds in these fractions, providing valuable insights into the chemical composition of these unique marine organisms. Our results revealed that the total sulfur concentration in Antarctic seaweeds varied widely across different species, ranging from 5.5 to 56 g kg−1 dry weight. Furthermore, our investigation into the sulfur speciation revealed the presence of various sulfur compounds, including sulfate, and some thiols, which were quantified in all ten seaweed species evaluated. The concentration of these individual sulfur species also displayed considerable variability among the studied seaweeds. This study provides the first in-depth examination of total sulfur content and sulfur speciation in brown and red Antarctic seaweeds. [ABSTRACT FROM AUTHOR]

Comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC × GC–MS) has great potential for analyses of complicated mixtures and sample matrices, due to its separation power and possible high resolution. The second component of the measurement results, the mass spectra, is reproducible. However, the reproducibility of two-dimensional chromatography is affected by many factors and makes the evaluation of long-term experiments or cross-laboratory collaborations complicated. This paper presents a new open-source data alignment tool to tackle the problem of retention time shifts — with 5 different algorithms implemented: BiPACE 2D, DISCO, MSort, PAM, and TNT-DA, along with Pearson's correlation and dot product as optional methods for mass spectra comparison. The implemented data alignment algorithms and their variations were tested on real samples to demonstrate the functionality of the presented tool. The suitability of each implemented algorithm for significantly/non-significantly shifted data was discussed on the basis of the results obtained. For the evaluation of the "goodness" of the alignment, Kolmogorov–Smirnov test values were calculated, and comparison graphs were generated. The DA_2DChrom is available online with its documentation, fully open-sourced, and the user can use the tool without the need of uploading their data to external third-party servers. [ABSTRACT FROM AUTHOR]

The present paper discusses the use of a high-concentration-capacity tool, HiSorb, to investigate the impact of capsule material on the aroma profile of espresso-brewed coffee. The specific high-concentration-capacity probe used is characterized by a sorbent volume (63 μL) intermediate between the solid-phase microextraction (SPME) fiber (0.6 μL) and the stir-bar sorptive extraction rod (126 μL). The extraction performance of the HiSorb was compared, in terms of both absolute signal and compound coverage, with both an equivalent sorbent (polydimethylsiloxane) and a divinylbenzene/carboxen/polydimethylsiloxane SPME fiber using both targeted and untargeted approaches. The HiSorb showed superior extraction compared with the SPME fibers. The HiSorb was then optimized in terms of extraction time and temperature and used to investigate the volatile profile of 23 espresso-brewed coffees prepared with capsules made of different materials—aluminum, compostable, and aluminum multilayer pack—prepared using a refillable capsule. Comprehensive two-dimensional gas chromatography equipped with a reverse fill/flush flow modulator and coupled to mass spectrometry was used to obtain a chromatographic fingerprint of the volatile profile of the brewed coffee. The data were aligned and compared using a tile-based approach, and the results were obtained by performing raw data mining within the same software platform. The data mining enabled the extraction of informative features responsible for the differentiation between the different capsule materials, showing a significant depletion in aroma intensity in the compostable capsule. [ABSTRACT FROM AUTHOR]

Nucleic acid testing technology has made considerable progress in the last few years. However, there are still many challenges in the clinical application of multiple nucleic acid assays, such as how to ensure accurate results, increase speed and decrease cost. Herein, a three-way junction structure has been introduced to specifically translate analytes of loop-mediated isothermal amplification to a catalytic hairpin assembly. For different analyses, a well-optimized nucleic acid circuit can be directly applied to detection, through only one-component replacement, which only not avoids duplicate sequence design but also saves detection cost. Thanks to this design, multiple and logical analysis can be easily realized in a single reaction with ultra-high sensitivity and selectivity. In this paper, Mycoplasma pneumoniae and Streptococcus pneumoniae can be clearly distinguished from the clinical mixed sample with negative control or one analyte in one tube single fluorescence channel. The fair experimental results of actual clinical samples provide a strong support for the possibility of clinical application of this methodology. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy (SERS) has been widely used in the field of therapeutic drug monitoring (TDM) because of its powerful fingerprinting capability. In this paper, we used an in situ synthesis method to anchor Ag nanoparticles (AgNPs) on the surface of MIL-101(Cr) to obtain MIL-101(Cr)@Ag. Owing to the large specific surface area and ultra-high porosity of MIL-101(Cr)@Ag, we developed a method for the determination of chlorpromazine hydrochloride (CPZ) and aminophylline (AMP) in human serum by using it as a solid-phase extraction sorbent and SERS substrate. The label-free TDM-SERS method was able to evaluate the levels of CPZ and AMP in serum samples with detection limits as low as 8.91 × 10–2 µg/mL and 3.4 × 10–2 µg/mL, respectively. In addition, influencing factors including sample solution pH, AgNO3 concentration, drug adsorption time, and the amount of sample solution were optimized. This protocol provides a new method with good selectivity, stability, reproducibility, homogeneity, and sensitivity for the determination of small-molecule drug content in serum samples. This label-free TDM-SERS method will help to achieve rapid individualized dosing regimens in clinical practice and has potential applications in the field of TDM. [ABSTRACT FROM AUTHOR]

Organic field-effect transistors (OFETs) have been proposed beyond three decades while becoming a research hotspot again in recent years because of the fast development of flexible electronics. Many novel flexible OFETs-based devices have been reported in these years. Among these devices, flexible OFETs-based sensors made great strides because of the extraordinary sensing capability of FET. Most of these flexible OFETs-based sensors were designed for biological applications due to the advantages of flexibility, reduced complexity, and lightweight. This paper reviews the materials, fabrications, and applications of flexible OFETs-based biosensors. Besides, the challenges and opportunities of the flexible OFETs-based biosensors are also discussed. [ABSTRACT FROM AUTHOR]

Parkinson's disease is a health-threatening neurodegenerative disease of the elderly with clinical manifestations of motor and non-motor deficits such as tremor palsy and loss of smell. Alpha-synuclein (α-Syn) is the pathological basis of PD, it can abnormally aggregate into insoluble forms such as oligomers, fibrils, and plaques, causing degeneration of nigrostriatal dopaminergic neurons in the substantia nigra in the patient's brain and the formation of Lewy bodies (LBs) and Lewy neuritis (LN) inclusions. As a result, achieving α-Syn aggregate detection in the early stages of PD can effectively stop or delay the progression of the disease. In this paper, we provide a brief overview and analysis of the molecular structures and α-Syn in vivo and in vitro detection methods, such as mass spectrometry, antigen–antibody recognition, electrochemical sensors, and imaging techniques, intending to provide more technological support for detecting α-Syn early in the disease and intervening in the progression of Parkinson's disease. [ABSTRACT FROM AUTHOR]

Supply shortage for the development and production of preventive, therapeutic, and diagnosis tools during the COVID-19 pandemic is an important issue affecting the wealthy and poor nations alike. Antibodies and antigens are especially needed for the production of immunological-based testing tools such as point-of-care tests. Here, we propose a simple and quick magnetic nanoparticle (MNP)–based separation/isolation approach for the repurposing of infected human samples to produce specific antibodies and antigen cocktails. Initially, an antibody cocktail was purified from serums via precipitation and immunoaffinity chromatography. Purified antibodies were conjugated onto MNPs and used as an affinity matrix to separate antigens. The characterization process was performed by ELISA, SDS-PAGE, electrochemistry, isothermal titration calorimetry, and LC-Q-TOF-MS/MS analyses. The MNP-separated peptides can be used for mass spectrometry–based as well as paper-based lateral flow assay diagnostic. The exploitation of the current workflow for the development of efficient diagnostic tools, specific treatments, and fundamental research can significantly impact the present or eventual pandemic. This workflow can be considered as a two birds, one stone–like strategy. [ABSTRACT FROM AUTHOR]

Structural determination of N-glycans by mass spectrometry is ideally performed by negative ion collision-induced dissociation because the spectra are dominated by cross-ring fragments leading to ions that reveal structural details not available by many other methods. Most glycans form [M – H]- or [M + adduct]- ions but larger ones (above approx. m/z 2000) typically form doubly charged ions. Differences have been reported between the fragmentation of singly and doubly charged ions but a detailed comparison does not appear to have been reported. In addition to [M + adduct]- ions (this paper uses phosphate as the adduct) other doubly, triply, and quadruply charged ions of composition [Mn + (H2PO4)n]n- have been observed in mixtures of N-glycans released from viral and other glycoproteins. This paper explores the formation and fragmentation of these different types of multiply charged ions with particular reference to the presence of diagnostic fragments in the CID spectra and comments on how these ions can be used to characterize these glycans. [ABSTRACT FROM AUTHOR]

Microplastics are a widespread contaminant found not only in various natural habitats but also in drinking waters. With spectroscopic methods, the polymer type, number, size, and size distribution as well as the shape of microplastic particles in waters can be determined, which is of great relevance to toxicological studies. Methods used in studies so far show a huge diversity regarding experimental setups and often a lack of certain quality assurance aspects. To overcome these problems, this critical review and consensus paper of 12 European analytical laboratories and institutions, dealing with microplastic particle identification and quantification with spectroscopic methods, gives guidance toward harmonized microplastic particle analysis in clean waters. The aims of this paper are to (i) improve the reliability of microplastic analysis, (ii) facilitate and improve the planning of sample preparation and microplastic detection, and (iii) provide a better understanding regarding the evaluation of already existing studies. With these aims, we hope to make an important step toward harmonization of microplastic particle analysis in clean water samples and, thus, allow the comparability of results obtained in different studies by using similar or harmonized methods. Clean water samples, for the purpose of this paper, are considered to comprise all water samples with low matrix content, in particular drinking, tap, and bottled water, but also other water types such as clean freshwater. [ABSTRACT FROM AUTHOR]

Desorption electrospray ionization (DESI) mass spectrometry is an emerging technology for direct therapeutic drug monitoring in dried blood spots (DBS). Current DBS methods require manual application of small molecules as internal standards for absolute drug quantification. With industrial standardization in mind, we superseded the manual addition of standard and built a three-layer setup for robust quantification of salicylic acid directly from DBS. We combined a dioctyl sodium sulfosuccinate weave facilitating sample spreading with a cellulose layer for addition of isotope-labeled salicylic acid as internal standard and a filter paper for analysis of the standard-containing sample by DESI-MS. Using this setup, we developed a quantification method for salicylic acid from whole blood with a validated linear curve range from 10 to 2000 mg/L, a relative standard deviation (RSD%) ≤14 %, and determination coefficients of 0.997. The limit of detection (LOD) was 8 mg/L and the lower limit of quantification (LLOQ) was 10 mg/L. Recovery rates in method verification by LC-MS/MS were 97 to 101 % for blinded samples. Most importantly, a study in healthy volunteers after administration of a single dose of Aspirin provides evidence to suggest that the three-layer setup may enable individual pharmacokinetic and endpoint testing following blood collection by finger pricking by patients at home. Taken together, our data suggests that DBS-based quantification of drugs by DESI-MS on pre-manufactured three-layer cartridges may be a promising approach for future near-patient therapeutic drug monitoring. [ABSTRACT FROM AUTHOR]

An interview with Oluwatosin O. Dada, a research assistant professor at the University of Notre Dame in Indiana, is presented. Dada explains that his motivation to perform research into high-throughput capillary isoelectric focusing is its role in proteomics. Dada says he is impressed with the contributions of the Human Genome Project to the globalization of biomedical research. He shares that he wants to continue using his talent in analytical instrumentation to solve health problems.

An assembled-aptasensor based on Fe3O4@Au@Ag nanocomposites grafting onto the gold foil was prepared, which can be developed into a universal approach for sensitive and rapid detection of various pathogenic bacteria, such as Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium), Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), Pseudomonas aeruginosa (P. aeruginosa), and Shigella flexneri (S. flexneri). Firstly, the gold foil paper was modified with thiolated capture probe and SERS tag in proportion, and at the same time, the specific thiolated aptamer probe for corresponding pathogenic bacteria was fixed with Fe3O4@Au@Ag nanocomposites. An obvious Raman signal can be subsequently increased about 106 times by the external electromagnetic field enhancement at the "hot spots" caused by the hybridization of aptamer and capture probe. But in the presence of target pathogenic bacteria, Raman intensity will decrease as Fe3O4@Au@Ag nanocomposites are dissociated from gold foil. Thus, all of the concentrations of the six kinds of pathogenic bacteria both in PBS and liquorice extract showed an obvious negative linear correlation with the Raman intensity of SERS tag in the range of 10–107 CFU/mL with detection limits were all lower than 10 CFU/mL. And there was no significant difference between our method and the plate counting method. Besides, the assembled-aptasensor had superior specific recognition ability even in the mixed interfering bacteria. Our study showed that this assembled-aptasensor had good specific detection ability to a variety of foodborne pathogens based on magnetic field-assisted SERS technique, which can be used for rapid and sensitive detection of a variety of pathogens in complex substrates. [ABSTRACT FROM AUTHOR]

In this paper, a novel electrochemical sensor was constructed for the detection of purine bases. Ultrafine carbide nanocrystals confined within porous nitrogen-doped carbon dodecahedrons (PNCD) were synthesized by adding molybdate to ZIF-8 followed by annealing. With MoC-based PNCDs (MC-PNCDs) as the carrier, gold nanoparticles (AuNPs) were deposited on the electrode surface via potentiostatic deposition as the promoter of electron transfer, forming a AuNPs/MC-PNCDs/activated glassy carbon electrode (AGCE) sensor. MC-PNCDs had a large specific surface area, which combined with the excellent electrocatalytic activity of AuNPs, synergistically improved the electrocatalytic activity. The morphology and structure of the electrode surface modifier were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray photoelectron spectroscopy, infrared spectroscopy, X-ray diffraction, nitrogen adsorption–desorption analysis, and electrochemical characterization. Under the optimal conditions, the linear detection range of guanine (G) and adenine (A) was 0.5–160.0 μM, and the detection limits (S/N=3) were 72.1 and 69.6 nM, respectively. AuNPs/MC-PNCDs/AGCE was successfully constructed, and was used to simultaneously detect G and A with high sensitivity and selectivity. Moreover, the sensor was successfully used to detect G and A in herring sperm DNA samples. [ABSTRACT FROM AUTHOR]

Planar monolayer microreactor arrays (PMMRAs) make droplet-based numerical measurements and statistical analysis cheap and easy. However, PMMRAs are typically produced in complex microfluidic devices and, moreover, still requires stringent control to reduce droplet loss during heating. In this paper, a simple, reliable, and flexible method for fabricating PMMRAs in a 96-well plate is described in detail by using simple materials and low-cost equipment. The partitioned droplets spontaneously assemble into PMMRAs in the plates, and this distribution is maintained even after incubation. This is advantageous for in situ analysis based on an individual droplet in droplet digital loop-mediated isothermal amplification (ddLAMP) and does not require the transfer of positive droplets. Precise and reproducible quantification of classical swine fever virus (CSFV) extracts was executed in these PMMRAs to verify its availability. Our results demonstrate that the proposed approach not only provides a flexible and controllable execution scheme for droplet-based nucleic acid quantification in resource-limited laboratories but also opens new perspectives for numerous analytical and biochemical applications using droplets as versatile plastic microreactors. [ABSTRACT FROM AUTHOR]

The continuing pursuit for a healthy life has led to the urgent need for on-site analysis. In response to the urgent needs of on-site analysis, we propose a novel concept, called lab at home (LAH), for building automated and integrated total analysis systems to perform chemical and biological testing at home. It represents an emerging research area with broad prospects that has not yet attracted sufficient attention. In this paper, we discuss the urgent need, challenges, and future prospects of this area, and the possible roadmap for achieving the goal of LAH has also been proposed. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is one of the endocrine-disrupting chemicals which might cause reproductive and endocrine system diseases, and poses a serious threat to the ecosystem and human health. This paper reports an ultrasensitive sensor for trace BPA detection employing fluorescence resonance energy transfer (FRET) between modified upconversion nanoparticles (UCNPs) and tetramethylrhodamine. To circumvent the problems of low luminous efficiency of FRET and low sensitivity of sensor, the upconversion nanoparticles with very strong fluorescence efficiency were prepared and quantitatively modified. Results showed that the concentrations of amino groups and streptavidin were 43 nmol/mg and 6.12 μg/mg on the surface of the UCNPs, respectively. Under the optimal detection conditions, the peak intensity of UCNPs at 547 nm was linear with the logarithm of the BPA concentration with the detection limit of 0.05 ng/mL. Without complicated pre-processing, the recoveries were in general between 91.0 and 115.0% in tap water, river water, and disposable paper cup water. Therefore, the proposed sensor is suitable for effective sensing of trace BPA in water samples.ᅟ [ABSTRACT FROM AUTHOR]

Supercritical fluid chromatography (SFC), which employs pressurized carbon dioxide as the major component of the mobile phase, has been known for several decades but has faced a significant resurgence of interest in the recent years, thanks to the development of modern instruments to comply with current expectations in terms of robustness and sensitivity. This review is focused on the recent literature, specifically since the introduction of modern systems but in relation to older literature, to identify the changing trends in application domains. Typically, natural products, bioanalysis, food science, and environmental analyses are all strongly increasing. Together with reduced extra-column volumes in the instruments, the advent of sub-2-μm particles and superficially porous particles in the stationary phases is favoring ultra-high-performance SFC (UHPSFC) allowing for improved resolution and faster analyses, but without the constraints of viscous liquids encountered in ultra-high-performance liquid chromatography (UHPLC). Hyphenation to mass spectrometry is also more frequent and opened the way to new application domains, and raises different issues from liquid chromatography mobile phases, especially due to decompression of carbon dioxide. It is also shown that the frontiers between SFC and HPLC are fading, as switching from one method to the other, even within the course of a single analysis, is facilitated my modern instruments. The present review is not intended to be exhaustive but rather giving a snapshot of recent trends in supercritical fluid chromatography, based on the observation of about 500 papers published in English-written peer-reviewed journals from 2014 to 2018.ᅟ [ABSTRACT FROM AUTHOR]

Novel spherical polymer nanoparticles were synthesized by hyperbranched polyethylenimine (hPEI) and 6-hydroxy-2-naphthaldehyde (HNA) via Schiff base reaction (one-pot reaction), which had great advantages in water solubility and green synthesis. Meanwhile, probe PEI-HNA could quickly detect Cu2+ in the range of 0–60 μM in 30 s with the detection limit of 243 nM. The fluorescence of PEI-HNA-Cu2+ could be recovered by the addition of S2− in 50 s with the detection limit of 227 nM. Based on the excellent optical properties, PEI-HNA has been used in the bioimaging of living cells with excellent cell penetrability and low toxicity. More importantly, PEI-HNA has been doped into filter paper, hydrogel, and nanofibrous film to prepare solid-phase sensors, displaying rapid response and excellent sensitivity. Moreover, the low-cost and simple preparation of these sensors offers great potential and possibilities for industrialization, which could help accelerate the development of sensors in environmental and biological fields. [ABSTRACT FROM AUTHOR]

This paper describes initially the application of the Tyndall effect (TE) of metal–organic framework (MOF) materials as a colorimetric signaling strategy for the sensitive detection of pyrophosphate ion (PPi). The used MOF NH2-MIL-101(Fe) was prepared with Fe3+ ions and fluorescent ligands of 2-amino terephthalic acid (NH2-BDC). The fluorescence of NH2-BDC in MOF is quenched due to the ligand-to-metal charge transfer effect, while the NH2-MIL-101(Fe) suspension shows a strong TE. In the presence of PPi analyte, the MOFs will undergo decomposition because of the competitive binding of Fe3+ by PPi over NH2-BDC, resulting in a significant decrease in the TE signal and fluorescence restoration from the released ligands. The results demonstrate that the new method only requires a laser pointer pen (for TE creation) and a smartphone (for portable quantitative readout) to detect PPi in a linear concentration range of 1.25–800 μM, with a detection limit of ~210 nM (3σ) which is ~38 times lower than that obtained from traditional fluorescence with a spectrophotometer (linear concentration range, 50–800 µM; detection limit, 8.15 µM). Moreover, the acceptable recovery of PPi in several real samples (i.e., pond water, black tea, and human serum and urine) ranges from 97.66 to 119.15%. [ABSTRACT FROM AUTHOR]

In this paper, we establish an in situ visualization analysis method to image the spatial distribution of metabolites in different parts (sclerotium, coremium) and different microregions of Cordyceps cicadae (C. cicadae) to achieve the in situ visual characterization of tissues for a variety of metabolites such as nucleosides, amino acids, polysaccharides, organic acids, fatty acids, and so on. The study included LC–MS chemical composition identification, preparation of C. cicadae tissue sections, DEDI-MSI analysis, DESI combined with Q-TOF/MS to obtain high-resolution imaging of mass-to-charge ratio and space, imaging of C. cicadae in positive–negative ion mode with a spatial resolution of 100 μm, and localizing and identifying its chemical compositions based on its precise mass. A total of 62 compounds were identified; nucleosides were mainly distributed in the coremium, L-threonine and DL-isoleucine, and other essential amino acids; peptides were mainly distributed in the sclerotium of C. cicadae; and the rest of the amino acids did not have a clear pattern; sugars and sugar alcohols were mainly distributed in the coremium of C. cicadae; organic acids and fatty acids were distributed in the nucleus of C. cicadae more than in the sclerotium, and the mass spectrometry imaging method is established in the research. The mass spectrometry imaging method established in this study is simple and fast and can visualize and analyse the spatial distribution of metabolites of C. cicadae, which is of great significance in characterizing the metabolic network of C. cicadae, and provides support for the quality evaluation of C. cicadae and the study of the temporal and spatial metabolic network of chemical compounds. [ABSTRACT FROM AUTHOR]

Target-based drug discovery technology based on cell membrane targets has gained significant traction and has been steadily advancing. However, current methods still face certain limitations that need to be addressed. One of the challenges is the laborious preparation process of screening materials, which can be time-consuming and resource-intensive. Additionally, there is a potential issue of non-specific adsorption caused by carrier materials, which can result in false-positive results and compromise the accuracy of the screening process. To address these challenges, this paper proposes a target-based cell membrane affinity ultrafiltration technology for active ingredient discovery in natural products. In this technique, the cell membranes of human lung adenocarcinoma epithelial cells (A549) with a high expression of epidermal growth factor receptor (EGFR) were incubated with candidate drugs and then transferred to an ultrafiltration tube. Through centrifugation, components that interacted with EGFR were retained in the ultrafiltration tube as "EGFR-ligand" complex, while the components that did not interact with EGFR were separated. After thorough washing and eluting, the components interacting with EGFR were dissociated and further identified using LC–MS, enabling the discovery of bioactive compounds. Moreover, the target-based cell membrane affinity ultrafiltration technology exhibited commendable binding capacity and selectivity. Ultimately, this technology successfully screened and identified two major components from the Curcumae Rhizoma-Sparganii Rhizoma (CS) herb pair extracts, which were further validated for their potential anti-tumor activity through pharmacological experiments. By eliminating the need for laborious preparation of screening materials and the potential non-specific adsorption caused by carriers, the development of target-based cell membrane affinity ultrafiltration technology provides a simplified approach and method for bioactive compounds discovery in natural sources. [ABSTRACT FROM AUTHOR]