查看更多>>摘要：? 2022 Elsevier B.V.In this study, we designed a surface plasmon resonance (SPR) biosensors based on molecular imprinting to detect low amounts of thrombin directly in a short time, both in thrombin aqueous solutions and in patient serum samples. For this purpose, the thrombin imprinted and non-imprinted SPR biosensors were prepared by integrating the synthesized thrombin imprinted and non-imprinted nanoparticles on the allyl mercaptan modified gold SPR chip surface. The kinetic studies were performed with a thrombin concentration range from 0.1 to 400 pM with a detection limit of approximately 0.017 pM in thrombin aqueous solution. Morever, the limit of detection was found to be 0.033 pM in patient serum samples. When the selectivity of the thrombin imprinted SPR biosensors was compared with the competing molecules as bovine serum albumin and lysozyme, it was showed that the thrombin was 4.58 times and 3.99 times more selective than the bovine serum albumin and lysozyme molecules, respectively. The shelf life and reusability of the designed SPR biosensor showed that there was a 12.93% decrease in the performance according to the kinetic analyzes that performed after 8 months. In addition, thrombin detection from the patient serum samples was performed using both SPR biosensor and the enzyme-linked immunosorbent assay methods, and were calculated recoveries.
查看更多>>摘要：? 2022Coextraction of different groups of analytes is vital for saving sample volumes and simplifying analytical procedures in bioanalysis. Conventionally, coextraction was achieved by using multi-extraction systems with different supported liquid membranes (SLMs). However, the different membrane solvents tended to diffuse into the aqueous solutions and the other SLM to reach distribution equilibrium during extraction process, causing the system instability. In this work, a stable multi-extraction system (integration of liquid-phase microextraction and electromembrane extraction, LPME/EME) based on the identical supported semi-liquid membrane (SsLM) was developed. Principally, the state of distribution equilibrium of the membrane solvent (polypropylene glycol with molecular weight 4000) in SsLM could be reached at the beginning of extraction, which enhanced the coextraction stability. With this multi-extraction system, acidic and basic analytes were simultaneously extracted from practical biological samples. The extraction recoveries of the six model drugs in undiluted urine samples were over 70%. Followed by LC-MS/MS, the limits of quantification (LOQs) were in the range of 5–10 ng mL?1. The multi-extraction system using the identical SsLM in this study shows promising potential in construction of other stable multi-extraction systems (e.g., LPME/LPME and EME/EME) in the future, which will greatly benefit the group separation of analytes in complicated biological samples.
查看更多>>摘要：? 2022 The AuthorsMicroRNAs (miRNAs) are important diagnostic and prognostic biomarkers for various tumors. Currently, many diagnostic systems have been developed to detect miRNAs, but simple techniques for detecting miRNAs are still required. Recently, we reported that the expression of miRNA-135b is upregulated in gastric epithelial cells during gastric inflammation and carcinogenesis. Our aim was to develop an in vitro diagnostic platform to analyze the expression of gastric cancer-related biomarkers in the blood. The diagnostic platform comprised an isothermal amplification-based lateral flow biosensor (IA-LFB) that enables easy diagnosis of gastric cancer through visual observation. In this platform, trace amounts of biomarkers are isothermally amplified through rolling circle amplification (RCA), and the amplified product is grafted to the LFB. The performance of the IA-LFB was confirmed using RNAs extracted from in vitro and in vivo models. The platform could detect target miRNAs within 3 h with excellent sensitivity and selectivity. In particular, the IA-LFB could detect the overexpression of gastric cancer-related markers (miRNA-135b and miRNA-21) in RNAs extracted from the blood of patients with various stages (stages 1–4) of gastric cancer compared to that in healthy volunteers. Therefore, IA-LFB is a simple and sensitive in vitro diagnostic system for detecting gastric cancer-related biomarkers and can contribute to the early diagnosis and prognosis monitoring of gastric cancer. Furthermore, this technology can be applied to systems that can detect multiple biomarkers related to various diseases (such as infectious and genetic diseases).
查看更多>>摘要：? 2022 Elsevier B.V.Lab-In-Syringe direct immersion single drop microextraction is proposed as an automated sample pretreatment methodology and coupled online to HPLC with fluorescence detection for the determination of fluoroquinolones in environmental waters. For the first time, a drop of a natural deep eutectic solvent (NADES), synthesized from hexanoic acid and thymol, has been used as an extractant in automated single-drop microextraction. The extraction procedure was carried out within the 5 mL void of an automatic syringe pump. A 9-position head valve served the aspiration of all required solutions, air, waste disposal, and hyphenation with the HPLC instrument. Sample mixing during extraction was done by a magnetic stirring bar placed inside the syringe. Only 60 μL of NADES were required omitting toxic classical solvents and improving the greenness of the proposed methodology. By direct injection, linear working ranges between 0.1 and 5 μg L?1 were achieved for all fluoroquinolones. The limit of quantification values and enrichment factors ranged from 20 ng L?1 to 30 ng L?1 and 35 to 45, respectively. Accuracies obtained from the analysis of spiked surface water and wastewater treatment plant effluent analysis at two concentration levels (0.5 and 4 μg L?1) ranged from 84.6% to 119.7%, with RSD values typically <3%.
查看更多>>摘要：? 2022 The AuthorsA monolith of poly(methacrylic acid-co-ethylene glycol dimethacrylate) has been immobilised to a nitrocellulose strip by radical photopolymerisation to be used in the extraction of psychoactive substances in biological fluids. Codeine, methylone, amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, butylone, norketamine, ketamine, heroin, cocaine, lysergic acid diethylamide and fentanyl were employed as model drugs and final extracts were analysed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Polymerisation parameters were adjusted in order to obtain a stable and homogeneous layer of monolith onto the nitrocellulose strip. The resulting sorptive phase was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. Extraction conditions were investigated by the evaluation of sample pH, extraction and desorption times and desorption solvent volume, providing enrichment factor values ranging from 5.3 to 39.9. The proposed methodology provided limit of quantification values from 0.013 μg L?1 for methylone to 0.057 μg L?1 for amphetamine, and recoveries from 64 to 120%. Urine and serum certified reference materials were employed in the validation of the proposed methodology, providing results statistically comparable. The developed approach is simple and straightforward for the determination of psychoactive substances in urine and serum samples.
查看更多>>摘要：? 2022 Elsevier B.V.Differential scanning calorimetry (DSC) technology has been proven to be able to detect the purity of chemical reference substances, but there are few studies on its applicability to volatile organic compounds. In this study, the purity of a volatile deuterated compound (benzene-d6) was successfully assessed by the DSC combined with quantitative nuclear magnetic resonance (qNMR), in which the qNMR determined the content of benzene (as an isotopic impurity). The result was verified by the mass balance method combined with gas chromatography-mass spectrometry (GC-MS), in which the GC-MS determined the content of benzene. The results showed that the purity value of benzene-d6 was 994.1 mg g?1 ± 4.1 mg g?1, at the 95% confidence interval, which is equivalent to the value of 994.8 mg g?1 ± 1.2 mg g?1 from the mass balance method combined with GC-MS. It was proved that the DSC combined with qNMR can be used to quantify the purity of volatile deuterated compounds. For volatile compounds without isotopic impurities, they can be directly quantified by DSC. It should be noted that volatile compounds must be fully solidified under low temperature conditions to ensure the reliability of the results.
查看更多>>摘要：? 2022 Elsevier B.V.β-cyclodextrin/graphene oxide (GO-β-CD) was applied for dispersive micro-solid phase extraction (DMSPE) of uranyl ions (UO22+) from water samples and their determination by energy-dispersive (EDXRF) and total-reflection X-ray fluorescence spectrometry (TXRF). The structure of GO-β-CD was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The results of batch adsorption experiment indicate that the maximum recoveries for UO22+ ions are observed at pH 4.5. The Langmuir isotherm model fits the adsorption data, which stands for the chemisorption mechanism. The obtained adsorption capacity of 87.7 mg g?1 indicates a great potential of the synthesized adsorbent in the UO22+ ions preconcentration. The GO-β-CD exhibits high resistance to high ionic strength (up to 2 mol L?1), indicating that high salinity samples can be treated with the evaluated preconcentration procedure. The obtained limit of detection values were 0.40 μg L?1 for the EDXRF and only 0.014 μg L?1 for TXRF analysis. The accuracy of the method was verified by analyzing certified reference material (spring water NIST-SRM 1640a) and spiked water samples (mineral, lake, river, and artificial sea water).
查看更多>>摘要：? 2022 Elsevier B.V.Heterostructured construction is regarded as a valuable approach to improve photoelectrochemical (PEC) performances. Herein, porous hollow NiS@NiO spheres were prepared derived from the Ni(TCY) MOFs precursor. Photoactive TiO2 was coupled with as-prepared NiS@NiO to form a close heterojunction interface of NiS@NiO/TiO2. NiS@NiO/TiO2 modified ITO electrode (NiS@NiO/TiO2/ITO) displayed fiercely enhanced photocurrent response, which was 4687-fold than that of NiS@NiO/ITO (0.008 μA) and 8.5-fold than that of TiO2/ITO (4.41 μA), respectively. Remarkable PEC property could be ascribed to the hollow NiS@NiO spheres with thin-shell structure provided there is a larger active surface area for harvesting the visible light. Most importantly, the p-n type NiS@NiO/TiO2 heterojunction could lead to generating more photo-excited charge carriers (e?/h+) and efficiently hinder the recombination of carriers, resulting in significantly augmented photocurrent output. Based on this outstanding PEC property, NiS@NiO/TiO2/ITO electrode fabricated sensing platform (BSA/anti-CEA/NiS@NiO/TiO2/ITO, BSA=Bovine serum albumin) exhibited high sensitivity for monitoring CEA (Carcinoembryonic antigen). Wide linear detection range was from 0.001 to 45 ng mL-1 and with a low detection limit of 1.67 × 10-4 ng mL-1 (S/N = 3). Prepared biosensors also showed good reproducibility, stability and had satisfying specificity. Thus, the proposed NiS@NiO/TiO2 heterostructured composite afforded well-design and synthesis strategy for constructing high-performance photoactive materials from MOFs-derivate.
查看更多>>摘要：? 2022Water pollution, as the remarkable environmental remediation issue, is a today worldwide concern. Cadmium ion (Cd2+) as a hazardous water pollutant is seriously detrimental to human health, food safety, and ecological areas. Hence, we successfully designed a simple detection array for monitoring of ultra-low levels of Cd2+ ion by combining the advantages of aptamer as a high sensitive and selective sensing probe and zeolitic imidazolate framework-8 (ZIF-8) as a superior fluorescence quenching inducer. To have a portable and on-site detection assay, the aptamer biosensing array (aptasensor) was designed by using a paper-supported substrate. The basis of the designed paper-supported aptasensor was the specific complexation of Cd2+ with the aptamer strand, adsorption of fluorescein-labeled complementary (FAM-CP) strand on the ZIF-8 surface, and fluorescence quenching of FAM molecule after the leakage of the injected target solution on the sample zone of the paper substrate to the detection part. A linear relationship was obtained between the Mean Gray Value index, as a criterion for the fluorescence quenching, and the Cd2+ concentration in the range of 0.1–120 pM with a detection limit of 0.076 pM. The aptasensor could detect Cd2+ in the diverse real sample, including tap water, milk, coffee, and human blood serum.
查看更多>>摘要：? 2022 Elsevier B.V.Flexible-type signal probes and their detection methods are increasingly being applied in biosensors. Among these, temperature-based signal probes represent a novel research direction. These sensors convert immunoassay signals into temperature signals, which are then detected using a thermometer or thermal infrared reader. However, from a physical viewpoint, we know that the temperature measured directly using a thermal infrared camera is the infrared radiance temperature, which is proportional to both the true temperature and emissivity. Herein, we design a novel sensing method that uses infrared radiance rather than true temperature as the signal probe. We convert the immunoassay to an infrared radiation temperature measurement by controlling an aluminum plate in constant temperature whose infrared radiation temperature varied significantly with immunoassay-based the amount of the target. We then develop two readout systems: one is based on a scientific-grade infrared camera, and the other uses a smartphone-based thermal camera, which is more portable, flexible, and can be used as an in-pocket sensor. The sensors are verified via detecting exemplary biomarker human IgG, and show excellent quantitative model performances in 0–100 ng mL?1 concentration range with the detection limit estimated as low as 0.54 ng mL?1. The excellent quantitative results demonstrate the powerful detection performance of this sensing method.
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