查看更多>>摘要：? 2021Escherichia coli O157:H7 is a major cause of fresh vegetable-associated infections that can threaten human health. A method for rapidly detecting food-borne pathogens should be developed for safe food management. A clustered regularly interspaced short palindromic repeats (CRISPR)-based detection method has the potential to greatly advance biosensing technology through its high sensitivity and specificity. In this study, we developed a rapid, sensitive, and visualized method of detecting E. coli O157:H7 (stx2 gene) based on a loop-mediated isothermal amplification (LAMP)-CRISPR/Cas12a system. The developed method was able to rectify the common false-negative results produced by LAMP, and the detection limit was 1.22 × 100 CFU/mL in pure culture. Furthermore, the LAMP-CRISPR/Cas12a system using filtration enrichment successfully detected 4.80 × 100 CFU/g of E. coli O157:H7 in romaine lettuce without pre-microbial enrichment culture. Consequently, the LAMP-CRISPR/Cas12a system is a useful technique for rapid and sensitive detection of E. coli O157:H7 in fresh products.
查看更多>>摘要：? 2022 Elsevier B.V.Congenital red and green color blindness is the most X-linked recessive disorder in humans caused by deletions or gross structural rearrangements of the visual pigment gene array that lead to altered the functions of visual pigments in their retina differ from normal. The incidence is about 7–10% in male and close association of X-linked recessive disorders (such as: hemophilia A, hemophilia B, duchenne muscular dystrophy). However, the traditional genetic analysis methods are time-consuming and low-efficiencies. Therefore, the purpose of the study is to develop a rapid method for genotyping of red and green pigment genes. We describe herein the first method for simultaneous evaluation of ten exons in the red and green pigment genes for genetic analysis. A forward specific primers with identifiable universal fluorescent multiplex PCR (FSIUFM-PCR) method utilized one universal primer (containing two universal non-human sequences) and forward specific primers in the multiplex PCR reaction system for simultaneously fluorescent labeling of eleven gene fragments (ten exons in red and green pigment genes and one internal standard). All the PCR products were analyzed on capillary electrophoresis with short-end injection, which had the advantage of high resolution and rapid separation. Of all 80 detected individuals, 7 subjects with color vision deficiencies (including 3 subjects only had red exons 1–5, 4 subjects had a specific red-green or green-red hybrid gene and 73 subjects with normal color vision). All genotyping results showed good agreement with DNA sequencing data. This method provided a better potential technique for genotyping and identifying of red and green pigment genes. In addition, FSIUFM-PCR method will be useful in many fields, such as diagnosis of diseases, analysis of polymorphisms and quantitative assay.
查看更多>>摘要：? 2022 Elsevier B.V.The Box-Behnken response surface design together with the individual desirability functions were used to develop the new and greenish sample preparation procedure of coffee brews prior to their multielement (Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn) analysis by inductively coupled plasma optical emission spectrometry (ICP OES). The developed procedure required only 2-fold dilution of the samples with a 1.8 mol L?1 HNO3 solution and then, the sonication of the resulting samples solutions for 8 min at room temperature. The proposed method was precise (0.6–7.5% as RSD), true (relative errors changing from ?5.2% to +4.6%) and guaranteed the limits of detection (LODs) of the studied elements between 0.1 and 5 ng g?1. Finally, this simplified ICP OES based method was applied for the multielement analysis of brews of different Arabica coffees as well as those prepared with seldomly reported devices, i.e., dripper, slow dripper, French press, aeropress and syphon.
查看更多>>摘要：? 2022 Elsevier B.V.Post-printing treatment is a promising means of enhancing the performance of devices manufactured using conventional three-dimensional printing (3DP) technologies. In this study we developed a post-printing solution foaming process—involving respective treatment with formic acid (60%, v/v) and sodium bicarbonate (5%, w/v) solutions to generate CO2 as a foaming agent—to increase the surface roughness and porosity of the polyamide 6 (PA6) monolithic packing in a multimaterial fused deposition modeling 3D-printed solid phase extraction (SPE) column, thereby enhancing the extraction of Mn, Co, Ni, Cu, Zn, Cd, and Pb ions from complicated real samples prior to their determination using inductively coupled plasma mass spectrometry. After optimizing the column fabrication process, the solution foaming treatment process, the extraction conditions, and the automatic analytical system, the 3D-printed SPE column incorporating the solution foaming–treated PA6 monolithic packing extracted these metal ions with 18.9- to 42.0-fold enhancements, relative to those of the as-printed column, with absolute extraction efficiencies all greater than 94.3% and method detection limits ranging from 0.2 to 7.7 ng L?1. We verified the reliability and applicability of this method through analyses of the tested metal ions in several reference materials (CASS-4, SLEW-3, 1643f, and 2670a) and spike analyses of seawater, river water, ground water, and urine samples. We conclude that post-printing treatment can dramatically improve the performance of 3D-printed analytical devices.
查看更多>>摘要：? 2022 The AuthorsA hybrid sensing system, which combines simultaneous cyclic voltammetric (CV) and UV–vis absorbance measurements using a commercial carbon screen-printed electrode and a set of optical fibres in disposable cuvettes, is proposed. The hybrid system approach was applied to 27 samples of recognized beer brands, improving the classification power as compared to only voltammetric or only spectrophotometric measurements. The developed partial least squares discriminant analysis (PLS-DA) model was able to discriminate between five types of beer (lager, marzen, black/stout, alcohol-free and white/ale). The model was also successfully applied to 28 beer samples of white-label brands sold in local supermarkets, demonstrating their similarity to recognized brand beers.
查看更多>>摘要：? 2022 Elsevier B.V.Oil and grease content in wastewater is used as an environmental monitoring parameter in the oil and gas industry to prevent serious pollution. Conventional oil and grease laboratory testing is time-consuming and necessitates the use of a hazardous chemical solvent, resulting in non-real-time test data and unnecessary chemical waste. On-site or real-time analysis can enable monitoring of oil and grease in wastewater before discharge to the environment from an operating plant, allowing immediate action to be taken to mitigate environmental impact before contamination spirals out of control. Bioluminescent whole-cell biosensors have been reported to have high sensitivity and selectivity in environmental samples, but only for a few traces of organic compounds such as polycyclic aromatics and naphthalene, allowing for faster analysis times. However, no evaluation of biosensor application for oil and grease (a mixture of hydrocarbons) detection in wastewater, which is critical in the oil and gas industry, has been published to date. Herein, the advantages, disadvantages, challenges, and limitations of using a whole-cell bioluminescent biosensor technology to measure oil and grease content in wastewater are carefully reviewed. This review attempts to bridge the knowledge gap between conventional laboratory methods and biosensor technology in terms of analytical challenges, identifying areas for improvement as well as real-world applications for oil and grease content detection in wastewater.
查看更多>>摘要：? 2022The detection of local anesthetic drugs is of great importance in the analysis of pharmaceutical, clinical and forensic samples. This paper reports a simple and sensitive potentiometric assay suitable for detecting general local anesthetics (LAs) of two types, namely: amino ester-anesthetics (procaine) and amino amide-anesthetics (lidocaine, articaine). As a detector, a new highly sensitive sensor based on a poly(vinyl chloride)-matrix membrane incorporating ion-pair complexes of protonated procaine with 2-[bis-octadecyl-sulfonic)-closo-decaborate is used. To improve the analytical characteristics of the sensor, the tetradodecylammonium – 2-[bis-octadecyl-sulfonic)-closo-decaborate associate as a lipophilic additive is proposed. The procedures for the synthesis of both electroactive membrane components are described. The dependence of potential response characteristics of the potentiometric system on the membrane composition, local anesthetic properties, and pH of the sample solutions is discussed. The difference in sensitivity and selectivity of the sensor was found to be responsible for the lipophilic property and pKa values of local anesthetic molecules. The developed sensor exhibited a near Nernstian response to cationic forms of procaine and some other anesthetics of higher lipophility, in particular lidocaine and articaine, over a wide linear concentration range. The limit of detection was varied from 2 × 10?8 to 5 × 10?7 μM, and it is the lowest value among the early published potentiometric analogs. The proposed method was successfully applied to the analysis of pharmaceutical formulations and spiked enzyme-free urine samples containing LAs at low concentration levels (0.5–100 μg mL?1). The recovery range (n = 5) was 98.0–101.5%, and the relative standard deviation was no more than 5.0%.
查看更多>>摘要：? 2022 Elsevier B.V.An efficient analytical method is developed using a porous sorptive polymer for thin film microextraction (PSP-TFME) of 8 model drugs from human urine samples. The analysis is conducted with ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The composition of the porous extraction phase, prepared on a stainless steel substrate, has been optimized for basic drugs of abuse and comprises methacrylic acid (MMA) as the monomer and ethylene glycol methacrylate (EGDMA) as the crosslinker. Factors influencing the analyte recovery and method precision (i.e., sample agitation, pH, extraction and washing time, desorption solvent and time) were assessed. The optimized method includes 5 min of direct immersion of the device into the sample, followed by a quick wash in water (1 min) to remove matrix interferences, and then 5 min in acidified methanol for analyte desorption. The extraction devices demonstrated acceptable inter-device variability (2.9–9.3 %RSD for 8 analytes and n = 10 devices) and no detectable difference between batches of devices (p > 0.05 for a 2-sample t-test). The analytical method was linear over a pharmacologically relevant range for each drug (i.e., 0.05–100 ng mL?1 for MDMA and methadone and 2.5–500 ng mL?1 for morphine with R2 varied from 0.9960 to 0.9996). A matrix effect study showed the devices have a high tolerance for complex variable biological matrices. The method also demonstrated excellent data accuracy in the range of 85.3–117.2% for intra-day assays and 88.8–117.9% for inter-day assays. The precision of the method was acceptable and in the range of 0.9–18.6% for intra- and 2.8–16.4% for inter-day assays, respectively.
查看更多>>摘要：? 2022 Elsevier B.V.In the process of tumorigenesis and development, cancer cells must integrate and respond to complex and dynamic signals in the tumor microenvironment. Nevertheless, simulating the original biomechanical and biochemical microenvironment of different cells in vitro is a fundamental challenge in studying synergistic effects. To address this issue, we have proposed a biomimetic multi-factor stimulation platform, which conveniently creates a two-dimensional matrix environment with controllable stiffness as biomechanical factor and can smoothly introduce biochemical cue. Our results indicated that the extracellular matrix (ECM) stiffness could enhance the cell stretching, which further lead to the amplification of cell-matrix adhesion and proliferation. And there existed obvious differences of endocytosis efficiency response of cells on matrix stiffness. Nanoparticles (NPs) with the same size and shape, but differs in electrical charges showed more uptake on harder matrix. Besides, the inorganic polyphosphates (polyP), which acts as energy storage and producer in the in-extracellular space, was proven to synergistically promote aforementioned cell biomechanical behaviors by increasing ATP metabolism for the first time. These results explored the impact of microenvironmental performance on the glioma mechanoresponses, and we believe this biomimetic multifactor stimulation method would exhibit a profound impact on researches of in vitro biomimetic cell culture and NPs-like drug phagocytosis.
查看更多>>摘要：? 2022 Elsevier B.V.Viscous microenvironments are ubiquitous in living organisms. An oxidative stress attack could cause the fluctuation of lymph or blood viscosity, which is closely related to many common diseases. However, the dual-function detection of reactive oxygen species and viscosity is still ineffective due to design defects. Herein, by rational linking a propeller-shaped triphenylamine rotator and a rigid planar anthracene, we report the first dual-ratiometric-response probe for ClO? and viscosity detection. The probe itself shows weak fluorescence background in low-viscous solution or at non-aggregate state, which can largely switch on its blue (414 nm) and yellow fluorescence (600 nm) respectively in response to ClO? and viscosity. Their sensing mechanisms were elucidated through the interruption of FRET and TICT processes for ClO? and viscosity detection, respectively. In addition to its mitochondria targeting ability, TPP-AN was employed for mitochondrial viscosity and ClO? imaging in HeLa cells, providing a potentially useful probe for clinical assays.
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