显示样式:     当前分类: 分析    当前期刊: All 导出
我的关注
我的收藏
您暂时未登录!
登录
  • A novel electrochemical sensor based on Cu@Ni/MWCNTs nanocomposite for simultaneous determination of guanine and adenine
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-11-20
    Dongyang Wang, Bintong Huang, Jie Liu, Xia Guo, Guzailinur Abudukeyoumu, Yang Zhang, Bang-Ce Ye, Yingchun Li

    A novel electrochemical sensing platform based on combination of multi-walled carbon nanotubes and copper-nickel hybrid nanoparticles (Cu@Ni/MWCNTs) was developed for simultaneous detection of guanine (G) and adenine (A). The Ni/MWCNTs and Cu@Ni/MWCNTs nanocomposites were characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). The electrochemical behaviors of G and A on the modified electrode were explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in phosphate buffer with pH 3.0. Under the optimal conditions, electrical signals were linear over the concentration ranges from 5.0 to 180 μM and 8.0 to 150 μM for simultaneous determination G and A with the detection limit as low as 0.35 μM and 0.56 μM (S/N=3), respectively. Furthermore, linear concentration ranges in individual determination are 1.0~180 μM and 2.0~150 μM with detection limits of 0.17 μM and 0.33 μM (S/N=3) for G and A, respectively. The sensor was successfully used to quantify G and A in real samples. The Cu@Ni/MWCNTs composite presented here can serve as a promising candidate for developing electrochemical sensor devices and plays an important role in widespread fields.

    更新日期:2017-11-20
  • Paper-based diagnostics in the antigen-depletion regime: high-density immobilization of rcSso7d-cellulose-binding domain fusion proteins for efficient target capture
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-11-20
    Eric A. Miller, Subha Baniya, Daniel Osorio, Yara Jabbour Al Maalouf, Hadley D. Sikes

    In this work, we report the development of a general strategy for enhancing the efficiency of target capture in immunoassays, using a bifunctional fusion protein construct which incorporates a substrate-anchoring moiety for the high-abundance immobilization of an antigen-binding domain. This approach was informed by the development of a pseudo first-order rate constant model, and tested in a paper-based assay format using a fusion construct consisting of an rcSso7d binding module and a cellulose-binding domain. These rcSso7d-CBD fusion proteins were solubly expressed and purified from bacteria in high molar yields, and enable oriented, high-density adsorption of the rcSso7d binding species to unmodified cellulose within a 30-second incubation period. These findings were validated using two distinct, antigen-specific rcSso7d variants, which were isolated from a yeast surface display library via flow cytometry. Up to 1.6 micromoles of rcSso7d-CBD was found to adsorb per gram of cellulose, yielding a local binder concentration of up to 760 μM within the resulting active material. At this molar abundance, target antigens are captured from solution with nearly 100% efficiency, maximizing the attainable sensitivity for any given diagnostic system.

    更新日期:2017-11-20
  • Porous silicon based photoluminescence immunosensor for rapid and highly-sensitive detection of Ochratoxin A
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-11-17
    Valerii Myndrul, Roman Viter, Maryna Savchuk, Nelya Shpyrka, Donats Erts, Daniel Jevdokimovs, Viesturs Silamiķelis, Valentyn Smyntyna, Arunas Ramanavicius, Igor Iatsunskyi

    A rapid and low cost photoluminescence (PL) immunosensor for the determination of low concentrations of Ochratoxin A (OTA) has been developed. This immunosensor was based on porous silicon (PSi) and modified by antibodies against OTA (anti-OTA). PSi layer was fabricated by metal-assisted chemical etching (MACE) procedure. Main structural parameters (pore size, layer thickness, morphology and nanograins size) and composition of PSi were investigated by means of X-Ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. PL-spectroscopy of PSi was performed at room temperature and showed a wide emission band centered at 680±20 nm. Protein A was covalently immobilized on the surface of PSi, which in next steps was modified by anti-OTA and BSA in this way a anti-OTA/Protein-A/PSi structure sensitive towards OTA was designed. The anti-OTA/Protein-A/PSi-based immunosensors were tested in a wide range of OTA concentrations from 0.001 upto 100 ng/ml. Interaction of OTA with anti-OTA/Protein-A/PSi surface resulted in the quenching of photoluminescence in comparison to bare PSi. The limit of detection (LOD) and the sensitivity range of anti-OTA/Protein-A/PSi immunosensors were estimated. Association constant and Gibbs free energy for the interaction of anti-OTA/Protein-A/PSi with OTA were calculated and analyzed using the interaction isotherms. Response time of the anti-OTA/Protein-A/PSi-based immunosensor toward OTA was in the range of 500–700 s. These findings are very promising for the development of highly sensitive, and potentially portable immunosensors suitable for fast determination of OTA in food and beverages.

    更新日期:2017-11-20
  • Hsa-miR-1587 G-quadruplex formation and dimerization induced by NH4+, molecular crowding environment and jatrorrhizine derivatives
    Talanta (IF 4.162) Pub Date : 2017-11-20
    Wei Tan, Long Yi, Zhentao Zhu, Lulu Zhang, Jiang Zhou, Gu Yuan

    A guanine-rich human mature microRNA, miR-1587, was discovered to form stable intramolecular G-quadruplexes in the presence of K+, Na+ and low concentration of NH4+ (25 mM) by electrospray ionization mass spectrometry (ESI-MS) combined with circular dichroism (CD) spectroscopy. Furthermore, under high concentration of NH4+ (100 mM) or molecular crowding environments, miR-1587 formed a dimeric G-quadruplex through 3’-to-3’ stacking of two monomeric G-quadruplex subunits with one ammonium ion sandwiched between the interfaces. Specifically, two synthesized jatrorrhizine derivatives with terminal amine groups could also induce the dimerization of miR-1587 G-quadruplex and formed 1:1 and 2:1 complexes with the dimeric G-quadruplex. In contrast, jatrorrhizine could bind with the dimeric miR-1587 G-quadruplex, but could not induce dimerization of miR-1587 G-quadruplex. These results provide a new strategy to regulate the functions of miR-1587 through induction of G-quadruplex formation and dimerization.

    更新日期:2017-11-20
  • Gold Leaf: From Gilding to the Fabrication of Disposable, Wearable and Low-cost Electrodes
    Talanta (IF 4.162) Pub Date : 2017-11-20
    Mauro Sérgio Ferreira Santos, Wilson Akira Ameku, Ivano Gebhardt Rolf Gutz, Thiago Regis Longo Cesar Paixão

    Gold is among the most used materials in electrocatalysis. Despite this, this noble metal is still too expensive to be used in the fabrication of low cost and disposable devices. In the present work, gold-leaf sheets, usually employed in decorative crafts and wedding candies, is introduced as an inexpensive source of gold. Planar-disc and nanoband gold electrodes were simply and easily manufactured by combining gold leaf and polyimide tape. The planar disc electrode exhibited electrochemical behavior similar to that of a commercial gold electrode in 0.2 mol·L−1 H2SO4; cyclic voltammetry of a 1 mmol·L−1 solution of potassium ferricyanide (K3[Fe(CN)6]) in 0.2 mol·L−1 KNO3, using this novel electrode, displayed an 80 mV difference between the oxidation and reduction peak potentials. The electrode also delivers promising prospects for the development of wearable devices. When submitted to severe mechanical deformation, this electrode exhibited neither loss of electrical contact nor significant variation in electrode response, even after fifteen bending and/or folding cycles. The thickness of the gold-leaf sheet facilitates the production of nanoband electrodes with behavior similar to that of ultramicroelectrodes. The electrode surface is easily renewed by cutting a thin slice off its end with a razor blade; this process led to limiting currents that were reproducible, presenting a relative standard deviation (RSD) of 3.8% (n=5).

    更新日期:2017-11-20
  • Bright-green-emissive nitrogen-doped carbon dots as a nanoprobe for bifunctional sensing, its logic gate operationand cellular imaging
    Talanta (IF 4.162) Pub Date : 2017-11-20
    Fangfang Du, Xiaojuan Gong, Wenjing Lu, Yang Liu, Yifang Gao, Shaomin Shuang, Ming Xian, Chuan Dong

    A fluorescent nanoprobe based on nitrogen-doped carbon dots (N-CDs) with green fluorescent emission have been fabricated through a facile one-step hydrothermal treatment using catechol and triethylene tetramine as precursors. The obtained N-CDs with excellent luminescent properties and superior biocompatibility have been applied for the development of a bifunctional sensor for the detection of Fe3+ and ascorbic acid (AA). Fe3+ that are tightly chelating the surface of N-CDs can induce fluorescence (FL) quenching of N-CDs through photo-induced electron transfer (PET). Meanwhile, the addition of AA serves to shelter the CDs effectively from being quenched by Fe3+ due to AA, as an antioxidant, enable easy-conversion of Fe3+ to reduced states (i.e. Fe3+ and Fe2+). The N-CDs are used as a facile and label-free “on-off-on” fluorescent nanoprobe for the determination of Fe3+ and AA with detection limits of 58.82 nM and 0.236 µM with the corresponding linear ranges of 25–200 µM and 25–300 µM, respectively. According to this phenomenon, an “AND” logic gate based on the novel N-CDs has been constructed. As-prepared N-CDs with negligible toxicity and perfect biocompatibility were expanded for cellular imaging and sensing Fe3+ and AA in living cell, which enlarges the application range of the N-CDs. Most importantly, the as-constructed fluorescent sensing system was successfully applied to detection of Fe3+ in tap water and the analyses of AA in fresh fruits with satisfactory results.

    更新日期:2017-11-20
  • Ultrasensitive and high specific detection of non-small-cell lung cancer cells in human serum and clinical pleural effusion by aptamer-based fluorescence spectroscopy
    Talanta (IF 4.162) Pub Date : 2017-11-20
    Yuhang Wu, Hong Zhang, Junfeng Xiang, Zhihua Mao, Gang Shen, Fengmin Yang, Yan Liu, Wei Wang, Ning Du, Jinghua Zhang, Yalin Tang

    Lung cancer is the leading cause of cancer-related deaths worldwide, and approximately 85% are diagnosed as non-small-cell lung cancer (NSCLC). However, efficient detection and diagnosis of NSCLC at early stage is still challenging. In this work, we developed a simple, ultrasensitive and high selective strategy for A549 human NSCLC cells detection based on combining the reorganization property of a novel cyanine dye 3,3′-di(3-sulfopropyl)−4,5,4′,5′-dibenzo-9-methyl-thiacarbocyanine triethylammonium salt (cy-M) to aptamer S6 G-quadruplex structure having specific affinity to NSCLC cells, which induced a dramatic fluorescence enhancement (~ 104 times). Moreover, this strategy was successfully used for detecting of A549 cancer cells in complex media such as human serum and clinical pleural effusion, which strong indicated that the proposed method could be applied for the early diagnosis of lung cancer.

    更新日期:2017-11-20
  • Novel approach in k0-NAA for highly concentrated REE Samples
    Talanta (IF 4.162) Pub Date : 2017-11-20
    M. Abdollahi Neisiani, M. Latifi, J. Chaouki, C. Chilian

    The present paper presents a new approach for k0-NAA for accurate quantification with short turnaround analysis times for rare earth elements (REEs) in high content mineral matrices. REE k0 and Q0 values, spectral interferences and nuclear interferences were experimentally evaluated and improved with Alfa Aesar Specpure Plasma Standard 1000 mg kg-1 mono-rare earth solutions. The new iterative gamma-ray self-attenuation and neutron self-shielding methods were investigated with powder standards prepared from 100 mg of 99.9% Alfa Aesar mono rare earth oxide diluted with silica oxide. The overall performance of the new k0-NAA method for REEs was validated using a certified reference material (CRM) from Canadian Certified Reference Materials Project (REE-2) with REE content ranging from 7.2 mg kg-1 for Yb to 9610 mg kg-1 for Ce. The REE concentration was determined with uncertainty below 7% (at 95% confidence level) and proved good consistency with the CRM certified concentrations.

    更新日期:2017-11-20
  • Carbon nanotubes magnetic hybrid nanocomposites for a rapid and selective preconcentration and clean-up of mercury species in water samples
    Talanta (IF 4.162) Pub Date : 2017-11-20
    Ana I. Corps Ricardo, Armando Sánchez-Cachero, María Jiménez-Moreno, Francisco J. Guzmán Bernardo, Rosa C. Rodríguez Martín-Doimeadios, Ángel Ríos

    Hybrid nanocomposites based on Fe3O4 magnetic nanoparticles (MNPs) coated with different types of carbon nanotubes (CNTs) have been studied for the first time as sorbent materials for magnetic solid phase extraction (MSPE) for mercury speciation analysis. Monomethylmercury (MMHg) was the target mercury species in water samples and the adsorption and desorption processes were optimized based on this species. Single-walled CNT-MNP showed higher adsorption capacity than double-walled or multi-walled CNTs. Then, the magnetic sorbent was retrieved with an external magnet and MMHg was selectively desorbed from it with dichloromethane (DCM) in two steps with vortex agitation. Inorganic mercury was removed during the desorption stage. The rapid adsorption and desorption equilibrium, the magnetic separation of the sorbent, and the simple and fast synthesis of CNT-MNPs without any additional modification of the CNTs simplified and shortened the extraction procedure. The extract was submitted to derivatization of the mercury species by ethylation (with an optional nitrogen stream evaporation of the organic phase) and injection into a gas chromatograph coupled to an atomic fluorescence detector (GC-pyro-AFS). The overall procedure provides the preconcentration of MMHg up to 150 times and the removal of inorganic mercury at the same time. The procedural limits of detection (LOD) and quantification (LOQ) were 5.4 and 17.9 pg mL−1, respectively. Moreover, magnetic nanocomposites can be reused at least 7 times without losing their efficiency. The methodology was validated in tap, dam and river water samples to evaluate the performance under real conditions with recoveries from 86 to 97% of spiked MMHg.

    更新日期:2017-11-20
  • An electrochemical aptasensor for the highly sensitive detection of 8-hydroxy-2′-deoxyguanosine based on the hybridization chain reaction
    Talanta (IF 4.162) Pub Date : 2017-11-20
    Li-Ping Jia, Li-Juan Wang, Rong-Na Ma, Lei Shang, Wei Zhang, Qing-Wang Xue, Huai-Sheng Wang

    In the present work a highly sensitive and selective aptasensor was developed for the determination of 8-hydroxy-2′-deoxyguanosine (8-OH-dG) based on the hybridization chain reaction (HCR) signal amplification. It was observed that the aptamer of 8-OH-dG could hybridize with the capture DNA immobilized on the gold electrode with a sticky tail left, which initiated the HCR and led to the formation of extended dsDNA structure on the electrode surface. Then the electroactive species ([Ru(NH3)6]3+, RuHex) intercalated into the dsDNA grooves to generate the amplified signal. However, in the presence of 8-OH-dG, the aptamer containing G-rich nucleic acid sequences would be induced to form a G-quadruplex structure, which made it impossible to continue the HCR. So the detection signal will significantly decrease. Under the optimal conditions, the peak current of RuHex was linear with the logarithm of 8-OH-dG concentration in the range from 10 pM to 100 μM with the detection limit of 2.5 pM. By integrating the merits of enzyme-free amplification power of the HCR and the inherent high sensitivity of the electrochemical technique, the prepared aptasensor not only showed high sensitivity for the detection of 8-OH-dG, but also exhibited good selectivity against to the uric acid, an important interferent in the urine sample. Particularly, the aptasensor was applied to detect 8-OH-dG in urine samples with satisfactory results.

    更新日期:2017-11-20
  • Novel synthesis of glucose functionalized magnetic graphene hydrophilic nanocomposites via facile thiolation for high-efficient enrichment of glycopeptides
    Talanta (IF 4.162) Pub Date : 2017-11-20
    Xiaoyan Feng, Chunhui Deng, Mingxia Gao, Guoquan Yan, Xiangmin Zhang

    High-efficient enrichment of glycopeptides prior to mass spectrometry is essential for glycoproteomics analysis. Hydrophilic interaction chromatography (HILIC) approach is a prominent strategy for glycopeptides identification. In this work, glucose functionalized magnetic graphene hydrophilic nanocomposite (MagG/Au/Glu) was synthesized as a novel HILIC material via a facile surface modification strategy. Different from previous click synthesis of saccharides-functionalized materials, glucose was easily thiolated via Traut's reagent and then immobilized on the materials via efficient Au-S coupling, greatly simplifying the synthesis process. Combining the rapid magnetic response, huge surface area from graphene and excellent hydrophilicity from glucose, MagG/Au/Glu nanocomposites afforded convenience of the operation and affinity for glycopeptides. Thus, the nanocomposites exhibited superior performance of high sensitivity, selectivity and reusability in glycopeptide enrichment from tryptic digests of standard glycoprotein HRP. Encouragingly, with the usage of MagG/Au/Glu nanocomposites, a total of 305 glycopeptides assigned to 108 glycoproteins were identified from complex real sample human serum, indicating a great potential for the application of glycoproteomics research.

    更新日期:2017-11-20
  • A dual-targeting DNA tetrahedron nanocarrier for breast cancer cell imaging and drug delivery
    Talanta (IF 4.162) Pub Date : 2017-11-20
    Xiaoting Liu, Lina Wu, Lei Wang, Wei Jiang

    To enhance efficacy of chemotherapy and achieve real-time imaging of cancer cells, it is crucial to develop nanocarriers with targeted drug delivery capacity and fluorescence property for cancer theranostics. Herein, a dual-targeting DNA tetrahedron nanocarrier (MUC1-Td-AS1411) was constructed for breast cancer cell imaging and targeted drug delivery. This nanocarrier consisted of three components: (i) DNA tetrahedron core for multivalent conjugation of function ligands and loading doxorubicin (Dox); (ii) activatable MUC1 aptamer probe (MUC1-probe), formed by the hybridization of MUC1 aptamer sequence with fluorophore extended from one vertex and complementary sequence with quencher, for targeting and imaging MUC1 protein on cytomembrane; (iii) AS1411 aptamer, which was hybridized to the overhang on three vertexes via prolonged sequence, for binding to nucleolin. Firstly, MUC1-probe of this nanocarrier targeted MUC1 protein of MUC1-positive cells, causing a conformational reorganization of MUC1 aptamer, releasing complementary sequence with quencher and leading to fluorescence recovery. Subsequently, after internalizing into cells, AS1411 aptamer moiety of nanocarrier bound to nucleolin selectively, then the whole nanocarrier targeted nucleus and released Dox into nucleus. MUC1-positive cells and MUC1-negative cells could be differentiated by means of fluorescence imaging. Versus free Dox, Dox-loaded MUC1-Td-AS1411 showed lower cytotoxicity to MUC1-negative HL-7702 cells (P < 0.01), approximately equal lethality to sensitive MCF-7 cells (P > 0.05) whereas more effective to doxorubicin-resistant MCF-7 cells (P < 0.01). Therefore, this nanocarrier could be used as a promising candidate for cancer theranostics.

    更新日期:2017-11-20
  • Calibration transfer of a Raman spectroscopic quantification method for the assessment of liquid detergent compositions from at-line laboratory to in-line industrial scale
    Talanta (IF 4.162) Pub Date : 2017-11-20
    D. Brouckaert, J.-S. Uyttersprot, W. Broeckx, T. De Beer

    Calibration transfer or standardisation aims at creating a uniform spectral response on different spectroscopic instruments or under varying conditions, without requiring a full recalibration for each situation. In the current study, this strategy is applied to construct at-line multivariate calibration models and consequently employ them in-line in a continuous industrial production line, using the same spectrometer. Firstly, quantitative multivariate models are constructed at-line at laboratory scale for predicting the concentration of two main ingredients in hard surface cleaners. By regressing the Raman spectra of a set of small-scale calibration samples against their reference concentration values, partial least squares (PLS) models are developed to quantify the surfactant levels in the liquid detergent compositions under investigation. After evaluating the models performance with a set of independent validation samples, a univariate slope/bias correction is applied in view of transporting these at-line calibration models to an in-line manufacturing set-up. This standardisation technique allows a fast and easy transfer of the PLS regression models, by simply correcting the model predictions on the in-line set-up, without adjusting anything to the original multivariate calibration models. An extensive statistical analysis is performed in order to assess the predictive quality of the transferred regression models. Before and after transfer, the R2 and RMSEP of both models is compared for evaluating if their magnitude is similar. T-tests are then performed to investigate whether the slope and intercept of the transferred regression line are not statistically different from 1 and 0, respectively. Furthermore, it is inspected whether no significant bias can be noted. F-tests are executed as well, for assessing the linearity of the transfer regression line and for investigating the statistical coincidence of the transfer and validation regression line. Finally, a paired t-test is performed to compare the original at-line model to the slope/bias corrected in-line model, using interval hypotheses. It is shown that the calibration models of Surfactant 1 and Surfactant 2 yield satisfactory in-line predictions after slope/bias correction. While Surfactant 1 passes seven out of eight statistical tests, the recommended validation parameters are 100% successful for Surfactant 2. It is hence concluded that the proposed strategy for transferring at-line calibration models to an in-line industrial environment via a univariate slope/bias correction of the predicted values offers a successful standardisation approach.

    更新日期:2017-11-20
  • Raman Spectra of Thiolated Arsenicals with Biological Importance
    Talanta (IF 4.162) Pub Date : 2017-11-17
    Mingwei Yang, Yuzhen Sun, Xiaobin Zhang, Bruce McCord, Anthony J. McGoron, Alexander Mebel, Yong Cai

    Surface enhanced Raman scattering (SERS) has great potential as an alternative tool for arsenic speciation in biological matrices. SERS measurements have advantages over other techniques due to its ability to maintain the integrity of arsenic species and its minimal requirements for sample preparation. Up to now, very few Raman spectra of arsenic compounds have been reported. This is particularly true for thiolated arsenicals, which have recently been found to be widely present in humans. The lack of data for Raman spectra in arsenic speciation hampers the development of new tools using SERS. Herein, we report the results of a study combining the analysis of experimental Raman spectra with that obtained from density functional calculations for some important arsenic metabolites. The results were obtained with a hybrid functional B3LYP approach using different basis sets to calculate Raman spectra of the selected arsenicals. By comparing experimental and calculated spectra of dimethylarsinic acid (DMAV), the basis set 6–311++G⁎⁎ was found to provide computational efficiency and precision in vibrational frequency prediction. The Raman frequencies for the rest of organoarsenicals were studied using this basis set, including monomethylarsonous acid (MMAIII), dimethylarsinous acid (DMAIII), dimethylmonothioarinic acid (DMMTAV), dimethyldithioarsinic acid (DMDTAV), S-(Dimethylarsenic) cysteine (DMAIII(Cys)) and dimethylarsinous glutathione (DMAIIIGS). The results were compared with fingerprint Raman frequencies from As─O, As─C, and As─S obtained under different chemical environments. These fingerprint vibrational frequencies should prove useful in future measurements of different species of arsenic using SERS.

    更新日期:2017-11-20
  • Quantification of amlodipine in dried blood spot samples by high performance liquid chromatography tandem mass spectrometry
    J. Chromatogr. B (IF 2.603) Pub Date : 2017-11-16
    Gaoyun Chen, Feras Jirjees Sr, Abdel Al Bawab, James C. McElnay

    A sensitive and specific method, utilising high performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS) was developed for the quantitative determination of amlodipine in dried blood spot (DBS) samples. Chromatographic separation was achieved using a Waters XBridge C18 column with gradient elution of a mixture of water and acetonitrile containing 0.1% formic acid (v/v). Amlodipine was quantified using a Waters Quattro Premier mass spectrometer coupled with an electro-spray ionization (ESI) source in positive ion mode. The MRM transitions of 408.9 m/z → 238.1 m/z and 408.9 → 294.0 m/z were used to quantify and qualify amlodipine, respectively. The method was validated across the concentration range of 0.5–30 ng/mL by assessing specificity, sensitivity, linearity, precision, accuracy, recovery and matrix effect according to the Food and Drug Administration (FDA) guidelines. This method was also validated clinically within a large pharmacoepidemiological study in which amlodipine blood concentration were determined in patients who had been prescribed this medication.

    更新日期:2017-11-20
  • Determination of non-liposomal and liposomal doxorubicin in plasma by LC–MS/MS coupled with an effective solid phase extraction: In comparison with ultrafiltration technique and application to a pharmacokinetic study
    J. Chromatogr. B (IF 2.603) Pub Date : 2017-11-16
    Yaping Xie, Nan Shao, Yi Jin, Liang Zhang, Huan Jiang, Ningjie Xiong, Fangming Su, Haiyan Xu

    Liposomal formulation of doxorubicin has been widely applied in clinic for treatment of various cancers. The separation and measurement of free drug (drug which is not entrapped in liposomes) and liposomal drug in the plasma after injection of liposomal doxorubicin is of prime importance due to toxicity and activity concerns. In this study, a rapid and convenient method was developed to isolate and determine the non-liposomal and liposomal drugs in plasma. Plasma samples were prepared by solid phase extraction (SPE) using Oasis HLB cartridges. Liposomal doxorubicin (L-DOX) was collected in the aqueous eluate with its internal standard (IS), metformin; and non-liposomal doxorubicin (NL-DOX) and its isotope labelling IS were eluted from the cartridge by methanol containing 0.5% formic acid. After SPE separation, L-DOX and NL-DOX were subsequently quantified by a validated sensitive LC–MS/MS method individually. The calibration curves were found to be linear for L-DOX in the range of 0.156–40.0 μg/mL and for NL-DOX in the range of 3.13–200 ng/mL. The extraction recovery was about 97% for L-DOX and about 65% for NL-DOX. This method was further applied to investigate the pharmacokinetics of doxorubicin in Beagle dogs after an intravenous dose of 1.0 mg/kg Doxil®. After injection of Doxil®, L-DOX was the predominant component circulating in plasma, whose amount was about 1000-fold higher than that of NL-DOX. The analytical method might be helpful in pharmacokinetics and toxicity assessment of liposomal formulation.

    更新日期:2017-11-20
  • Liquid chromatography coupled to tandem mass spectrometry for detecting ten allergens in complex and incurred foodstuffs
    J. Chromatogr. A (IF 3.981) Pub Date : 2017-11-20
    M. Planque, T. Arnould, M. Dieu, P. Delahaut, P. Renard, N. Gillard

    Food allergy is a considerable heath problem, as undesirable contaminations by allergens during food production are still widespread and may be dangerous for human health. To protect the population, laboratories need to develop reliable analytical methods in order to detect allergens in various food products. Currently, a large majority of allergen-related food recalls concern bakery products. It is therefore essential to detect allergens in unprocessed and processed foodstuffs. In this study, we developed a method for detecting ten allergens in complex (chocolate, ice cream) and processed (cookie, sauce) foodstuffs, based on ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS). Using a single protocol and considering a signal-to-noise ratio higher than 10 for the most abundant multiple reaction monitoring (MRM) transition, we were able to detect target allergens at 0.5 mg/kg for milk proteins, 2.5 mg/kg for peanut, hazelnut, pistachio, and cashew proteins, 3 mg/kg for egg proteins, and 5 mg/kg for soy, almond, walnut, and pecan proteins. The ability of the method to detect 10 allergens with a single protocol in complex and incurred food products makes it an attractive alternative to the ELISA method for routine laboratories.

    更新日期:2017-11-20
  • Solvent Front Position Extraction procedure with thin-layer chromatography as a mode of multicomponent sample preparation for quantitative analysis by instrumental technique
    J. Chromatogr. A (IF 3.981) Pub Date : 2017-11-20
    A. Klimek-Turek, E. Sikora, T.H. Dzido

    A concept of using thin-layer chromatography to multicomponent sample preparation for quantitative determination of solutes followed by instrumental technique is presented. Thin-layer chromatography (TLC) is used to separate chosen substances and their internal standard from other components (matrix) and to form a single spot/zone containing them at the solvent front position. The location of the analytes and internal standard in the solvent front zone allows their easy extraction followed by quantitation by HPLC.

    更新日期:2017-11-20
  • Applications of 2, 2, 2 Trifluoroethanol as a Versatile Co-solvent in Supercritical Fluid Chromatography for Purification of Unstable Boronate Esters, Enhancing Throughput, Reducing Epimerization, and for Additive Free Purifications
    J. Chromatogr. A (IF 3.981) Pub Date : 2017-11-20
    Kathiravan Asokan, Khaja Mohinddin Shaikh, Shahaji Sopan Tele, Siddheshwar Kisan Chauthe, Shabana Ansar, Muthalagu Vetrichelvan, Roshan Nimje, Anuradha Gupta, Arun Kumar Gupta, Ramakanth Sarabu, Dauh-Rurng Wu, Arvind Mathur, Lakshmikant Bajpai

    Analysis and purification of boronic acid pinacol esters by RPLC is very challenging due to their degradation in aqueous and alcoholic solvents. These compounds are difficult to purify by SFC too as they are equally sensitive to traditional co-solvents like methanol, ethanol, and 2-propanol. 2,2,2 trifluoroethanol (TFE), which has been reported for the purification of a few alcohol sensitive compounds, was evaluated as a co-solvent in this study for the purification of chiral and achiral boronate esters by SFC. Examples of twelve compounds were presented in this paper where degradation of boronic acid pinacol esters was successfully controlled by replacing methanol with TFE as the co-solvent in SFC. A separate study showed that TFE can also control the epimerization of the enantiomers of 3 substituted 1,4 benzodiazepine analogues during the purification process. In addition to above benefits, 2,2,2trifloroethanol showed improved selectivity and resolution for most of the compounds. With its stronger solvent strength compared to other alcohols, TFE could also be used to reduce the co-solvent percentage needed for elution and to shorten retention time of highly polar samples which did not elute even in 50% of other co-solvents in SFC. A case study of compound B demonstrated that TFE provided a reduced co-solvent percentage and a shorter cycle time with much improved resolution as compared to methanol, thus resulting in higher loading and throughput with reduction of total solvent consumption.

    更新日期:2017-11-20
  • Mechanical characterisation of agarose-based chromatography resins for biopharmaceutical manufacture
    J. Chromatogr. A (IF 3.981) Pub Date : 2017-11-20
    Mauryn C. Nweke, R. Graham McCartney, Daniel G. Bracewell

    Mechanical characterisation of agarose-based resins is an important factor in ensuring robust chromatographic performance in the manufacture of biopharmaceuticals. Pressure-flow profiles are most commonly used to characterise these properties. There are a number of drawbacks with this method, including the potential need for several re-packs to achieve the desired packing quality, the impact of wall effects on experimental set up and the quantities of chromatography media and buffers required. To address these issues, we have developed a dynamic mechanical analysis (DMA) technique that characterises the mechanical properties of resins based on the viscoelasticity of a 1 ml sample of slurry. This technique was conducted on seven resins with varying degrees of mechanical robustness and the results were compared to pressure-flow test results on the same resins. Results show a strong correlation between the two techniques. The most mechanically robust resin (Capto Q) had a critical velocity 3.3 times higher than the weakest (Sepharose CL-4B), whilst the DMA technique showed Capto Q to have a slurry deformation rate 8.3 times lower than Sepharose CL-4B. To ascertain whether polymer structure is indicative of mechanical strength, scanning electron microscopy images were also used to study the structural properties of each resin. Results indicate that DMA can be used as a small volume, complementary technique for the mechanical characterisation of chromatography media.

    更新日期:2017-11-20
  • Chemomics-based marker compounds mining and mimetic processing for exploring chemical mechanisms in traditional processing of herbal medicines, a continuous study on Rehmanniae Radix
    J. Chromatogr. A (IF 3.981) Pub Date : 2017-11-20
    Li Zhou, Jin-Di Xu, Shan-Shan Zhou, Hong Shen, Qian Mao, Ming Kong, Ye-Ting Zou, Ya-Yun Xu, Jun Xu, Song-Lin Li

    Exploring processing chemistry, in particular the chemical transformation mechanisms involved, is a key step to elucidate the scientific basis in traditional processing of herbal medicines. Previously, taking Rehmanniae Radix (RR) as a case study, the holistic chemome (secondary metabolome and glycome) difference between raw and processed RR was revealed by integrating hyphenated chromatographic techniques-based targeted glycomics and untargeted metabolomics. Nevertheless, the complex chemical transformation mechanisms underpinning the holistic chemome variation in RR processing remain to be extensively clarified. As a continuous study, here a novel strategy by combining chemomics-based marker compounds mining and mimetic processing is proposed for further exploring the chemical mechanisms involved in herbal processing. First, the differential marker compounds between raw and processed herbs were rapidly discovered by untargeted chemomics-based mining approach through multivariate statistical analysis of the chemome data obtained by integrated metabolomics and glycomics analysis. Second, the marker compounds were mimetically processed under the simulated physicochemical conditions as in the herb processing, and the final reaction products were chemically characterized by targeted chemomics-based mining approach. Third, the main chemical transformation mechanisms involved were clarified by linking up the original marker compounds and their mimetic processing products. Using this strategy, a set of differential marker compounds including saccharides, glycosides and furfurals in raw and processed RR was rapidly found, and the major chemical mechanisms involved in RR processing were elucidated as stepwise transformations of saccharides (polysaccharides, oligosaccharides and monosaccharides) and glycosides (iridoid glycosides and phenethylalcohol glycosides) into furfurals (glycosylated/non-glycosylated hydroxymethylfurfurals) by deglycosylation and/or dehydration. The research deliverables indicated that the proposed strategy could advance the understanding of RR processing chemistry, and therefore may be considered a promising approach for delving into the scientific basis in traditional processing of herbal medicines.

    更新日期:2017-11-20
  • SERS activated platform with three-dimensional hot spots and tunable nanometer gap
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-20
    Chao Zhangt, Chonghui Li, Jing Yu, Shouzhen Jiang, Shicai Xu, Cheng Yang, Yan Jun Liu, Xingguo Gao, Aihua Liu, Baoyuan Man

    Hot spots have been considered as a dominant role in surface enhancement Raman scattering (SERS). Its generation cannot be separated from the ultra-small nanogaps, which will tremendously contribute to the strong electromagnetic field. We propose a AgNPs/graphene@AuNPs system with three-dimensional hot spots and tunable nanometer gap by changing the layer of graphene with a simple and facile method. The excellent SERS behaviors of the proposed AgNPs/graphene@AuNPs substrate are demonstrated experimentally using rhodamine 6G (R6G) and crystal violet (CV) as probe molecules and theoretically using commercial COMSOL software. The excellent SERS behaviors can be attributed to the electromagnetic mechanism (EM) in all three dimensions introduced by the lateral nanogaps (AgNP-AgNP) and the vertical nanogaps (AgNP-AuNPs), and the chemical enhancement mechanism (CM) induced by the graphene film. For practical application, the prepared sensitive AgNPs/graphene@AuNPs SERS substrate was used to detect Malachite green (MG) in sea water, which provides a bran-new avenue for the detection of biological and chemical molecule.

    更新日期:2017-11-20
  • A Surface Expressed Alkaline phosphatase Biosensor modified with Flower shaped ZnO for the Detection of Chlorpyrifos
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-20
    Manisha Pabbi, Amanpreet Kaur, Susheel K. Mittal, Ritu Jindal

    A simple and rapid Chlorella sp. surface expressed alkaline phosphatase (AP-algae) biosensor modified with flower shaped ZnO nanoparticles for the determination of chlorpyrifos in an aqueous medium was developed. The detection principle was based on the inhibition of AP-algae in presence of chlorpyrifos. Enzyme would dephosphorylate the phosphate monoester of substrate 2-phospho-l-ascorbic acid to release l-ascorbic acid, which was monitored using voltammetric and ISFET techniques. The presence of pesticide would inhibit AP-algae enzyme activity and hence the current magnitude decreases. The decrease in current is quantitative in nature and used for determination of concentration of the pesticide. Flower shape ZnO nanoparticles not only provide surface for adsorption of AP-algae for better immobilization but also increases electron-transfer kinetics and sensitivity of the biosensor. The voltammetric and ISFET methods could measure chlorpyrifos in the linear concentration range from 10−9 M to 10−1 M and 10−10 M to 10−3 M, respectively, with nil interference from triazophos, malathion, acephate and some metal ions. Application aspects of the proposed biosensor were demonstrated using extracted soil samples and showed excellent reproducibility and reliability.

    更新日期:2017-11-20
  • High-Performance Porous MIM-Type Capacitive Humidity Sensor Realized via Inductive Coupled Plasma and Reactive-Ion Etching
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-20
    Tian Qiang, Ming-Qing Liu, Kishor Kumar Adhikari, Jun-Ge Liang, Lei Wang, Yang Li, Yu-Ming Wu, Guo-Hui Yang, Fan-Yi Meng, Jia-Hui Fu, Qun Wu, Nam-Young Kim, Zhao Yao, Cong Wang

    We propose a high-performance porous metal–insulator–metal-type capacitive humidity sensor based on a functional polymer mixed with TiO2 microparticles subjected to inductively coupled plasma (ICP) and reactive-ion etching (RIE) treatments. The humidity sensor is composed of a porous top electrode, a TiO2-containing functional polymer humidity-sensitive layer subjected to two types of oxygen plasma treatment, a bottom electrode, and a glass substrate. The initial O2 ICP dry-etching utilizes higher intensity plasma for deep etching in the inlet holes on the top electrode to increase the contact area and shorten the vapor absorption path, thereby yielding high sensitivity and low hysteresis. Further, the RIE treatment leads to roughening of the polymer etching surface and further improving the performance of the humidity sensor. The functional polymer mixed with TiO2 microparticles exhibits excellent hysteresis over a wide humidity sensing range. The fabricated sensors are tested at various relative humidity (RH) values, achieving an ultra-low hysteresis of 0.64% RH at 60% RH, a high sensitivity of 1.24 pF/% RH, a fast response time of less than 25 s, good temperature dependence, and a stable capacitance value with a maximum error rate of 0.15% over 120 h of continuous testing.

    更新日期:2017-11-20
  • Fungus-derived photoluminescent carbon nanodots for ultrasensitive detection of Hg2+ ions and photoinduced bactericidal activity
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-20
    Sada Venkateswarlu, Buddolla Viswanath, Ankireddy Seshadri Reddy, Minyoung Yoon

    Herein, we present a sustainable solvent-free synthetic procedure to produce carbon nanodots from common edible mushrooms (Pleurotus spp.). The resulting mushroom carbon nanodots (MCDs) exhibit stable blue fluorescence with high quantum yield (25%). The MCDs are highly dispersible in water because of the enormous number of oxygen- and nitrogen-containing functional groups on the surface. The MCDs can be used as an effective fluorescent probe for label-free detection of Hg2+ ions (detection limit: 4.13 nM). To improve the sensitivity, dihydrolipoicacid acid was attached to the surface of MCDs, resulting in ultra-sensitivity in Hg2+ ion sensing, with a detection limit as low as 17.4 pM. In addition, the MCDs can be used for the labeling of bacteria and as a photoinduced bactericidal agent. Light irradiation of E. coli treated with MCDs showed excellent bactericidal activity relative to the control. These sustainable and affordable carbon materials are potentially compatible for monitoring toxic metals and as a potent visible-light-responsive bactericidal probe.

    更新日期:2017-11-20
  • High-sensitive Electrochemical Sensor for Determination of Norfloxacin and Its Metabolism Using MWCNT-CPE/pRGO-ANSA/Au
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-17
    Zhenping Liu, Mingliang Jin, Jieping Cao, Juan Wang, Xin Wang, Guofu Zhou, Albert van den Berg, Lingling Shui

    In this work, a high-sensitive electrochemical sensor of Norfloxacin (NFX) has been developed using a composite electrode of MWCNT-CPE/pRGO-ANSA/Au. MWCNT-CPE is the multi-walled carbon nanotubes (MWCNT) – carbon paste electrode (CPE). pRGO-ANSA means the partially reduced graphene oxide (pRGO) – 6-aminonaphthalene-2-sulphonic acid (ANSA) hybrid nanomaterials. Au represents gold nanoparticles. The electrochemical sensing of NFX was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV). Experimental results show that the combination of MWCNT-CPE/pRGO-ANSA/Au offers high electrical conductivity, large surface area and excellent electrocatalytic activity, being beneficial for electrochemical sensing performance. The calibration curves of NFX exhibit linear response in the NFX concentration range of 0.03-1.0 and 1.0-50.0 μM, with the limit of detection (LOD) of 0.016 μM (S/N = 3). The fabricated sensors were successfully applied for detecting the presence of NFX in pharmaceutical formulations and rat plasma samples. The measured results were comparable with those obtained using ultrahigh performance liquid chromatography (UHPLC), indicating its high potential for applications in pharmaceutical analysis and clinical therapeutic drug monitoring.

    更新日期:2017-11-20
  • 2-(4-Amino-2-hydroxyphenyl)benzothiazole based Schiff-base: Complexation/decomplexation driven photo physical tuning of fluorescence leading to Cu2+ and PO43− detection
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-17
    Ishpreet Kaur, Paramjit Kaur, Kamaljit Singh

    We report a 2-(4-amino-2-hydroxyphenyl)benzothiazole based Schiff-base, a potential excited state intramolecular proton transfer (ESIPT) chromophore, exhibits aggregation induced emission enhancement (AIEE) in the solvent mixture of DMSO:HB. The presence of Cu2+ ions promote imine hydrolysis resulting the formation of Cu2+ complex of 2-(4-amino-2-hydroxyphenyl)benzothiazole, with the consequent cessation of the emission process leading to “turn-off” detection of Cu2+. The introduction of PO43− ions revived fluorescence emission through decomplexation of the putative Cu2+ complex, thereby releasing 2-(4-amino-2-hydroxyphenyl)benzothiazole in the solution. Additionally, we have successfully demonstrated the practical application of the probe by developing the portable sensor paper strips.

    更新日期:2017-11-20
  • Direct and Sensitive Determination of Trypsin in Human Urine Using a Water-Soluble Signaling Fluorescent Molecularly Imprinted Polymer Nanoprobe
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-16
    Jingjing Xu, Elise Prost, Karsten Haupt, Bernadette Tse Sum Bui

    A molecularly imprinted polymer (MIP) for biosensing trypsin is prepared by incorporating a benzamidine-based signaling fluorescent monomer during its synthesis. Binding to trypsin results in a 100-fold fluorescence enhancement when the MIP is excited with UV light. The assay can be performed by simply mixing a small amount of water-soluble MIP (100 μg) and trypsin together in a quartz cuvette, followed by a direct read-out on a spectrofluorimeter. There is no need to separate the free from the bound trypsin. The limit of quantification is 50 nM in phosphate buffer and 210 nM in urine. The aqueous MIP is prepared by a solid-phase synthesis method on glass-beads functionalized with a metal chelate to immobilize trypsin via its surface histidine. The active site of the enzyme is left free for binding to the benzamidine moiety of the fluorescent monomer, resulting in a sensitive MIP for probing the enzyme’s active site. Incorporation of a thermoresponsive monomer, N-isopropyacrylamide, in the polymerization mixture, yields thermoresponsive MIP nanoparticles that are released from the support by a simple temperature change, generating template-free polymers. The MIPs are endowed with improved binding site homogeneity since all binding sites have the same orientation. Their size is ∼70 nm and the dissociation constant (Kd) of the MIP-trypsin complex is 237 nM, with little or no cross-reactivity with other proteins, including serine proteases.

    更新日期:2017-11-20
  • Novel urchin-like Co9S8 nanomaterials with efficient intrinsic peroxidase-like activity for colorimetric sensing of copper (II) ion
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-16
    Jianshuai Mu, Jie Li, Xin Zhao, En-Cui Yang, Xiao-Jun Zhao

    Novel and uniform urchin-like Co9S8 nanomaterials assembled with needle-like nanorods were synthesized by a facile two-step hydrothermal process, and were found to intrinsic peroxidase-like activity. As a new peroxidase mimic, their catalytic properties, kinetics and mechanism were studied in depth by several techniques. The results showed that the catalytic activity of urchin-like Co9S8 nanomaterials was highly efficient, which was arised from high electron-transfer ability of their unique morphology. Interestingly, using the peroxidase-like activity of urchin-like Co9S8 nanomaterials, a novel off-on sensor for detection of Cu2+ was constructed. The sensor showed a good linear range of 0.5–10 μM with a low detection limit of 0.09 μM. The proposed method was successfully applied for Cu2+ determination in real samples with satisfactory results.

    更新日期:2017-11-20
  • Determining the Liquid Light Scattering Cross Section and Depolarization Spectra Using Polarized Resonance Synchronous Spectroscopy
    Anal. Chem. (IF 6.32) Pub Date : 2017-11-20
    Sumudu A. Athukorale, Yadong Zhou, Shengli Zou, Dongmao Zhang
    更新日期:2017-11-20
  • Indirect Nanoplasmonic Sensing Platform for Monitoring Temperature-Dependent Protein Adsorption
    Anal. Chem. (IF 6.32) Pub Date : 2017-11-20
    Joshua A. Jackman, Abdul Rahim Ferhan, Bo Kyeong Yoon, Jae Hyeon Park, Vladimir P. Zhdanov, Nam-Joon Cho
    更新日期:2017-11-20
  • Electrochemical impedance spectroscopy of blood. Part 3: A study of the correlation between blood conductivity and sedimentation to shorten the erythrocyte sedimentation rate test
    Anal. Methods (IF 1.9) Pub Date : 2017-11-20
    Alexander Zhbanov, Sung Yang

    The study of erythrocyte aggregation and erythrocyte sedimentation rate (ESR) is very important both for basic research and medical applications. The duration of the Westergren ESR test is one hour which seems excessive. The hematocrit and conductivity of blood demonstrate high correlation. This makes it possible to evaluate the erythrocyte aggregation kinetics and ESR by measuring changes in the blood conductivity. We measured the time-dependent changes in conductivity at the bottom of the blood column during sedimentation. A digital camera is used to obtain the blood sedimentation curve and to determine the hematocrit profile. The effective conductivity of blood is calculated based on the effective medium theory. Simple analytical expressions are derived to extrapolate changes in blood conductivity over time. We proposed an improved physical model of sedimentation which reveals additional information about the kinetics of blood sedimentation and erythrocyte aggregation. An explicit expression is obtained to characterize the rate of aggregate formation. A numerical model was developed to investigate these mechanisms, and it was tested by comparing simulation results with experimental data. Based on our model, the ESR, blood sedimentation curve and hematocrit profiles can be numerically restored using only the first 400 seconds of the recorded changes in blood conductivity. The proposed technique allows measuring the erythrocyte aggregation as well as the sedimentation kinetics. The changes in blood conductivity on the bottom of the blood column at the initial stage of sedimentation reliably reflect the erythrocyte aggregation kinetics and ESR over time.

    更新日期:2017-11-20
  • TiO2/CdS nanorod array based photoelectrochemical sensing of Cu2+ in human serum samples
    Anal. Methods (IF 1.9) Pub Date : 2017-11-20
    Kejun Feng, Minghui Yang, Fang Xie, Guiqiang Diao, Mingming Ou, Huanfeng Huang

    In this work, we report a sensitive and selective photoelectrochemical sensor for detection of Cu2+ in human serum samples based on TiO2/CdS nanorod array. To prepare the sensor, TiO2 nanorod array was initially deposited onto fluorine-doped tin oxide (FTO) conductive glass, and then CdS nanoparticles were deposited onto the TiO2 nanorod array surface. The well-matched energy level between TiO2 nanorod and CdS efficiently suppressed the recombination of photogenerated electron and hole (e−/h+) pairs, leading to improved photon-to-current conversion efficiency. Experimental results demonstrated increased photoelectrochemical current of TiO2/CdS compared to TiO2 along. Utilizing the interaction between Cu2+ and CdS, the constructed photoelectrochemical sensing platform shows selective response towards Cu2+. Increased Cu2+ concentration resulted in the decreased photoelectrochemical current intensity and a linear range of 1nM-1M was obtained with a detection limit of 0.5 nM. Regarding the good performances, the sensor was successfully applied for direct detection of Cu2+ in human serum samples, which suggests the potential practical clinical applications.

    更新日期:2017-11-20
  • Ag@SiO2 Nanocubes Loaded Miniaturized Filter Paper as Hybrid Flexible Plasmonic SERS Substrate for Trace Melamine Detection
    Anal. Methods (IF 1.9) Pub Date : 2017-11-20
    Menbere Leul Mekonnen, Wei-Nien Su, Ching-Hsiang Chen, Bing Joe Hwang

    A robust flexible paper-plasmonic hybrid SERS substrate is reported by exploiting the intrinsic properties of filter paper and anisotropic Ag@SiO2 nanocubes. The fibrous structure of paper promotes the assemblage of sharp-edged nanostructures which significantly improved the SERS activity. Inexpensive sensing platform with reasonable distribution and interparticle spacing of nanocubes was obtained by filtering Ag@SiO2 through a miniaturized filter paper. The thin silica shell improved the stability and interparticle spacing of silver nanocubes in the sensing platform, rendering enhanced SERS activity through plasmon-coupling effect as compared to a conventional rigid substrate. Assessment of analytical performances of the substrate for melamine quantification showed a good linearity (R2 = 0.9948) up to 1 mg/L with a limit of detection 0.06 mg/L. The detection limit in liquid milk was down to 0.17 mg/L, which is below the permissible residue limit signifying adequate sensitivity for real sample analysis with less sample treatment.

    更新日期:2017-11-20
  • Mask-free fabrication of a versatile microwell chip for multidimensional cellular analysis and drug screening
    Lab Chip (IF 6.045) Pub Date : 2017-11-09
    Wenguang Yang, Haibo Yu, Gongxin Li, Fanan Wei, Yuechao Wang, Lianqing Liu
    更新日期:2017-11-20
  • Photoionization of environmentally polluting aromatic chlorides and nitrides on the water surface by laser and synchrotron radiations
    Analyst (IF 3.885) Pub Date : 2017-11-08
    Miki Sato, Yuki Maeda, Toshio Ishioka, Akira Harata
    更新日期:2017-11-20
  • A lysosome-locating and acidic pH-activatable fluorescent probe for visualizing endogenous H2O2 in lysosomes
    Analyst (IF 3.885) Pub Date : 2017-11-03
    Jun Liu, Shunqing Zhou, Jing Ren, Chuanliu Wu, Yibing Zhao
    更新日期:2017-11-20
  • Acceleration of metal–ligand complexation kinetics by electrospray ionization
    Analyst (IF 3.885) Pub Date : 2017-11-02
    Morgan P. Kelley, Austen Davis, Brian Clowers, Aurora E. Clark, Sue B. Clark
    更新日期:2017-11-20
  • Electrochemical reactive oxygen species detection by cytochrome c immobilized with vertically aligned and electrochemically reduced graphene oxide on a glassy carbon electrode
    Analyst (IF 3.885) Pub Date : 2017-10-31
    Dinakaran Thirumalai, Vijayaraj Kathiresan, Jaewon Lee, Sung-Ho Jin, Seung-Cheol Chang
    更新日期:2017-11-20
  • Micro/nanoelectrochemical probe and chip devices for evaluation of three-dimensional cultured cells
    Analyst (IF 3.885) Pub Date : 2017-10-26
    Kosuke Ino, Mustafa Şen, Hitoshi Shiku, Tomokazu Matsue
    更新日期:2017-11-20
  • Improved identification and quantitation of mature endogenous peptides in the rodent hypothalamus using a rapid conductive sample heating system
    Analyst (IF 3.885) Pub Date : 2017-10-26
    Ning Yang, Krishna D. B. Anapindi, Elena V. Romanova, Stanislav S. Rubakhin, Jonathan V. Sweedler
    更新日期:2017-11-20
  • Chemical modification of antibodies enables the formation of stable antibody–gold nanoparticle conjugates for biosensing
    Analyst (IF 3.885) Pub Date : 2017-10-26
    Seth L. Filbrun, Alexandra B. Filbrun, Francis L. Lovato, Soon H. Oh, Elizabeth A. Driskell, Jeremy D. Driskell
    更新日期:2017-11-20
  • A new tetraphenylethylene based AIE sensor with light-up and tunable measuring range for adenosine triphosphate in aqueous solution and in living cells
    Analyst (IF 3.885) Pub Date : 2017-10-26
    Guoyu Jiang, Wenping Zhu, Qingqing Chen, Aiping Shi, Yongquan Wu, Guanxin Zhang, Xun Li, Yongdong Li, Xiaolin Fan, Jianguo Wang
    更新日期:2017-11-20
  • ProxyPhos sensors for the detection of negatively charged membranes
    Analyst (IF 3.885) Pub Date : 2017-10-24
    Bronte I. Murcar-Evans, Aaron D. Cabral, Krimo Toutah, Elvin D. de Araujo, Angel Lai, Peter M. Macdonald, Angelika Berger-Becvar, Dziyana Kraskouskaya, Patrick T. Gunning
    更新日期:2017-11-20
  • Dynamic sandwich-type electrochemical assay for protein quantification and protein–protein interaction
    Analyst (IF 3.885) Pub Date : 2017-10-20
    Chao Li, Yaqin Tao, Yi Yang, Chang Feng, Yang Xiang, Genxi Li
    更新日期:2017-11-20
  • Tip-enhanced Raman spectroscopy of amyloid β at neuronal spines
    Analyst (IF 3.885) Pub Date : 2017-10-20
    Mohammadali Tabatabaei, Fabiana A. Caetano, Farshid Pashee, Stephen S. G. Ferguson, François Lagugné-Labarthet
    更新日期:2017-11-20
  • Structure-dependent SERS activity of plasmonic nanorattles with built-in electromagnetic hotspots
    Analyst (IF 3.885) Pub Date : 2017-10-20
    Keng-Ku Liu, Sirimuvva Tadepalli, Zheyu Wang, Qisheng Jiang, Srikanth Singamaneni
    更新日期:2017-11-20
  • Recent advances in phosphoproteomics and application to neurological diseases
    Analyst (IF 3.885) Pub Date : 2017-10-20
    Justine V. Arrington, Chuan-Chih Hsu, Sarah G. Elder, W. Andy Tao
    更新日期:2017-11-20
  • Stable isotope labeling by essential nutrients in cell culture (SILEC) for accurate measurement of nicotinamide adenine dinucleotide metabolism
    Analyst (IF 3.885) Pub Date : 2017-10-18
    David W. Frederick, Sophie Trefely, Alexia Buas, Jason Goodspeed, Jay Singh, Clementina Mesaros, Joseph A. Baur, Nathaniel W. Snyder
    更新日期:2017-11-20
  • Quantification of a bacterial secondary metabolite by SERS combined with SLM extraction for bioprocess monitoring
    Analyst (IF 3.885) Pub Date : 2017-10-17
    Lidia Morelli, Sune Zoëga Andreasen, Christian Bille Jendresen, Alex Toftgaard Nielsen, Jenny Emnéus, Kinga Zór, Anja Boisen
    更新日期:2017-11-20
  • Plasmonic nanocone arrays for rapid and detailed cell lysate surface enhanced Raman spectroscopy analysis
    Analyst (IF 3.885) Pub Date : 2017-10-17
    L. P. Hackett, L. L. Goddard, G. L. Liu
    更新日期:2017-11-20
  • Magnetic sulfur-doped porous carbon for preconcentration of trace mercury in environmental water prior to ICP-MS detection
    Analyst (IF 3.885) Pub Date : 2017-10-17
    Chuyu Peng, Man He, Beibei Chen, Lijin Huang, Bin Hu
    更新日期:2017-11-20
  • Synthesis of highly fluorescent gold nanoclusters and their use in sensitive analysis of metal ions
    Analyst (IF 3.885) Pub Date : 2017-10-17
    Yayu Yang, Ailing Han, Ruixue Li, Guozhen Fang, Jifeng Liu, Shuo Wang
    更新日期:2017-11-20
  • OCT imaging detection of brain blood vessels in mouse, based on semiconducting polymer nanoparticles
    Analyst (IF 3.885) Pub Date : 2017-10-17
    Shaozhuang Yang, Haobin Chen, Liwei Liu, Bingling Chen, Zhigang Yang, Changfeng Wu, Siyi Hu, Huiyun Lin, Buhong Li, Junle Qu
    更新日期:2017-11-20
  • 更新日期:2017-11-20
  • Multiplexed detection of microRNAs by a competitive DNA microarray-based resonance light scattering assay
    Analyst (IF 3.885) Pub Date : 2017-10-12
    Xia Liu, Rongrong Tian, Jiaxue Gao, Dianjun Liu, Zhenxin Wang
    更新日期:2017-11-20
  • 更新日期:2017-11-20
  • A new lateral-flow immunochromatographic strip combined with quantum dot nanobeads and gold nanoflowers for rapid detection of tetrodotoxin
    Analyst (IF 3.885) Pub Date : 2017-10-11
    Haicong Shen, Fei Xu, Meng Xiao, Qiangqiang Fu, Zhenzhu Cheng, Shiwei Zhang, Caihong Huang, Yong Tang
    更新日期:2017-11-20
  • Direct comparison of derivatization strategies for LC-MS/MS analysis of N-glycans
    Analyst (IF 3.885) Pub Date : 2017-10-10
    Shiyue Zhou, Lucas Veillon, Xue Dong, Yifan Huang, Yehia Mechref
    更新日期:2017-11-20
  • Raman and infrared spectroscopy differentiate senescent from proliferating cells in a human dermal fibroblast 3D skin model
    Analyst (IF 3.885) Pub Date : 2017-08-07
    Katharina Eberhardt, Christian Matthäus, Doreen Winter, Cornelia Wiegand, Uta-Christina Hipler, Stephan Diekmann, Jürgen Popp
    更新日期:2017-11-20
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
所有期刊列表A-Z