查看更多>>摘要：Antibiotic residues have become a public health issues, the fast detection of tetracycline (Tc) in the environment is urgently required. In this work, Ti3C2 quantum dots (Ti(3)C(2 )QDs) and Europium ions jointly constructed a ratiometric fluorescence (FL) platform for the detection of Tc, based on synergistic impact of the Foster Resonance Energy Transfer (FRET) from Ti(3)C(2 )QDs to Eu3+ ions and the Antenna Effect (AE) between Tc and Eu3+ ions. And we proposed a ratiometric FL platform for detecting Tc with good linear response range (100-1000 uM) and low detection limit (48.79 nM). Meanwhile, we applied this platform to detect a serious of beta-diketone ligands of Eu3+ ions, demonstrating the platform's versatility for this category of chemical. Furthermore, based on the color changes of QDs@Eu3+ from blue to red at 365 nm ultraviolet light, an intelligent detection smart device was built for the visual semi-quantitative detection of Tc in actual samples. We proved the applicability of the device in complicated samples and the potential for rapid, sensitive, intuitive and point-of-care detection in the field of environment, food, pharmaceutical and agriculture. (c) 2022 Published by Elsevier B.V.
查看更多>>摘要：Nanocatalytic amplification of carbon dots is a new way to improve sensitivity. The preparation of the high catalytic activity and stable iron/nitrogen-doped carbon dot (CDBFe) sol and its application in apta-mer (Apt) assay have not been reported yet. In this paper, a simple hydrothermal procedure for the prepa-ration of CDBFe derived from Fe2+-2,2'-bipyridine complex has been developed. It is found that CDBFe has a strong catalytic effect on the indicator reaction of glyoxal (C2H2O2) reduction of HAuCl(4 )to produce gold nanoparticle (AuNP) probe with strong surface enhanced Raman scattering (SERS) at 1617 cm(-1), reso-nance Rayleigh scattering (RRS) effect at 370 nm and absorption (Abs) at 550 nm. A rapid and sensitive CDBFe catalytic amplification Apt method for SERS/RRS/Abs trimode detecting ultratrace lead ions was established, based on the Apt reaction mediated the nanocatalytic indicator reaction. The results show that the SERS intensity and Pb(II) concentration have a good linear relationship in the range of 1.3- 16 pM, and the detection limit is the lowest. In addition, Hg(II) and As(III) can also be measured by this naocatalytic amplification-Apt assay platform. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In order to prepare a kind of efficient fluorescence sensors for determination of cis-diol-containing flavo-noids, novel imprinted quantum dots for myricetin (Myr) were prepared based on boronate affinity-based template-immobilization surface imprinting. The obtained boronate affinity-based surface imprinted silica (imprinted APBA-functionalized CdTe QDs) was used as recognition elements. The quan-tum dots were used as signal-transduction materials. Under the optimum conditions, according to fluo-rescence quenching of imprinted APBA-functionalized CdTe QDs by Myr, the imprinting factor (IF) for Myr was evaluated to be 7.88. The result indicated that the boronate affinity functionalized quantum dots coated with imprinted silica were successfully prepared. The prepared imprinted APBA-functionalized CdTe QDs exhibited good sensitivity and selectivity for Myr. The fluorescence intensity was inversely pro-portional to the concentration of Myr in the 0.30-40 lM concentration range. And its detection limit was obtained to be 0.08 lM. Using the fluorescence sensors, the detection of Myr in real samples was successfully carried out, and the concentration of Myr in green tea and apple juice samples was evaluated to be 2.26 mg/g and 0.73 mg/g, respectively. The recoveries for the spiked green tea and apple juice samples were 95.2- 105.0% and 91.5-111.0%, respectively. This study also provides an efficient fluorescent detection method for cis-diol-containing flavonoids in real samples. (c) 2022 Elsevier B.V. All rights reserved.
Berrones-Guerrero, J. D.Frausto-Reyes, C.De la Torre-I, Manuel H.Ortiz-Morales, M....
8页
查看更多>>摘要：The polarization state of the excitation light used in two Raman systems was controlled to study its effect in the unpolarized Raman spectra of unstructured samples. Both systems work in different regions of the electromagnetic spectrum (NIR and visible). Four polarization states (linear, linear at 45 degrees and 90 degrees, and cir-cular) were used to excite liquid samples (ethanol, acetone, and their mixture). The results show that the Raman peaks intensities' ratio varies according to the polarization state of the excitation light. Peaks related to functional groups and C-H stretching modes increase their intensity when circular polarization (CP) is applied. The latter may help to study liquid mixtures with low concentrations. Different polarizing light states give a more detailed spectroscopic analysis since it gathers more structural information of the samples tested in this work with an undefined structure.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：As a kind of subcellular organelle, lipid droplets (LDs) play a critical role in the body's normal metabolism. LDs have gained increasing attention as a fluorescent photodynamic target site. Near-infrared (NIR) organic light-emitting luminescent materials, with aggregation-induced emission (AIE)-active feature, preeminent LD-imaging ability, and effective reactive oxygen species (ROS) production property, have been widely used for photodynamic therapy (PDT) in diagnostic therapeutics, but its application remains challenging. In the present work, three novel NIR organic compounds with AIE-active feature, namely, TPET-Is, TPET-Fu, and TPEF-Is, were developed and synthesized. These heteroaryl-bridged molecules possess a donor-donor-p-acceptor structure and strong intramolecular charge transfer character. These AIEgens are capable of high-fidelity LD imaging in living cells (Pearson's coefficient values: 0.94, 0.96, 0.97) due to their biocompatibility, good photostability, and strong lipophilicity (LogP values: 9.39, 7.89, 8.03), respectively. Moreover, they can be also applied in bright imaging the LDs of oil-rich plant tissues, such as those of sunflower seeds. The respective AIEgens TPET-Fu of these compounds can also produce ROS in the condition of white light to effectively kill live Hela cells. The present study thus provides a potential strategy through heteroaryl-bridged molecular engineering for LD-targeted imaging and PDT application. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The effect of water, confinement and confined water on the proton transfer of 3,5-bis(2-hydroxyphenyl)1H-1,2,4-triazole (bis-HPTA) was investigated. Water alters the proton transfer process. At higher pH, an anion is formed in water and it undergoes intermolecular proton transfer and forms a keto tautomer. Confinement of molecule in b-cyclodextrin affects the intramolecular proton transfer. It also prevents the intermolecular proton transfer of the anionic form. In reverse micelle, the molecule resides in the interfacial region and interacts with bound water. The intermolecular hydrogen bond of the surfactants opens the intramolecular hydrogen bond in the weaker b -ring of bis-HPTA. It led to single tautomer emission from bis-HPTA. An increase in water amount enhances the relative amount of trans-enol, but predominantly tautomer emission is observed.(C) 2022 Published by Elsevier B.V.
查看更多>>摘要：Lysosomes are the acidic organelles in the cells that play an important role in intracellular degradation and other various cellular functions. The pH disturbance of lysosomes will result in the lysosomal dysfunction and many lysosomal related diseases. In this work, we reported a methoxy-based covalent organic framework (TAPB-DMTP-COF) that a novel pH-responsive fluorescent probe for lysosomal pH imaging in cells. The prepared TAPB-DMTP-COF presented regular crystal structure, low toxicity and good pH responsive property. The rich imine structure in the material enabled pH-responsive properties of the TAPB-DMTP-COF and made it exhibited pH-dependent fluorescence response. Good detection linearity for pH measurements in aqueous solution was achieved by this probe. Moreover, the TAPB-DMTP-COF can be used for the selective lysosomal pH imaging. Confocal fluorescence imaging results demonstrated that the pH fluctuations (from 4.0 to 7.4) and the pH changes in lysosomes can be effectively monitored in situ by the developed probe. This study may provide a new avenue for the intracellular pH sensing, deep study and understanding about the mechanism of diseases related to abnormal lysosomal pH.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Fly ash (-FA) from seven typical power plants in Shanxi province (North China) were collected to explore the effect of carbon residues (-CR) structures on their burnout characteristic. Burnout characteristic is expressed by the loss on ignition (LOI) content in fly ash. Raman spectroscopy and Fourier Transform infrared (FTIR) spectroscopy are used to characterize the structure of CR. The structure parameters include Raman parameter (the full width at half maxima (FWHM) ratio of D-1 and G, I-D1/I-G) and FTIR parameter (asymmetric stretching intensity ratio of CH2 and CH3 groups, A(CH2)/A(CH3)). Three samples come from circulating fluidized bed (CFB), and four samples are from pulverized coal boilers (PC). Then two types of power plants are numbered from one to three according to the increasing degree of feed coal (-C) metamorphism. The CFB-1-FA, CFB-2-FA, and CFB-3-FA have loss on ignition (LOI) of 9.01%, 16.4%, and 21.6% respectively, while the LOI contents are 1.99%, 4.62%, 23.7%, and 5.00% for the PC-1-FA, PC 2-FA, PC-3-FA, and PC-4-FA. The results show that carbon residues in the PC fly ash mainly have the shorter and branched aliphatic side chains with lower A(CH2)/A(CH3) value. While carbon residues in the CFB fly ash have relatively longer aliphatic chains, and intramolecular aromatization is the main reaction during combustion. The I-D1/I-G of the CFB carbon residues are generally higher than it for the PC samples, indicating a more ordered structure. Oxygen-deficient environment and the longer residence time at temperature around 900 & DEG;C in the CFB boiler promote the ordering progress of the CR. The ordered CR suppresses its burnout and leads to an increase LOI content in fly ash. In turn, sufficient oxygen and temperature around 1200 & DEG;C in the PC boiler make the CR further oxidize and decompose. The CR become less ordered and are prone to burn out, resulting in a reduction of the LOI content. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Ilyas, QanitaWaseem, Muhammad TahirJunaid, Hafiz MuhammadKhan, Zulfiqar Ali...
13页
查看更多>>摘要：Rapid detection of 2,4,6-trinitrophenol (TNP) in real samples has recently attained considerable attention from the perspective of national security, human health, and environmental safety. In this context, costeffective and convenient detection of TNP explosive was accomplished through two new fluorescein based sensors F2 and F3. Sensors displayed effective fluorescence quenching response towards TNP in the aqueous medium. Highly sensitive fluorescence detection of TNP explosive (detection limit, 0.73 (F2) and 1.7 nM (F3)) was governed by ground-state charge transfer complex formation, facilitated by favorable H-bonding between sensor and TNP explosive. Fluorescence quenching mechanism for the detection of TNP explosive was investigated through UV-Visible absorption, dynamic light scattering (DLS), density functional theory (DFT) calculations, the Benesi-Hildebrand, and Job's plots. Advantageously, sensors displayed selective and immediate colorimetric recognition of TNP explosive. Importantly, sensors exhibited quick response time towards TNP even in the presence of potential interferences that make them highly suitable for practical applications. Sensors were successfully applied for fluorescent and colorimetric detection of TNP explosive in industrial water samples and fabrication of logic gates. Further, convenient contact mode and instant surface sensing of TNP explosive were achieved through the fabrication of fluorescent strips and explosive responsive test kits.(c) 2022 Elsevier B.V. All rights reserved.
Hussain, SaddamJunaid, Hafiz MuhammadWaseem, Muhammad TahirRauf, Waqar...
14页
查看更多>>摘要：New quinoline based fluorescent sensors 4 and 5 were rationally synthesized that exhibited excellent aggregation induced emission (AIE) in an aqueous medium. High fluorescence emission of sensors was accompanied by a noticeable redshift in their absorption and emission spectra that corresponds to the formation of J-aggregates. An AIE feature of sensors 4 and 5 was used for selective detection of Fe3+ and 4-NP in an aqueous medium that is attributed to the involvement of intermolecular charge transfer (ICT). The interaction mechanism of sensors with Fe3+ and 4-NP was investigated through H-1 NMR titration, Jobs plots, dynamic light scattering (DLS), and DFT analysis. The fluorescence quenching response of sensors 4 and 5 displayed distinguished linear behavior with the concentrations of Fe3+ and limits of detection (LOD) were calculated to be 15 and 10 nM, respectively. Further, LOD of sensors 4 and 5 for 4-NP (7.3 and 4.1 nM, respectively) was very low compared to previously reported sensors. Moreover, sensors' coated test strips were fabricated for solid-supported detection of Fe3+ and 4-NP. Sensors were successfully applied for the detection and quantification of Fe3+ and 4-NP in real water samples. Additionally, sensors were used for the determination of trace amounts of Fe3+ in the human serum sample. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
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