Talanta最新文献

With the advancement of flexible electronics, the demand for low-cost, high-performance flexible humidity sensors for wearable devices has increased significantly. However, commercial humidity sensors require complex preparation methods and are expensive. Therefore, we report polyvinyl alcohol/chitosan/nano carbon powder (PVA/CS/NCP) humidity-sensitive composite materials, which were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements. A resistive humidity sensor was fabricated using screen printing, and the device showed a good response at 33%RH-98%RH humidity, and at 98 % RH, the sensor achieved a response of 1.74. A fully printed field-effect transistor (FET) humidity sensor was prepared by integrating an ion gel transistor with a CS/PVA/NCP humidity-sensitive resistor to improve the response. The comparison reveals a significant improvement in the FET humidity sensor's response, reaching 6.27 at 98 % RH. In addition, both types of sensors exhibit less hysteresis and good repeatability. Lastly, we tested the constructed humidity sensors under non-contact and variable breathing conditions, laying the groundwork for future wearable applications.

Abnormal kinase expression affects phosphorylation in the human body, which is associated with numerous diseases, including cancer, diabetes mellitus, and Alzheimer's disease. In this study, we synthesized a highly stable, two-dimensional, luminescence-functionalized metal-organic framework with remarkable electrochemiluminescence (ECL) by immobilizing 9,10-Di(p-carboxyphenyl) anthracene (dca) on a zirconium cluster (dca-Zr₁₂) via a strong coordination bond between -COO⁻ and Zr⁴⁺. This novel and simple platform relies on the highly specific identification of phosphate molecules by the ultra-thin dca-Zr₁₂ nanoplate through carboxylate-Zr⁴⁺-phosphate chemistry. The ferrocene-labeled peptide substrate (Fc-S-Peptide) was phosphorylated in the presence of protein kinase A (PKA) and adenosine 5'-triphosphate (ATP), and the resulting phosphopeptide could subsequently be precisely captured by the zirconium sites of the dca-Zr₁₂-modified electrode and, eventually, quench the ECL and gain a signal-off state. This rapid and simple detection strategy was successfully employed to measure PKA activity, with a detection limit as low as 0.35 mU mL^-1. Based on the results, it exhibited high selectivity and can be applied for screening PKA inhibitors. The technique was subsequently applied to detect protein kinase activity in drug-stimulated MCF-7 cell lysates, demonstrating its potential for kinase-related investigations. Further, this platform could identify the activity of other kinase types with universal applicability.

Red tide events caused by Akashiwo sanguinea (A. sanguinea) pose a significant threat to ecosystems. However, studies that offer promising approaches for portable and onsite detection with precise identification of A. sanguinea remain insufficient. In this study, we developed an electrochemical biosensor (E-biosensor) for detecting A. sanguinea combined with cascade amplification strategies, termed TDW-E-biosensor. A predictive relationship was also established to predict algal cell density based on electrochemical signals. The experiment results showed that the TDW-E-biosensor was successfully applied for detecting A. sanguinea at the pre-outbreak stage and demonstrated excellent analytical performance, showing a low limit of detection (LOD) of 0.0676 fM and quantitation (LOQ) of 0.102 fM for the three-electrode system, and a low LOD of 6.873 fg μL^-1 and LOQ of 20.460 fg μL^-1 for the portable system. The accuracy of the TDW-E-biosensor was validated through comparison with droplet digital PCR (ddPCR) and Bland-Altman analysis, demonstrating a high level of agreement (a mean difference of 0.132 and a standard deviation of 0.184). The reliability of the predictive relationship was evidenced by controlled laboratory experiments and Bland-Altman analysis. The developed TDW-E-biosensor provides an innovative and promising tool for early warning efforts regarding harmful algae.

Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 12a (CRISPR/Cas12a) detection system is now widely used for nucleic acid detection and disease diagnosis. However, there are still fewer detections for single nucleotide polymorphisms (SNPs) and limited diversified detection systems for pathogen and SNP sites detection, which greatly limits their applications. Obviously, the development of a more diversified and convenient suite of detection tools is essential to unlock the full potential of CRISPR/Cas12a technology and to expand its applications across a wider range of scenarios. We have successfully developed an integrated CRISPR/Cas12a assay system. This system introduces crRNA during protein expression, reducing the number of steps and reaction time by adding only a fluorescent reporter gene and target DNA during subsequent detection. It enables on-site visualization of the assay in combination with a Recombinase polymerase amplification (RPA) reaction. Combined with the RPA reaction, we are able to rapidly detect African swine fever virus (ASFV) pathogens with high specificity. The system also enables genotyping of the SNP site of the porcine prolificacy-associated estrogen receptor (ESR) gene and the sheep prolificacy-associated Fecundity booroola (FecB) gene. Visualization is possible up to a final concentration of 3 nM, and effective differentiation of low concentrations within the concentration range of the assay. The integrated CRISPR/Cas12a assay system we developed has a robust design that ensures high-fidelity genotyping and pathogen detection are no longer restricted to the lab, allowing for rapid field analysis, which is crucial for timely interventions in agricultural and clinical settings. In addition, it has the advantages of low cost, easy operation and visualization of results.

The indicator amino acid oxidation (IAAO) technique estimates the physiological requirements for amino acids and proteins in living organisms, including humans. It involves monitoring urinary amino acids and exhaled CO₂ after ingesting 1-¹³C-labeled (carboxy-labeled) amino acids. The most common IAAO indicator amino acid is 1-¹³C-labeled phenylalanine ([1-¹³C]Phe). Its urinary concentration in test subjects ranges from below the detection limit to several μM. A simple analytical method for distinguishing trace amounts of [1-¹³C]Phe in urine from high levels of naturally occurring Phe is crucial for making IAAO tests easier. This study presents a simple and reliable approach for the simultaneous quantification of [1-¹³C]Phe and Phe in human urine using conventional GC-EI-MS. In this method, urinary phenylalanine is reacted with pentafluorobenzyl bromide in a single-phase solvent system of acetone-borate buffer without dehydration or desalting to form disubstituted pentafluorobenzyl (PFB) derivatives, which are then analyzed by GC-EI-MS (SIM). The Phe and [1-¹³C]Phe PFB derivative peaks eluted at the same retention time on the gas chromatogram but could be differentiated on the basis of fragment ions (m/z 434, 435) derived from the loss of the phenyl group ([M - 91]⁺). Correcting the interference of the m+1 isotope peak of Phe in the [M - 91] fragment (m/z 435) of [1-¹³C]Phe using the m/z 434 peak intensity and natural isotope ratio, both Phe and [1-¹³C]Phe could be quantified in the concentration range found in urine. The method was successfully applied to examine the temporal enrichment of [1-¹³C]Phe in urine samples obtained from IAAO subjects following the ingestion of a test meal containing [1-¹³C]Phe.

A simple and efficient effervescence-assisted salting-out assisted liquid-liquid extraction (EA-SALLE) method was developed for the rapid extraction of pyrethroid insecticides in fruit juices and herbal extracts. By integrating effervescence extraction with SALLE, the extraction and phase separation processes were conducted simultaneously, significantly simplifying the experimental procedure and reducing the extraction time to just 3 min. Key factors influencing the method's efficiency were systematically optimized. Combined with gas chromatography with an electron capture detector, enabled the determination of nine pyrethroid insecticides, demonstrating excellent linearity (R² > 0.99), low limits of detection (0.03-0.17 ng/mL), satisfactory accuracy (recoveries ranging from 83.0 % to 107.9 %), and good precision (RSD < 9.1 %). The proposed EA-SALLE method offers a simple, efficient, and cost-effective sample preparation technique. It is characterized by ease of operation, short extraction time, and high sensitivity, providing an effective tool for the monitoring and assessment of pesticide residues in complex samples.

Hydrogen peroxide (H₂O₂) plays a key role in a diverse array of cellular signaling pathways, which is closely related to plant health and physiological status. The accurate and efficient monitoring of H₂O₂ in living plant cells has attracted enormous interest. Herein, we developed an electrochemical-colorimetric dual-mode sensor based on the peroxidase-like activity of a polyacrylamide (PAM) -modified copper electrode (Cu-PAM), allowing for the in situ detection of H₂O₂ released from tomato leaves. The co-electrodeposition of unique combination of Cu and polyacrylamide, as well as the active site structure of Cu-centered peroxidases, can enhance adsorption performance by the hydrogen bonds between PAM with H₂O₂, which exhibited excellent electrochemical performance with a low limit of detection (LOD) of 0.0167 mM and a detection range of 0.05-25.31 mM. Meanwhile, a colorimetric signal output of the sensor that can be quantified from 1 μM to 70 μM with a LOD value of 0.33 μM. This work demonstrates a huge potential application prospect of the polyacrylamide-modified copper in the field of biosensors.

In this study, a rapid and simple semi-automatic emulsification liquid-liquid microextraction technique based on deep eutectic solvents was developed for determining strobilurin fungicides in food samples using high-performance liquid chromatography. Novel deep eutectic solvents formed as extractants by combining quaternary phosphates and fatty acids, eliminating the need for toxic solvents in liquid-phase microextraction. The extraction process was facilitated by an electric micropipette, which emulsified and injected the deep eutectic solvent-water mixture directly into the sample. The semi-automated approach enhanced extraction speed and efficiency while minimizing manual error. The sample and deep eutectic solvent mixture were emulsified immediately and separated within 15 min of standing. Only an electronic micropipette was used to achieve extraction and separation. The method demonstrated a linear range of 2-200 μg L^-1 with R² > 0.996 and a limit of detection of 0.6 μg L^-1. Recovery ranged from 73.0 % to 100.1 %, with relative standard deviations from 0.4 % to 6.1 %. The greenness of the method was validated through multiple assessment tools, including the Green Analytical Procedure Index, Analytical GREEnness metric for sample preparation, and Sample Preparation Metric of Sustainability. The emulsification liquid-liquid microextraction procedure, based on innovative solvents and electric micropipette technology, proved successful for application in water, juice, and vinegar samples and showed potential for broader use in pesticide residue analysis in food.

Resmetirom is the first innovative drug for the treatment of non-alcoholic steatohepatitis (NASH), and its two crystal forms, form I and form-2H₂O, were mentioned in the original patent. The commercially available crystal form of resmetirom was form I. However, the tablets were subject to temperature, pressure, and humidity, and may be converted to form-2H₂O, which affects the bioavailability and efficacy. Therefore, it is crucial to establish a suitable crystalline quantification method to examine the concentration of both crystalline forms in APIs and formulations. The main objective of this paper was to test the feasibility of PXRD, FTIR and Raman for quantitative analysis of form I content in API and formulation models. Commonly used methods to establish quantitative modelling were univariate and multivariate analyses, due to the overlapping peaks in the FTIR and Raman spectra of two forms, only the multivariate method, with partial least squares regression (PLSR), was used, both univariate and multivariate analysis were utilized in PXRD since it has distinct single peaks. In the multivariate models, the raw spectra are preprocessed to remove interfering information and spectral noise by nine commonly used pretreatment methods. According to the result of this study, all four calibration models could be applied to the quantitative analysis of form I in two models; however, Raman was found to be the most appropriate model for both API model (Y = 0.99523X+0.00300, R² = 0.9997, RMSECV = 9.32 %, RESEP = 0.29 %, RESEC = 0.19 %, LOD = 3.2819 %, LOQ = 9.9451 %, MSC pretreated) and formulation model (Y = 0.99456X+0.00331, R² = 0.9996, RMSECV = 1.14 %, RESEP = 0.39 %, RESEC = 0.01 %, LOD = 3.3098 %, LOQ = 9.1029 %, WT pretreated).

Given the threat posed by toluene to human health and environmental safety, real-time and efficient detection of toluene assumes paramount importance. However, the low chemical reactivity and structural similarity of benzene, toluene, and xylene (BTX) gases impede the attainment of highly selective toluene detection. Herein, palladium-loaded indium oxide nanospheres were successfully synthesized through a combination of solvothermal and post-reduction methods. And the sensor based on 0.75 wt% Pd-In₂O₃ exhibits the response to the concentration of 100 ppm toluene (R_a/R_g = 21) that is approximately four times better compared to pure indium oxide (R_a/R_g = 4) at their respective optimum operating temperatures. Moreover, this sensor exhibited enhanced sensing performance towards toluene, including a low operating temperature of 160 °C, exceptional selectivity, and good stability. Furthermore, an investigation into the sensing mechanism of toluene by the Pd-In₂O₃-based sensor was conducted. The chemical and electron sensitization effects of palladium result in the more chemisorbed oxygen of the sensing material, which improves the toluene sensing performance by enhancing the reaction with more toluene molecules. Additionally, the moderate catalytic activation of toluene by palladium plays a crucial role in improving the selectivity. Overall, this work provides a basis for the rational design of metal oxide semiconductor sensors with catalytic properties for the highly selective detection of toluene.