Analyst最新文献

Due to the unique advantages of mimicking natural enzymes, nanozymes have received ever-growing interest in a wide range of fields including analytical chemistry in the past two decades. Exploring novel kinds of nanozymes with efficient active sites has always been one of the most important and hot topics in nanozyme-related research so far, especially in portable monitors. Herein, zeolitic imidazolate framework-8 (ZIF-8) incorporated with an organometallic iridium(III) complex as a new active site denoted as Irppy-ZIF-8 obtained via a one-pot coordination reaction between the iridium solvent complex and 2-methylimidazole is reported as an efficient peroxidase (POD)-like nanozyme. Importantly, due to the specific inhibition effects of triazine pesticides on the POD-like activities of this novel nanozyme, a portable acetylcholinesterase (AChE)-free colorimetric sensor via a smartphone apart from a UV-vis spectrometer to detect triazine pesticides in real vegetable sample analysis is further successfully proposed in this work. It should be noted that this work could not only open up a new avenue to explore novel kinds of nanozymes from organometallic complexes as active sites, but also promote the progress in emerging applications of nanozymes in visual and portable sensors in the future.

Detection of carcinogenesis-related miRNAs presents significant challenges due to their low abundance and high specificity, necessitating highly sensitive and reliable analytical methods. Herein, we propose a generic in situ electrochemical biosensor for the sensitive and effective detection of miRNAs by rationally integrating an entropy-driven DNA circuit (EDC) with a tetrahedral scaffold. The key advancement of this work is the implementation of tetrahedral DNA nanostructures (TDNs) as both a scaffold and substrate for the EDC directly on the electrode surface. TDNs, which are readily decorated with ordered orientation and well-controlled spacing, enhance hybridization efficiency and facilitate essential structural interactions within the EDC, achieving a performance comparable to that of homogeneous liquid-phase reactions. Identifying a target miRNA is achieved with complementary probes that trigger a cascade of structural rearrangements leading to the immobilization of numerous biotin-labeled signal strands on the electrode surface. This accumulation of biotinylated strands ensures that the initial interfacial hybridization event is subsequently amplified and translated into electrochemical signals via cascaded signal amplification. The resulting electrochemical signals are directly proportional to the concentration of the target miRNA, offering a highly sensitive detection platform with a detection limit as low as 74 aM and a dynamic range spanning from 100 aM to 100 pM. The biosensor's performance is validated using biological samples derived from B[a]PDE-exposed cells, where significantly elevated miR-96 levels are detected, consistent with qRT-PCR results. This demonstrates the potential of the proposed biosensor for early cancer diagnosis and monitoring of cancer-related miRNA biomarkers.

Although combinational antiretroviral therapy has been proven highly effective, it suffers from drug–drug interactions, drug resistance and adverse reactions with long-term use. The introduction of novel drugs in antiretroviral therapy proposes newer treatment options. However, drug safety and their potential interactions after long-term therapy remain largely unexplored. In this study, the induction potential of bictegravir on efflux transporters at the protein level was assessed by quantifying the transporters using an LC-MS/MS-based method. A surrogate peptide approach was used for the simultaneous determination of P-gp, BCRP and MRP1 transporter proteins in rat peripheral blood mononuclear cells. The previously developed Excel-based ProteoExcel^TP tool was utilized for selecting surrogate peptides corresponding to the target transporters. Moreover, ProteoExcel^TP was integrated with a novel MRM prediction capability for predicting MRM transitions of selected surrogate peptides. The surrogate peptides LLSGQALK (415.2 → 716.4), SSLLDVLAAR (522.8 → 288.1) and EDLDLVLK (472.7 → 685.3) were selected for P-gp, BCRP and MRP1 transporter proteins, respectively. The peptides LLSGQALK, SSLLDVLAAR and EDLDLVLK were eluted at 5.4, 7.0 and 4.1 min, respectively. The findings of the study revealed that bictegravir could significantly induce BCRP transporter after one week of its administration to Sprague-Dawley rats. This finding can be utilized in the future to prevent transporter-mediated drug–drug interactions involving bictegravir. Moreover, the addition of MRM prediction feature to ProteoExcel^TP enhanced its applicability in mass spectrometry-based targeted proteomics. The developed LC-MS/MS-based quantitation method for determining clinically relevant efflux transporters will be useful in investigating the induction potential of other drugs.

Nicotinamide adenine dinucleotide is a crucial coenzyme in cellular metabolism and is implicated in various diseases. This work introduces an electrochemical bioanalytical method utilizing solution-phase Candida boidinii formate dehydrogenase (CbFDH) for detecting its oxidized form (NAD⁺) in human blood plasma samples. The detection mechanism involves the catalytic conversion of NAD⁺ to NADH, facilitated by CbFDH in the presence of formate. This NADH is then quantified by electrochemical measurements at disposable carbon screen-printed electrodes. The reaction is completed within one minute. The assay exhibits a linear response range from 3.74 μM to 2.00 mM, a sensitivity of 8.98 ± 0.18 μA mM⁻¹, and a limit of detection (3s_b/m) of 1.12 μM. It demonstrates selectivity against common interferences found in plasma samples, including glucose, urea, creatinine, guanosine 5′-monophosphate, cytidine 5′-monophosphate, flavin adenine dinucleotide, adenosine 5′-triphosphate, and lactate, with interference levels below 5% relative to the unperturbed NAD⁺ signal. Recovery studies showed 98.0–104.4% recoveries, with further validation against a colorimetric alcohol dehydrogenase assay confirming accuracy in plasma samples.

A paper-based potentiometric sensor integrated with a polymeric hydrogel has been developed for sodium ion (Na⁺) determination in human urine. The construction of an all-solid-state ion selective electrode (s-ISE) and an all-solid-state reference electrode (s-RE) on a photo paper substrate was achieved using an inkjet printing method. For s-ISE fabrication, carbon nanotubes (CNTs) and gold nanoparticles (AuNPs) were printed on the substrate as a nanocomposite solid contact. A polymeric hydrogel containing lithium acetate (CH₃COOLi) was then prepared and used as an intermediate layer to improve the adhesion between the ion selective membrane (ISM) and the AuNP/CNT solid contact, leading to enhanced detection sensitivity. The printed s-RE consisted of a pseudo silver/silver chloride electrode (p-Ag/AgCl) coated with a polymeric hydrogel containing KCl to improve the potential stability of the sensor. Under the optimal conditions, the hydrogel-integrated paper-based potentiometric sensor provided a response toward Na⁺ over a linear range of 10⁻⁷ M to 1 M with a near Nernstian slope of 56.42 ± 0.68 mV per decade. This sensor exhibited fast response, good sensitivity, and reasonable selectivity for Na⁺ measurement. Furthermore, the developed sensor was effectively applied for the detection of Na⁺ in urine samples with high accuracy. The presented work can be considered as a good addition to the growing field of potentiometric analytical platforms suitable for large-scale production using inkjet printing technology.

Herein, two new or overlooked features of ZIF-90 were identified and investigated. Imidazole-2-carboxaldehyde is fluorescent, but its fluorescence in ZIF-90 is quenched by an ACQ effect. ZIF-90 can enhance the fluorescence of Cy5, but quench that of 6-FAM. The applicability of the two newly identified features in biosensing was explored.

Recent advances in nucleic acid (NA) detection techniques have significantly enhanced the diagnosis of diseases caused by a range of pathogens. These NA-based methods that target specific gene sequences for identification offer high specificity. Despite the effectiveness of polymerase chain reaction (PCR), its requirement for sophisticated laboratory settings and expensive equipment restricts its accessibility, particularly in resource-limited settings. As an alternative, isothermal nucleic acid amplification methods are highly sought after due to their rapid, sensitive, and specific detection ability. Among these, loop mediated isothermal amplification (LAMP) stands out due to its simplicity, reliability, and cost-effectiveness. LAMP operates without the need for varied temperature cycles, employing a simple heating block to maintain a constant temperature, thus facilitating onsite rapid testing. In LAMP, the detection step is critical as it shows the outcome of the assay. In order to make the LAMP technique user-friendly and applicable for large scale testing, it is critical to have visual detection where the results can be observed with the naked eye. This review focuses on recent developments of LAMP visualization techniques, including the more common fluorescence, turbidity, and gel electrophoresis methods, as well as innovations in colorimetric techniques applying novel transduction methods such as nanoparticles and digital tools. Additionally, various practical applications of LAMP are discussed.

Carotenoids are known for their antioxidant and vision protection roles, with dietary supplements often promoted for eye health. An initial trial, the European Nutrition in Glaucoma Management (ENIGMA), assessed macular pigment optical density (MPOD) and other ocular parameters before and after supplementing glaucoma patients with macular pigment (MP) carotenoids. The trial confirmed significant improvements in clinical ocular health. Blood, containing all major dietary carotenoids, serves as an efficient medium for in vivo analysis of carotenoids. Raman spectroscopy, an effective analytical tool, was used to measure the impact of supplementation on serum carotenoid levels and their correlation with MPOD and other ocular responses. Serum samples from baseline and 18-month supplemented participants were analysed. An inverse relationship was found between the percentage change in Raman intensity over the supplementation period and baseline Raman serum measurements, indicating greater relative benefits for people with low MPOD/serum carotenoids pre-supplementation. Partial least squares regression (PLSR) was employed to analyse the spectra after pre-processing, and the loadings reflected the carotenoid content and structural profile. MPOD results correlated at all eccentricities, with a coefficient of determination (R²) of 0.62–0.92 and %Root mean squared error of <44%. Structural, functional, and perceptual parameters also showed good correlation with serum Raman measurements. The results support the ENIGMA trial conclusions, and suggest strategies for optimizing patient responses to supplementation based on baseline carotenoid levels. Additionally, Raman spectroscopy of serum carotenoids shows significant potential as a simple and reliable method for investigating macular pigment carotenoids and assessing patient health.

Herein, we report on a polyamine receptor L1 bearing pyrene fluorogenic groups for the optical assessment of the non-opioid analgesic drug ketoprofen (KP). L1, composed of a diethylenetriamine moiety linked at its extremities to the 1 position of two pyrene units via methylene linkers, produced an emission at 460 nm in 1 : 1 (v/v) water/ethanol mixture at pH 7, which can be attributed to the excimer formation between the two aromatic groups. In the presence of KP, a salt-bridging interaction between the carboxylate group of the analyte and the central ammonium group of L1 induced a redistribution of acidic protons in the polyamine chain, causing a marked increase in the emission. This optical signal was used to detect KP in aqueous media. Based on this observation, the properties of all-solid-state optodes with plasticized PVC membranes doped with L1 and deposited on an appropriate solid support material were further investigated. The best membrane contained 1 wt% of fully protonated L1, plasticized with DOS and doped with 3 equiv. of the TDMACl anion-exchanger, which detected KP in the 2 μM–0.1 mM range with a low influence of interfering ions. Furthermore, this membrane was applied for the assessment of the amount of KP in OkiTask, achieving an RSD of 2.1% and recovery of 102%. Moreover, the possibility to decrease the LOD of KP to 0.84 μM (0.21 mg L⁻¹) through the application of L1-based fluorescent sensor arrays and chemometrics was studied.