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  • Electrochemical aptasensor based on a novel flower-like TiO2 nanocomposite for the detection of tetracycline
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Yunfei Tang, Peipei Liu, Jun Xu, LeLe Li, Liwei Yang, Xiaoqiang Liu, Shanhu Liu, Yanmei Zhou

    Herein, we developed a sensitive sensing platform for tetracycline detection by combining the specific DNA aptamers with a novel TiO2 nanocomposite. In this composite, cylinder-shaped TiO2 nanorods were synthesized on MoS2 nanospheres by a facile hydrothermal method to produce a MoS2-TiO2 composite, which was then aminated. Following that, gold nanoparticles (Au) were deposited on the aminated MoS2-TiO2 to form MoS2-TiO2@Au composite, on which thiolated DNA aptamers were applied to construct an electrochemical aptasensor. The tetracycline aptamer could well hybridize to its complementary biotin-DNA oligonucleotide (bio-cDNA), and then avidin-horseradish peroxidase (avidin-HRP) mediated by H2O2 was introduced to produce amplified electrochemical response. The competition between tetracycline and bio-cDNA for binding of the aptamer would decrease the electrochemical signal, which was used for quantitative detection of tetracycline. The prepared aptasensor showed a wide linear range from 1.5 × 10−10 to 6.0 × 10−6 M, and a low detection limit of 5 × 10−11 M.

    更新日期:2017-11-21
  • Ultrasensitive detection of thrombin based on MoS2-aptamer biosensors by resonance light scattering technique
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Yi Liu, Huan Wang, Shiyu Li, Hang Gong, Chunyan Chen, Xiaoming Chen, Changqun Cai

    Rapid and sensitive detection of thrombin has very important significance in biomedical and bioanalytical applications. In this study, a label-free and simple resonance light scattering (RLS) sensor based on MoS2 nanomaterial is developed for ultrasensitive and highly selective detection of thrombin. In the presence of thrombin, the thrombin aptamer can transform into a G-quartet structure and combine with thrombin, resulting in dissociation of the random DNA (rDNA) in the solution. Once MoS2 is introduced, the free rDNA can be adsorbed on the surface of MoS2 to form a stable DNA1–thrombin–MoS2 complex, which increases RLS signals. The sensor shows two linear ranges of 10 pM to 500 pM and 1 nM to 60 nM, and a detection limit of 0.71 pM for detection of thrombin. Our sensor is a promising tool for clinical diagnosis of thrombin in human serum. Moreover, this work can offer new opportunities for the development of convenient sensor for detecting other proteins.

    更新日期:2017-11-21
  • Grinding Lysis (GL): a microfluidic device for sample enrichment and mechanical lysis in one
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Mélanie Flaender, Remco den Dulk, Valentin Flegeau, Jérome Ventosa, Guillaume Delapierre, Jean Berthier, Anne-Gaëlle Bourdat

    Rapid identification of health threatening bacteria and/or spores present in small concentration in sample fluids is of utmost importance. Efficient sample preparation and molecular detection aims to achieving this goal. Two processes must be conducted successively: the concentration of the targets in a small volume with simultaneous purification, followed by their lysis to provide accessible DNA templates. Conventional PCR is then used in situ to identify the targets. In this work we present an original approach combining an efficient concentration and purification of the bacteria and spores, a rapid and efficient grinding lysis step, working even for polluted samples, and the integration of the process in a semi-automated device. The method is very efficient and rapid: it can concentrate and detect less than 10 targets in 1 mL of sample, even if the sample is contaminated by some environmental contaminants. The most resistant spores are successfully lysed. In this study, we successively present the principle and performances of the method, and its integration on a in a semi-automated device. Perspectives to fully integrated system are discussed.

    更新日期:2017-11-21
  • Effective Biosensor Based on Graphene Quantum Dots via Enzymatic Reaction for Directly Photoluminescence Detection of Organophosphate Pesticide
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Chonticha Sahub, Thawatcha Tuntulani, Thumnoon Nhujak, Boosayarat Tomapatanaget

    In this study, the pesticide sensor by graphene quantum dots (GQDs) and active enzyme, GQDs/enzyme platform, has been developed for monitoring the organophosphate pesticides. In this concept, H2O2 generated from the active enzymatic reaction of acetylcholinesterase (AChE) and choline oxidase (CHOx) enables to react with GQDs resulting in a “turn-off” photoluminescence of GQDs. A “turn-on” photoluminescence of GQDs at 467 nm was recovered in the presence of organophosphate. Definitely, the photoluminescence changes of GQDs/AChE/CHOx biosensor reasonably correspond to the amount of pesticide. The detection limit of GQDs/AChE/CHOx biosensor towards dichlorvos was 0.172 ppm (0.778 μM). In this approach, this biosensor offers the promising determination of the organophosphate pesticides and a benefit for easy checking of organophosphate pesticides in food, water and environment with low cost, easy-to-prepare and less toxic to environment.

    更新日期:2017-11-21
  • Polypyrrole shell (nanoparticles)-functionalized silicon nanowires array with enhanced NH3-sensing response
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Yuxiang Qin, Zhen Cui, Tianyi Zhang, Diao Liu

    Conducting polymer of polypyrrole (PPy) was employed to functionalize the ordered silicon nanowire (SiNWs) with the aim to enhance gas-sensing response at room temperature (RT). A dual-MACE process was first developed to form loose SiNWs (LNWs) array facilitating uniform attachment of PPy on whole nanowire surface. The LNWs array functionalized with continuous PPy ultrathin film and discrete PPy nanoparticles, i.e., PPy-shell@LNWs and PPy-NPs@LNWs, were prepared respectively via vapor chemical polymerization (VCP) and liquid chemical polymerization (LCP) of pyrrole monomer (Py). Comparative investigations on the NH3-sensing properties of the pristine SiNWs before and after dual-MACE treatment, and PPy-functionalized SiNWs of PPy-shell@LNWs and PPy-NPs@LNWs were carried out at RT. It was found that PPy functionalization enhances the NH3-sensing response of SiNWs-based sensors effectively. Formation of continuous PPy shell film is further found to result in more pronounced response enhancement when compared to the modification by discrete PPy NPs. The PPy-shell@LNWs and PPy-NPs@LNWs respectively exhibit about 27 and 6 times response enhancement to 10 ppm NH3 gas compared to the pristine one. The underlying NH3-sensing mechanism for the PPy-functionalized SiNWs, especially for the remarkable response enhancement of PPy-shell@SiNWs was demonstrated.

    更新日期:2017-11-21
  • A novel immunoprobe composed of reduced graphene oxide-hemin-thionin-Au nanohybrid for ultrasensitive detection of tumor marker
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Dongsheng Zhang, Weixiang Li, Huiqiang Wang, Zhanfang Ma

    An ultrasensitive electrochemical immunosensor was fabricated by employing reduced graphene oxide-thionin-hemin-Au (H-rGO-Thi-Au) nanohybrid as probe to measure neuron specific enolase (NSE), a lung cancer biomarker. In this work, the reduced graphene oxide (rGO) was used as support material to immobilize hemin and thionin through aromatic π-π interaction. Then Au nanoparticles were reduced by thionin in situ on the probe. The immunoprobe offers several advantages as follows: (1) thionin can be enriched for signal amplification; (2) the catalysis ability of hemin can be enhanced by preventing the molecules aggregation; (3) the reduced graphene oxide-hemin (H-rGO) acts as signal amplifier to accelerate the redox cycling with H2O2; (4) the composite with good conductivity is beneficial to improve response current. Apart from that, polyaniline hydrogel as substrate prepared by electrochemical polymerization on the glassy carbon electrode showed excellent conductivity which can further improve the performance of immunosensor. Thus, the proposed immunosensor showed excellent analytical performance for the detection of NSE with wide linear range from 0.1 pg mL−1 to 100 ng mL−1 and low detection limit of 0.026 pg mL−1. It is also of note that human serum samples were determined with satisfactory results, indicating its value on clinical application.

    更新日期:2017-11-21
  • Rational development of a highly selective ratiometric fluorescent probe for hydrogen polysulfides
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Wenqiang Chen, Xiuxiu Yue, Jiarong Sheng, Wenxiu Li, Liangliang Zhang, Wei Su, Chusheng Huang, Xiangzhi Song

    A novel ratiometric fluorescent probe, ACC-Cl, was developed by virtue of a unique H2Sn-mediated coumarindithiolone formation under mild condition. The probe ACC-Cl exhibited excellent sensitivity and selectivity toward H2Sn over other RSS such as biothiols and H2S. More importantly, titration of H2Sn to the solution of ACC-Cl under the existence of 1 mM GSH, the obvious ratiometric fluorescence response still can be observed. Significantly, preliminary biological experiments indicated its potential for sensing H2Sn in living cells.

    更新日期:2017-11-21
  • Sensitive optical detection of clinically relevant biomarkers in affordable microfluidic devices: overcoming substrate diffusion limitations
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Ana I. Barbosa, Ana P. Castanheira, Nuno M. Reis

    One of the biggest challenges in miniaturization of optical immunoassays is the short light path distance of microchannels/microcapillaries. Protein biomarkers are often presented in circulating blood in the picomolar-femtomolar range, requiring exceptional levels of sensitivity that cannot be met with traditional chromogenic substrates and without sophisticated, bulky detection systems. This study discloses an effective strategy for increasing the sensitivity and shorten the total test time for sandwich ELISAs in microfluidic devices optically interrogated, based on enhancing enzymatic amplification. We found that activity of Horseradish Peroxidase (HRP) in mesofluidic systems is highly limited by diffusion, therefore increasing the concentration of enzymatic substrate in these systems does not translate into an enhancement in enzymatic conversation. The opposite happens in microfluidic systems due to short diffusion distances, however increased concentration of the second enzymatic substrate, hydrogen peroxide (H2O2), leads to enzyme inhibition as herein reported. Consequently, we found that the molar ratio of o-phenylenediamine (OPD) to hydrogen peroxide from commercially substrate formulations is not suitable for miniaturized system. Sandwich ELISA quantitation of a cancer biomarker PSA and human cytokine IL-1β in fluoropolymer microfluidic strips revealed over one order of magnitude increase in sensitivity and 10-fold decrease in incubation time by simply changing the molar ratio of OPD:H2O2 from 1:3 to 1:1 and increasing OPD concentration from 1 to 4 mg/ml. This enhancement in enzymatic amplification offers finally the sensitivity required for optical interrogation of novel portable and affordable microfluidic devices with inexpensive and ubiquitous smartphones and flatbed scanners.

    更新日期:2017-11-21
  • MOFs-derived dodecahedra porous Co3O4: An efficient cataluminescence sensing material for H2S
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Xiaoqun Dong, Yingying Su, Ting Lu, Zhang Lichun, Liqian Wu, Lv Yi

    In the present work, porous Co3O4 was easily prepared via thermal decomposition of metal-organic frameworks (MOFs). TG, FT-IR, XRD, SEM, TEM and N2 adsorption-desorption were employed for characterizing the synthesized products. Based on cataluminescence (CTL) transduction principle, three MOFs including dodecahedra ZIF-67, nanosheets packed Co-MOF-71, nanoplate Co-BTC, and their corresponding derivatives Co3O4 were used as sensing materials for H2S detection, respectively. The dodecahedra ZIF-67-derived dodecahedra Co3O4 with high specific surface and exposed {110} lattice planes presented superior strong CTL property, and had a good linear relation in the concentration range of 3.3 to 27.5 μg L−1 with the detection limit of 1 μg L−1 (S/N = 3), while the original MOFs no CTL signal was observed. Eighteen common volatile organic compounds (VOCs) were investigated as possible interference, and the results indicated that MOFs-derived porous dodecahedra Co3O4 would be one of excellent sensing material candidates for monitoring H2S with a promising application in routine analysis.

    更新日期:2017-11-21
  • An optical biosensor using immunomagnetic separation, urease catalysis and pH indication for rapid and sensitive detection of Listeria monocytogenes
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Qi Chen, Fengchun Huang, Gaozhe Cai, Maohua Wang, Jianhan Lin

    Early screening of pathogenic bacteria in foods plays an important role in foodborne disease prevention and control. In this study, we developed an optical biosensor for rapid and sensitive detection of Listeria monocytogenes combining immunomagnetic separation, urease catalysis and pH indication. The magnetic nanobeads (MNBs) conjugated with monoclonal antibodies (MAbs) by streptavidin-biotin binding were used for specifically and efficiently separating the Listeria cells from background to form magnetically labeled bacteria. Then, the gold nanoparticles (AuNPs) modified with urease and polyclonal antibodies (PAbs) by electrostatic adsorption were used to react with the magnetically labeled bacteria to form the MNB-MAb-Listeria-PAb-AuNP-urease complexes. The urease in the complexes could catalyze the hydrolysis of the urea into ammonium carbonate, which could lead to an increase in the pH value of the urea. Bromcresol purple was compared with phenol red and bromothymol blue and selected as the best pH indicator to monitor the color change, which could be measured at the characteristic wavelength of 588 nm for bacteria quantification. This proposed biosensor was able to detect Listeria monocytogenes as low as 1.0 × 102 CFU/mL, and had the mean recovery of 95.1% for Listeria in the spiked lettuce samples. This optical biosensor has showed its potential to provide a simple, low-cost and sensitive detection method for prevention and control of foodborne diseases.

    更新日期:2017-11-21
  • Two-stage ratiometric fluorescent responsive probe for rapid glutathione detection based on BODIPY thiol-halogen nucleophilic mono- or disubstitution
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Deyan Gong, Jiaxi Ru, Ting Cao, Jing Qian, Wei Liu, Anam Iqbal, Weisheng Liu, Wenwu Qin, Huichen Guo

    3,5-dichloro-8-phenyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BOD-2Cl) (1) as a classical fluorescent dye was synthesized for the purpose of functionalization of BODIPY dye. Herein, it was applied for the purpose of achieving two-stage ratiometric fluorescent detection of glutathione based on the two-step thiol-halogen substitution reaction with the sulfhydryl group of glutathione at the 3 (mono-substitution) and 3,5-position (disubstitution) of 1 in CTAB micelles. The first stage induced fluorescent color change from green (λem = 530 nm) to yellow (λem = 562 nm) (I562nm/I530nm, mono-substitution), excess addition of glutathione caused the second stage fluorescent color change from yellow to red (λem = 597 nm) (I597nm/I562nm, disubstitution). It exhibits excellent properties with specific colorimetric and ratiometric fluorescent change to glutathione over cysteine and homocysteine. Further application to cellular ratiometric fluorescence imaging indicated that the probe was highly responsive to the glutathione in cells.

    更新日期:2017-11-21
  • The construction of silver aggregate with inbuilt Raman molecule and gold nanowire forest in SERS-based immunoassay for cancer biomarker detection
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Tao Jiang, Xiaolong Wang, Jun Zhou, Han Jin

    Heterostructures of one-dimensional gold nanowires supported silver aggregates with a large amount of hotspots are promising for future SERS-based immunoassay. In this paper, silver aggregates with various coordination numbers were first obtained through adjusting the ligand incubation time and encapsulated by polystyrene-block-poly(acrylic acid). The SERS intensity of inbuilt Raman molecule (2-naphthalenethiol) in silver aggregates increased gradually with the increase of coordination number and the largest SERS enhancement ratio of the aggregates to single nanoparticles finally reached to 10. After decorating the silver aggregates onto the vertically aligned ultrathin gold nanowire forest, much more intensive SERS signals were observed compared with those on bare silica wafer. This promising result can be attributed to the strong surface plasmon coupling at the interface regions of the two materials that introduced multiple co-enhanced hotspots in the heterostructures. Then, the silver aggregates were modified with antibody and employed in immunoassay with immune gold nanowire forest as substrate. This SERS immunosensor exhibited a wide linear range (1 μg mL−1 to 1 fg mL−1) and an ultra-low detection limitation of 1 fg mL−1 for PSA.

    更新日期:2017-11-21
  • Facile synthesis of hollow MnFe2O4 nanoboxes based on galvanic replacement reaction for fast and sensitive VOCs sensor
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Lu Zhang, Gang Wang, Feng Yu, Yang Zhang, Bang-Ce Ye, Yingchun Li

    Hollow MnFe2O4 nanoparticles were successfully synthesized based on simple galvanic replacement reaction with Mn3O4 as a precursor. The chemical composition and nanostructure of the as-prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. MnFe2O4 was applied to decorate interdigital electrodes and the obtained sensors were used to detect fourteen kinds of volatile organic compounds at different operation temperature from 160 °C to 280 °C. Results show that the sensor has good sensitivity, repeatability and long-term stability for ethanol gas determination at 210 °C. The detection linear range for ethanol is 2 ∼ 400 ppm, and the response and the recovery time was 7.5 s and 8.0 s, respectively. Besides, the fabricated sensor also displayed decent performance in measuring n-decane in the concentration range of 2 ∼ 400 ppm at 260 °C. Finally, gas-sensing mechanism of the prepared sensor was clearly studied.

    更新日期:2017-11-21
  • Amperometric detection of salivary α-amylase on screen-printed carbon electrodes as a simple and inexpensive alternative for point-of-care testing
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Paulo T. Garcia, Luiza N. Guimarães, Anderson A. Dias, Cirano J. Ulhoa, Wendell K.T. Coltro

    This study describes the amperometric detection of salivary α-amylase (sAA) in human saliva samples using screen-printed carbon electrodes (SPCE). The proposed method was based on the indirect determination of sAA in a sequence of two chemical reactions. Basically, the first reaction is the hydrolysis of starch by sAA to produce maltose. Then, the generated reducing sugar promotes the conversion of [Fe(CN)6]3− into [Fe(CN)6]4− in a second reaction. Different parameters, such as pH, reaction time, sAA volume and starch concentration were thoroughly optimised. The best electrochemical response was found using 5 mmol L−1 NaOH (pH = 12), reaction time of 20 min, sAA volume of 15 μL and 0.5% (w/v) starch. The analytical performance revealed good linear correlation for sAA concentration levels between 100 and 1200 U mL−1. The achieved limit of detection (LOD) and sensitivity values were 1.1 U mL−1 and 10.7 μA/(log U mL−1), respectively. The proposed electrochemical sensor exhibited great selectivity. The amperometric response for sAA was recorded in the presence of different glucose levels (0.01—0.10 mmol L−1) and no noticeable change was observed. The feasibility of the proposed method was investigated through the determination of sAA levels in five human saliva samples. The concentration levels found ranged between 182.8 and 1117.1 U mL−1 and presented accuracy between 90 and 97%. The method reported herein emerges as a simple, inexpensive, portable, reliable and powerful tool for rapid point-of-care testing (POCT).

    更新日期:2017-11-21
  • An AIE based fluorescent probe for digital lifting of latent fingerprint marks down to minutiae level
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Raghupathy Suresh, Senthil Kumar Thiyagarajan, Perumal Ramamurthy

    Acridinediones, a new addition to the family of dyes having aggregation induced emission characteristics have been reported. Facile hydrophobic interactions between the acridinedione aggregates and fingerprint residues were exploited to lift the latent fingerprint marks on a non-porous substrate. By employing this preferential adhesion approach, a portable wet method for the enhancement and visualization of latent fingerprint marks using hand held UV light and mobile camera was demonstrated. Using this simple, rapid, cost effective, eco and user friendly method the latent fingerprints, its primary and secondary level of information’s can be easily decoded. These acridinedione derivatives also show strong blue luminescence in solid state with high fluorescence quantum yield.

    更新日期:2017-11-21
  • The room temperature gas sensor based on Polyaniline@flower-like WO3 nanocomposites and flexible PET substrate for NH3 detection
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Siqi Li, Pengfei Lin, Liupeng Zhao, Chong Wang, Deye Liu, Fangmeng Liu, Peng Sun, Xishuang Liang, Fengmin Liu, Xu Yan, Yuan Gao, Geyu Lu

    The Polyaniline (PANI)@flower-like tungsten oxide (WO3) nanocomposites with different mole percentages of flower-like WO3 (2–50%) were successfully synthesized by using a facile in situ chemical oxidation polymerization method and were loaded on flexible polyethylene terephthalate (PET) substrate to fabricate NH3 sensors operating at room temperature. The morphology, nanostructures and thermal degradation behavior of the as-obtained sensing materials were measured and characterized utilizing SEM, TEM, FTIR, XRD and TG. Gas-sensing performances of fabricated sensors were tested and results indicated that the sensor with PANI@10 mol.% flower-like WO3 exhibited the highest response value at approximately 20.1–100 ppm NH3 at room temperature, which is more than 6 times higher than that of pure PANI. Notably, the lowest detection limit of 500 ppb to NH3 was obtained at room temperature. Furthermore, the present sensor also showed rapid response and recovery rates of 13 s and 49 s, good repeatability, selectivity, and slight humidity effects to 10 ppm NH3 at room temperature. Moreover, the gas sensing mechanisms of PANI and nanocomposites were also discussed in detail. The enhanced sensing characteristics of nanocomposites were related to the morphology structure and p-n heterojuction between PANI and flower-like WO3.

    更新日期:2017-11-21
  • Solid glucose biosensor integrated in a multi-well microplate coupled to a camera-based detector: Application to the multiple analysis of human serum samples
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Javier Pla-Tolós, Yolanda Moliner-Martínez, Carmen Molins-Legua, Pilar Campíns-Falcó

    In the present work, a biosensor adapted in a 96-well microplate has been coupled with a smartphone-based photometer in order to develop a low-cost colorimetric multi-sample dispositive. The strength of this biosensing system is the integration of the biosensor into the 96-well microplate, and the use of a smartphone and free image analysis software as a microplate reader. The performance of the proposed biosensor has been demonstrated to determine glucose in several human serum samples. This method is simple, cost-effective, sensitive and selective for the determination of glucose in serum, with detection limits of 1.8 mg/dL and a good linearity over the range 6–88 mg/dL. Precision was also satisfactory (relative standard deviation, %RSD<5). The performance of the biosensing system has been compared with the conventional derivatization method, adding all the reagents in solution and measuring the absorption at 653 nm. Results obtained indicated that this approach simplifies significantly the analytical measurements, avoids the need to prepare derivatization reagents, is portable, and allows multiple in-situ measurements simultaneously. Thus, the simplicity of the test has been improved not only in the reaction step but also in the response measurement.

    更新日期:2017-11-21
  • Enhancing Sensitivity of Novel Hg2+ Fluorescent Sensor via Plasmonic Enhancement of Silver Nanoparticles
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Sasiwimon Kraitong, Jitnapa Sirirak, Kittibandid Soisuwan, Nantanit Wanichacheva, Pattanawit Swanglap

    Contamination of Hg2+ in an aqueous environment is dangerous for all living species including human. In this work, a new rhodamine B derivative fluorescent sensor (sensor RBS) for Hg2+ detection was successfully synthesized. In addition, the synthesized yellow silver nanoparticles (Y-AgNPs) were incorporated into sensor RBS to obtain sensor RBS + Y-AgNPs. The sensitivity studies for Hg2+ detection of the sensors showed that the Hg2+ detection limit of sensor RBS and sensor RBS + Y-AgNPs were 12.9 ppb and 0.7 ppb, respectively. The result showed that incorporation of Y-AgNPs into sensor RBS led to significantly improved Hg2+ detection limit of the sensor, which could be attribute to plasmonic enhancement of Y-AgNPs. Furthermore, the selectivity studies of the sensors showed that sensor RBS and sensor RBS + Y-AgNPs were highly selective toward Hg2+ against interference ions. We also showed that sensor RBS + Y-AgNPs could be used to detect Hg2+ in real samples. Importantly, we have demonstrated that utilization of plasmonic enhancement could improve the sensitivity of the fluorescent sensor, which could pave the way for development of portable fluorescent sensor for the on-site Hg2+ detection.

    更新日期:2017-11-21
  • Magnetically controlled immunosensor for highly sensitive detection of carcinoembryonic antigen based on an efficient “turn-on” cyanine fluorophore
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Jing Qian, Di Xu, See-Lok Ho, Kun Wang, Man Shing Wong, Hung-Wing Li

    Early cancer diagnosis is critically important for early intervention and it can significantly enhance the treatment efficacy and the chance of cure. Herein, for the first time, the cyanine fluorophore namely, SLSO3, was synthesized and found to possess a high binding affinity towards a typical biomarker, carcinoembryonic antigen (CEA) in which it served as an excellent turn-on labelling fluorophore for the detection of CEA. On this basis, the target CEA antigen is captured by a primary antibody conjugated on magnetic silica coated iron oxide nanoparticles and then followed by secondary antibody-loaded SiO2 nanoparticles, which provide more binding sites for the labelling dyes resulting in 6-fold increase in fluorescence and thus heightened sensitivity. The immunosensor is capable of differentiating target analyte from other cancer-associated proteins and has been applied to quantify CEA in human serum sample and the result was consistent to that obtained from a commercial ELISA kit. This simple and direct detection assay has achieved a low limit of detection in the pg mL−1 regime with small sample consumption (only 10 μL) and without any sample pre-treatment and purification.

    更新日期:2017-11-21
  • Rhodamine-based multianalyte colorimetric probe with potentialities as on-site assay kit and in biological systems
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Tahir Rasheed, Chuanlong Li, Yinglin Zhang, Faran Nabeel, Jiaxin Peng, Jie Qi, Lidong Gong, Chunyang Yu

    Herein, we report a new rhodamine-based multianalyte (Cu2+ and Hg2+) fluorescent sensor RH-FP. The synthesized probe acts as a dual chemosensor for recognition of Cu2+ and Hg2+ in acetonitrile-water (4:1 v/v, pH 7.2 with 10 mM, HEPES) in the presence of other miscellaneous metal cations i.e. Ag+, Al3+, Ba2+, Ca2+, Cd2+, Fe3+, Fe2+, K+, Li+, Mg2+, Mn2+, Cu+2, Pb2+, Ni2+, Na+ and Zn2+. A highly selective and sensitive colorimetric (colorless to pink) response accompanied by a significant increase in absorption and emission maxima (250-folds) was observed by the interaction of RH-FP and Cu2+ or Hg2+. This makes RH-FP a suitable “bare-eye” detector. The Job’s plot and ESI-MS confirm 1:1 binding stoichiometry between sensor RH-FP and metal cations. The calculated binding constant for the complexes (RH-FP-Cu2+ and RH-FP-Hg2+) are 3.37 × 105 mol−1 and 7.6 × 105 mol−1, with a detection limit of 3.9 nm and 2.36 nm respectively. The binding mechanism was confirmed by Fourier transform infra-red spectroscopy (FT-IR) 1H, 13C NMR and density functional theory (DFT) calculations. Moreover, the fluorescent sensor RH-FP displayed potential in-field applications as detection kit and in fluorescent imaging of biological systems to detect Cu2+ or Hg2+.

    更新日期:2017-11-21
  • Toward optimized SiOCH films for BTEX detection: impact of chemical composition on toluene adsorption
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-21
    Julien El Sabahy, Jean Berthier, Florence Ricoul, Vincent Jousseaume

    Volatile Organic Compounds are a cause of concern for human health. It is particularly the case for BTEX compounds (Benzene, Toluene, Ethylbenzene and Xylenes). Gravimetric sensors are good candidates for their detection but they have to be functionalized by a sensitive film to become active. In this work, organosilicate thin films (SiOCH) deposited by plasma enhanced chemical vapor deposition are investigated. This work aims at understanding the role of their chemical composition on gas adsorption and to propose an optimized material for BTEX detection. Through the synthesis and characterization of various SiOCH thin films, the role of hydrophobicity, carbon content and specific chemical bonding is highlighted. This led to an optimized film presenting both high affinity (partition coefficient toward toluene higher than 15000) and rapid temporal response.

    更新日期:2017-11-21
  • 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
  • Self-Healing, antibacterial and sensing nanoparticle coating and its excellent optical applications
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-16
    Hongyun Xuan, Wei Dai, Yanxi Zhu, Jiaoyu Ren, Jianhao Zhang, Liqin Ge

    Self-healing, antibacterial and metal-ion sensing coatings with nanoparticles were developed using layer-by-layer (LbL) self-assembly technique via host-guest interaction. The coatings consist of MoS2 nanosheets, beta-cyclodextrin (β-CD)-modified poly (ethylenimine) (PEI) and adamantane (AD)-modified poly (acrylic acid) (PAA). Damages to conventional coatings results in cracking and affects the coatings’ ability to maintain antibacterial and sensing qualities. The prepared MoS2/β-CD-PEI/AD-PAA self-healing coatings are not only able to greatly suppress bacterial adhesion and have excellent antibacterial property, particularly under UV light irradiation, but also have a longtime service time. Moreover, the self-healing coatings first applied the fluorescence quenching for detecting heavy metals (Co2+). Fluorescence spectra demonstrated that a linear relationship existed between the fluorescence intensity and the Co2+ concentration with 0 ∼ 0.1 ug/mL and the detection limit of Co2+ is 0.018 mg/mL. Therefore, the nanoparticle multilayer polyelectrolyte hybrid coatings have a potential application in food industries.

    更新日期:2017-11-20
  • How shell thickness can affect the gas sensing properties of nanostructured materials: Survey of literature
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-16
    Ali Mirzaei, Jae-Hun Kim, Hyoun Woo Kim, Sang Sub Kim

    High-performance gas sensors are needed to improve safety in daily life. Even though the gas sensing performance of new nanostructured metal oxides has improved significantly, some aspects of these novel nanomaterials have not been fully explored. Core-shell (C-S) and hollow shell nanostructures are two types of advanced materials for gas sensing applications. Their popularity is mainly due to the synergetic effects of the core and shell in C-S nanostructures, the high surface areas of both C-S and hollow nanostructures, and the possibility of tuning the shell thickness within the range of the Debye length for such nanostructures. In addition to the type of sensing material, morphology, sensing temperature, and porosity, shell thickness is one of the most important design parameters. Unfortunately, less attention has been paid to the effect of shell thickness on the gas sensing properties. Herein, we demonstrate that the thickness has an undeniable role in the gas sensing response of the resulting material. In this review, we present the first overview of this aspect of sensing materials. By referring to related works, we show how shell thickness can affect the sensing properties of both C-S and hollow nanostructures. Researchers in this field will be able to fabricate more sensitive gas sensors for real applications by better understanding the effect of shell thickness on the gas sensing properties of C-S and hollow nanostructured materials.

    更新日期:2017-11-20
  • A sensitive polymer dots-manganese dioxide fluorescent nanosensor for “turn-on” detection of glutathione in human serum
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-16
    Lei Han, Shi Gang Liu, Xiao Fang Zhang, Bai Xiang Tao, Nian Bing Li, Hong Qun Luo

    Glutathione (GSH), as a crucial endogenous thiol and antioxidant, plays an essential role in the biological system, and its abnormal levels are closely related to various diseases. Therefore, it continues to be of enormous significance to develop a sensitive and efficient method for the assay of GSH. Herein, we report a facile and sensitive polymer dots (PDs)-manganese dioxide (MnO2) nanosensor for turn-on assay of GSH. In this sensing system, the PDs with strongly green fluorescence were prepared by a mild one-step method using hydroquinone and ethylenediamine as precursors, and the fluorescence of PDs can be quenched by MnO2 nanosheets. The PDs-MnO2 nanosensor was the turn-off state. In the presence of GSH, however, the fluorescence of the PDs-MnO2 nanosensor can remarkably recover because MnO2 nanosheets can be reduced into Mn2+ by GSH. The PDs-MnO2 nanosensor was the turn-on state. Based on the change of the fluorescence signal from turn-off switched to turn-on, a sensitive method was successfully constructed to detect GSH. We also systematically discussed the mechanism of the PDs-MnO2 nanosensor for GSH assay, indicating that the MnO2 nanosheets-induced the fluorescence quenching was derived from inner filter effect (IFE). The PDs-MnO2 nanosensor toward GSH showed a wide linear range from 0.5 to 200 μM and high sensitivity with a limit of detection of 0.10 μM. The as-developed PDs-MnO2 nanosensor was also successfully applied to detect GSH in human serum with satisfactory results.

    更新日期:2017-11-20
  • Ultrasensitive photoelectrochemical immunosensor for insulin detection based on dual inhibition effect of CuS-SiO2 composite on CdS sensitized C-TiO2
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-16
    Xueping Wang, Picheng Gao, Tao Yan, Rongxia Li, Rui Xu, Yong Zhang, Bin Du, Qin Wei

    High sensitivity of biosensor is one of the most important factor to realize the accurate detection of biomarkers. To achieve this purpose, enhancing initial signal and amplifying the value of signal change are two main approaches. In this study, a novel signal-off photoelectrochemical (PEC) immunosensor for highly sensitive determination of insulin was developed upon dual inhibition effect of CuS-SiO2 composites toward CdS sensitized carbon doped titanium dioxide (C-TiO2/CdS). Due to the doping of carbon and sensitization of CdS, C-TiO2/CdS sensitized structure was employed as ideal photoactive matrix, which provided stable and enhanced basal signal. To achieve the amplification of signal change value, CuS-SiO2 composites were prepared and used as labels. On account of the competitively light harvesting and electron donors consuming by p-type semiconductor CuS, less light energy and electron donors arrived at the C-TiO2/CdS sensitized structure. Besides, the remarkable steric hindrance effect of CuS-SiO2 labeled secondary antibodies (CuS-SiO2-Ab2) conjugates obstructed the transfer of electrons and diffusion of the electron donors to the photoelectrode surface, leading to further decrease of photocurrent compared with the pure CuS nanoparticles. Greatly enhanced sensitivity is achieved due to the dual inhibition effect of CuS-SiO2 composites on C-TiO2/CdS. Taking advantage of the synergy effect of C-TiO2/CdS sensitized structure and dual inhibition effect of CuS-SiO2-Ab2 bioconjugates, the as-prepared immunosensor for insulin exhibited high sensitivity and good stability with a low detection limit of 0.03 pg·mL−1. Additionally, the strategy provided an efficient and simple approach for signal amplification and held great promise for other PEC immunoassay development.

    更新日期:2017-11-17
  • Dual-color quantum dots-based simultaneous detection of HPV-HIV co-infection
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-16
    Ana Maria Jimenez Jimenez, Amitava Moulick, Lukas Richtera, Ludmila Krejcova, Lukas Kalina, Rahul Datta, Marketa Svobodova, David Hynek, Michal Masarik, Zbynek Heger, Vojtech Adam

    Human papillomavirus (HPV) and human immunodeficiency virus (HIV) are closely related infections; both diseases are mutually reinforcing due to the co-infection effects, which increase their clinical and epidemiological implications, raising urgent public health concerns. In the present study, a nano-system was developed for simultaneous detection of HPV and HIV targeting E6-HPV16 and Gag-HIV genes respectively. The target sequences from the samples of the patients suffering from head and neck cancer were isolated by magnetic glass particles (MGPs) and subsequently were hybridized with a mixture of the complementary probes attached to cadmium telluride quantum dots (CdTe QDs). Finally, the specific and successful binding was determined by an easy fluorescence analyses and was corroborated by PCR and electrochemistry. Red and green CdTe QDs were used for the dual-color detection of HPV and HIV respectively. Our nano-system can be applied as a proficient tool for the identification of HPV, HIV or both diseases simultaneously, getting a successful and high sensitivity system of detection.

    更新日期:2017-11-17
  • Ultrasensitive electrochemical immunosensor for procalcitonin with signal enhancement based on zinc nanoparticles functionalized ordered mesoporous carbon-silica nanocomposites
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-15
    Yishan Fang, Qiong Hu, Xiongtao Yu, Lishi Wang

    A novel and sensitive strategy for procalcitonin (PCT) determination was developed based on zinc nanoparticles-functionalized ordered mesoporous carbon-silica nano-composites (OMCSi-Zn). This strategy combined an effectively designed trace tag and a simple immunosensor. The large amount of OMCSi-Zn materials as label greatly amplified the detection signals for the electrochemical detection of proteins, while the good biocompatibility of graphene-chitosan as sensor matrix retained excellent stability and accelerated electron transfer for the sandwich-type immunoassay. Without metal preconcentration, the zinc nanoparticles loading on the ordered mesoporous carbon-silica nano-composites (OMCSi) could directly be detected through electrochemical voltammetries, while the immunoreaction had a close relationship with the distinct voltammetric peaks. The proposed method exhibited high sensitivity and good stability for PCT detection, possessing an improved linear response range from 0.05 pg/mL to 80 ng/mL, with a detection limit of 0.013 pg/mL (S/N = 3). Moreover, the serum samples from clinic were accurately detected with the proposed method, indicating that the developed immunoassay possessed excellent potential application in clinical diagnostics for PCT.

    更新日期:2017-11-17
  • Sensitive and interference-free electrochemical determination of Pb(II) in wastewater using porous Ce-Zr oxide nanospheres
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-15
    Pei-Hua Li, Yi-Xiang Li, Shi-Hua Chen, Shan-Shan Li, Min Jiang, Zheng Guo, Jin-Huai Liu, Xing-Jiu Huang, Meng Yang

    Herein, combined the synergetic effects and excellent adsorption of binary oxides, a novel sensor interface was designed by using porous Ce-Zr oxide nanospheres modified glassy carbon electrode (Ce-Zr oxide/GCE), which has successfully realized high sensitivity and anti-interference detection of Pb(II). The electrochemical determination of Pb(II) has been investigated by square wave anodic stripping voltammetry (SWASV) range from 0.02 to 0.5 μM, and a high sensitivity per unit area of 1666.02 μA μM−1 cm−2 was obtained with a limit of detection of 0.006 μM (3σ method). The enhancement of Pb(II) stripping signal is attributed to the excellent adsorption performance of porous Ce-Zr oxide nanospheres, which has been confirmed with X-ray photoelectron spectroscopy (XPS). Importantly, Ce-Zr oxide/GCE possesses highly anti-interference ability against the influence of Hg(II), Cd(II), Cu(II), and Zn(II) in the determination of Pb(II). Meanwhile, the remarkable stability and reproducibility were obtained. Finally, the accurate analysis of Pb(II) in wastewater collected from Wangtang sewage disposal plant was achieved. These results indicate that porous Ce-Zr oxide nanospheres are identified as promising modifier for the reliable and accurate determination of Pb(II).

    更新日期:2017-11-17
  • Combination of periodic hybrid nanopillar arrays and gold nanorods for improving detection performance of surface-enhanced Raman spectroscopy
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-15
    Nak-hyeon Kim, Soogeun Kim, Munsik Choi, Hyeong-Ho Park, Nam Hoon Kim, Sang Yoon Park, Kyung Min Byun, Soo Yeol Lee

    Surface-enhanced Raman spectroscopy (SERS) based on metallic nanoparticles has suffered from poor reproducibility and line broadening of SERS signals. To overcome these problems, we newly propose the SERS substrate incorporating periodic hybrid nanopillar arrays combined with gold nanorods on a flat gold surface. Low reproducibility caused by inhomogeneously distributed and aggregated gold nanoparticles could be improved by employing periodic nanopillar arrays. In addition, we experimentally found that the hybrid nanopillar, in which a dielectric layer is sandwiched between a flat gold film and a gold nanopillar, can reduce line broadening of SERS signals significantly. In this study, the proposed SERS substrate has the potential to provide SERS signals with higher reproducibility and smaller line broadening for high-sensitivity detection of target molecules.

    更新日期:2017-11-17
  • An Electrochemical Approach Capable of Prostate Specific Antigen Assay in Human Serum Based on Exonuclease-Aided Target Recycling Amplification
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-15
    Peng Miao, Yiting Jiang, Yuanhong Wang, Jian Yin, Yuguo Tang

    In this report, an ultrasensitive electrochemical aptasensor for the detection of prostate specific antigen (PSA) in human serum is presented. DNA tetrahedron molecular layer is designed on the interface of a gold working electrode, which provides the recognition element for PSA capture. Next, exonuclease-aided target recycling amplification is performed, which determines the amount of attached silver nanoparticles (AgNPs) via silver-amino chemistry. By recording electrochemical responses from AgNPs, initial concentration of PSA can be easily evaluated. The limit of detection is pushed down to 0.11 pg mL−1, which is attributed to the cyclic digestion effect of exonuclease and highly effective electrochemical reporters of AgNPs. The efficiency and robustness of this approach are further studied using human serum samples. The achieved results are satisfactory for future clinical applications.

    更新日期:2017-11-17
  • Detection of Neurochemicals with Enhanced Sensitivity and Selectivity Via Hybrid Multiwall Carbon Nanotube-Ultrananocrystalline Diamond Microelectrodes
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-15
    Chao Tan, Gaurab Dutta, Haocheng Yin, Shabnam Siddiqui, Prabhu U. Arumugam

    Abnormal neurochemical signaling is often the underlying cause of brain disorders. Electrochemical microsensors are widely used to monitor neurochemicals with high spatial-temporal resolution. However, they rely on carbon fiber microelectrodes that often limit their sensing performance. In this study, we demonstrate the potential of a hybrid multiwall carbon nanotube (MWCNT) film modified boron-doped ultrananocrystalline diamond (UNCD) microelectrode (250 μm diameter) microsensor for improved detection of dopamine (DA) in the presence of common interferents. A series of modified microelectrodes with varying film thicknesses were microfabricated by electrophoretic deposition (EPD) and characterized by scanning electron microscopy, x-ray photoelectron spectroscopy, electrochemical impedance spectroscopy (EIS) and silver deposition imaging. Using cyclic voltammetry, the 100-nm “thin” film microelectrode produced the most favorable combination of DA sensitivity value of 36 ± 2% μA/μM/cm2 with a linear range of 33 nM to 1 μM and a limit of detection (LOD) of 9.5 ± 1.2% nM. The EIS spectra of these microelectrodes revealed three regions with inhomogeneous pore geometry and differing impedance values and electrochemical activity, which was found to be film thickness dependent. Using differential pulse voltammetry, the modified microelectrode showed excellent selectivity by exhibiting three distinct peaks for the DA, serotonin and excess ascorbic acid in a ternary mixture. These results provide two key benefits: first, remarkable improvements in DA sensitivity (>125-fold), selectivity (>2000-fold) and LOD (>180-fold), second, these MWCNTs can be selectively coated with a simple, scalable and low cost EPD process for highly multiplexed microsensor technologies. These advances offer considerable promise for further progress in chemical neurosciences.

    更新日期:2017-11-17
  • SnO2 (n)-NiO (p) composite nanowebs: gas sensing properties and sensing mechanisms
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-15
    Jae-Hun Kim, Jae-Hyoung Lee, Ali Mirzaei, Hyoun Woo Kim, Sang Sub Kim

    Aiming to optimize SnO2-NiO nanocomposite sensors for detection of hazardous gases, a series of xSnO2-(1-x) NiO composite nanowebs with different compositions (x = 0.1, 0.3, 0.5, 0.7, and 0.9) were synthesized using an electrospinning process. The formation of long and continuous SnO2-NiO nanowebs was verified. Depending on the composition, xSnO2-(1-x) NiO composite nanowebs‎ showed either n-type (SnO2-rich composition) or p-type (NiO-rich composition) gas-sensing behavior. The best sensing performance was obtained for the nanowebs of 0.5SnO2-0.5NiO. The presence of plenty of p-n heterojunctions along with the high oxygen adsorption property of NiO were the main reasons for the high response to the NO2 and C6H6 gases at this optimized composition.

    更新日期:2017-11-17
  • A Silver-Grafted Sponge as an Effective Surface-Enhanced Raman Scattering Substrate
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-14
    Ningning Zhou, Guowen Meng, Chuhong Zhu, Bin Chen, Qitao Zhou, Yan Ke, Dexian Huo

    A silver film is in situ grafted on a melamine sponge via the silver mirror reaction. The porous structure of the sponge possesses an enlarged total SERS-active surface area without increasing the overall footprint of the SERS substrate. The Ag-grafted sponge exhibits high SERS activity toward Rhodamine 6G with a concentration down to 0.1 pM. Moreover, the sponge-based substrate also offers a good signal uniformity and reproducibility with a relative signal deviation down to 11.7% and 13.2%, respectively. Furthermore, the Ag-grafted sponge exhibits a limit of detection of 4.23 nM toward adenine and 1.88 nM toward thiram in the aqueous solution by a handheld portable Raman spectrometer. The inexpensive and simple Ag-grafted sponge can be used as an effective SERS substrate, which will find the potential application in field-deployable detection of organic pollutants in the aquatic environment.

    更新日期:2017-11-15
  • Monitoring uniform and localised corrosion by a radiofrequency sensing method
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-14
    M. Yasri, B. Lescop, E. Diler, F. Gallée, D. Thierry, S. Rioual

    A new method for atmospheric corrosion monitoring based on the variation of radiofrequency (RF) wave propagation in a resonator during its corrosion is presented. The ability of the proposed sensor to differentiate between uniform and localized corrosion mechanisms is demonstrated by considering two identical open stub microstrip resonators produced in zinc and aluminum materials, respectively. For that purpose, experimental characterization of electromagnetic wave propagation in the resonators and simulations are compared. The proposed sensitive resonator should therefore be considered as the key element of new corrosion mimetic sensors.

    更新日期:2017-11-15
  • Zeolite membranes for highly selective formaldehyde sensors
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-12
    Andreas T. Güntner, Sebastian Abegg, Karsten Wegner, Sotiris E. Pratsinis

    A major challenge in gas sensing (e.g. breath analysis, indoor air quality monitoring, etc.) is the accurate detection of trace-level species in complex mixtures. While modern chemical gas sensors can be extremely compact, inexpensive and highly sensitive, their success is still limited by selectivity. Here, we combine sensors with highly selective zeolite membranes pre-separating gas mixtures. Zeolites – broadly applied in catalysis and gas separation – effectively separate molecules based on kinetic diameter, sorption and diffusion characteristics. Therefore, zeolite membranes are suitable filters for gas sensors removing undesired species from mixtures like exhaled breath. As proof-of-concept, a zeolite Mobile-Five (MFI)/Al2O3 membrane is placed upstream a highly sensitive but non-selective Pd-doped SnO2 sensor. Their combination exhibits exceptional selectivity (>100) for formaldehyde (down to 30 ppb) at 90% relative humidity, outperforming state-of-the-art detectors by more than an order of magnitude. This novel concept is readily extendable to other tracers, as many combinations of widely tunable microporous membranes and gas sensors can be realized in this modular sensing device. This could enable a new class of highly sensitive and selective portable breath detectors or compact indoor air monitors.

    更新日期:2017-11-13
  • Zinc peroxide combustion promoter in preparation of CuO layers for conductometric CO2 sensing
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-12
    N.B. Tanvir, O. Yurchenko, E. Laubender, R. Pohle, O.v. Sicard, G. Urban

    The detection of CO2 has applications for both industrial and domestic use due to its high exposure effects on the human health. Conductivity sensors on the other hand, present a cost-effective approach that can be successfully utilized for the detection of CO2. However, the integration of metal oxide based nanoparticles layers for conducometric sensing is complicated and requires improvement in the layer quality to achieve effective and stable gas sensing properties. Addressing this challenge, we present in this work, p-type semiconducting CuO nanoparticles as a CO2 gas sensitive material and introduce a combination of organic binder and peroxide such as ZnO2 for improved gas sensitive layer quality. The addition of ZnO2 to CuO nanoparticles enables the layers annealing at 300 °C which makes the preparation method compatible to silicon based gas sensing devices. For the characterization of layers, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis and Fourier transform infrared measurements are employed. The CO2 gas sensing measurements show a reversible change in resistance suggesting hybrid nanoparticles layers as an efficient gas sensitive material. The measurements performed at different humidity levels for CuO-ZnO2 (10:1) layer indicate different sensing mechanism for dry conditions in comparison to the measurements performed under humid atmosphere. The Lewis acid-base reaction between oxide oxygen and CO2 has been proposed as sensing mechanism for the measurements in dry air, whereas the formation of surface barriers between nano-grains due to the reaction with CO2 has been suggested for the CO2 response under humid conditions.

    更新日期:2017-11-13
  • Effect of Glass Former (B2O3, SiO2, GeO2 and P2O5) Addition to Fe2O3-Bi2O3 Glass on pH Responsivity
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-12
    Tadanori Hashimoto, Hiromu Inukai, Kotaro Matsumura, Hiroyuki Nasu, Atsushi Ishihara, Yuji Nishio

    The effect of glass former (constituent capable to vitrify by itself such as B2O3, SiO2, GeO2 and P2O5) addition to Fe2O3-Bi2O3 (FeBi) glass on pH responsivity (pH sensitivity and pH response time) was investigated in order to develop novel pH responsive, hydrophobic glasses. Additionally, the effect of glass composition on pH sensitivity of Fe2O3-Bi2O3 glasses was investigated in order to develop contaminant-free reference electrodes with very low pH sensitivity. A small amount of B2O3 and SiO2 drastically increased the pH sensitivity. The addition of glass formers of 20 mol% provided high pH sensitivity (>90%) in any of the glass formers. Although all glass formers increased their contact angle with water for Fe2O3-Bi2O3 glass, the addition of GeO2 was most effective. Most of the Fe2O3-Bi2O3-GeO2 (FeBiGe) glasses with 20–30 mol% GeO2, which serve as a working electrode, had compatibility between high pH sensitivity and a high contact angle with water (100°). However, certain Fe2O3-Bi2O3 glasses with approximately 20 mol% Fe2O3 showed low pH sensitivity (<10%). These FeBi glasses are considered to serve as contaminant-free reference electrodes, whereas KCl aqueous solution, as a contaminant, gradually leaks in commercial reference electrodes (Ag/AgCl immersed in KCl aqueous solution). Since the novel pH complex glass electrodes, consisting of a FeBiGe working electrode and a FeBi reference electrode, resist fouling of itself and serve as contaminant-free glass electrodes, these electrodes are expected to be highly useful in biological systems and drug development.

    更新日期:2017-11-13
  • A ratiometric fluorescent probe for formaldehyde in aqueous solution, serum and air using aza-cope reaction
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Yang Zhou, Jiaying Yan, Nuonuo Zhang, Dejiang Li, Shuzhang Xiao, Kaibo Zheng

    Developing simple and selective methods for formaldehyde (FA) detection is of great interest, because FA is not only an environmental pollutant, but also an endogenous bioactive molecule. Herein, a new ratiometric fluorescent probe (HBT-FA) based on aza-Cope reaction was designed and synthesized, which showed high selectivity and ratiometric fluorescence response to FA. Furthermore, the probe could detect FA in various medium, such as aqueous solution, serum and air.

    更新日期:2017-11-13
  • Improved LRET-based detection characters of Cu2+ using sandwich structured NaYF4@NaYF4:Er3+/Yb3+@NaYF4 nanoparticles as energy donor
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Yanqiu Zhang, Sai Xu, Xiangping Li, Jinsu Zhang, Jiashi Sun, Lili Tong, Hua Zhong, Haiping Xia, Ruinian Hua, Baojiu Chen

    Upconversion nanoparticles (UCNPs) are widely used as energy donors via a luminescence resonance energy transfer (LRET) technique in biosensing field. To enhance LRET efficiency and afford an improved sensitivity for Cu2+ detection, sandwich structured NaYF4@NaYF4:Er3+/Yb3+@NaYF4 UCNPs have been designed and prepared. For the core-internal shell-external shell structure, luminescence ions (Er3+) are located in the internal shell near the nanoparticle surface, which is close enough to energy acceptors outside. To study the sensing properties, the UCNPs are used as energy donors and rhodamine B hydrazide (RBH) as energy acceptors to construct the nanoprobes. It is found that the sandwich structured nanoparticles gains more intense luminescence than the naked NaYF4:Er3+/Yb3+ UCNPs, which is beneficial to the further improvement of signal sensitivity in biological detection. Moreover, the specificity for detecting Cu2+ is also checked and found that the designed probe is much more sensitive to Cu2+ than the other ions including K+, Na+, Li+, Ca2+, Ba2+, Mg2+, Zn2+ and Sr2+. The experiment on the stability of UCNPs-RBH probe and RBH shows the 980 nm laser produces less photodamage to RBH than that of visible light. Therefore, the UCNPs can be used to construct potential probes for realizing effective detection of Cu2+.

    更新日期:2017-11-13
  • Low Toxic Fluorescent Nanoprobe Applicable for Sensing pH Changes in Biological Environment
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Lihua Lu, Chenfu Liu, Guodong Li, Li-Juan Liu, Chung-Hang Leung, Dik-Lung Ma

    A novel graphene oxide (GO)-based pH sensor was designed and prepared through covalently attaching a zwitterionic betaine molecule onto a GO surface. This betaine-modified GO (BMGO) exhibited high water solubility and low toxicity. In aqueous media, BMGO displayed increased fluorescence in acidic conditions and decreased fluorescence in basic conditions. BMGO possesses a pH sensing range from 4 to 12 with excellent reversibility, quick response and high stability. With its high sensitivity and robustness, BMGO can be used to monitor the pH of intracellular contents, as demonstrated through cell imaging.

    更新日期:2017-11-13
  • Yolk-shelled ZnCo2O4 microspheres: surface properties and gas sensing application
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Nirav Joshi, Luís F. da Silva, Harsharaj S. Jadhav, Flavio M. Shimizu, Pedro H. Suman, Jean-Claude M’Peko, Marcelo Ornaghi Orlandi, Jeong Gil Seo, Valmor R. Mastelaro, Osvaldo N. Oliveira Jr

    The need to improve the sensitivity, selectivity and stability of ozone gas sensors capable of monitoring the environment to prevent hazard to humans has sparked research on binary metal oxides. Here we report on a novel ozone gas sensor made with ca. 0.5 μm yolk-shelled ZnCo2O4 microstructures synthesized via an eco-friendly, co-precipitation method and subsequent annealing. With these ZnCo2O4 microspheres, ozone concentrations down to 80 parts per billion (ppb) could be detected with a.c. and d.c. electrical measurements. The sensor worked within a wide range of ozone concentrations, from 80 to 890 ppb, being also selective to ozone compared to CO, NH3 and NO2. The high performance could be attributed to the large surface area to volume ratio inherent in yolk-shell structures. Indeed, ozone molecules adsorbed on the ZnCo2O4 surface create a layer of holes that affect the conductivity, as in a p-type semiconductor. Since this mechanism of detection is generic, ZnCo2O4 microspheres can be further used in other environment monitoring devices.

    更新日期:2017-11-13
  • Synthesis of molecularly imprinted polymer on carbon quantum dots as an optical sensor for selective fluorescent determination of promethazine hydrochloride
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Ali A. Ensafi, Parisa Nasr-Esfahani, B. Rezaei

    An optical sensor based on carbon quantum dots (CQDs) coated with molecularly imprinted polymers (MIPs) was fabricated for selective and sensitive determination of promethazine hydrochloride (PrHy). Water-soluble and fluorescent CQDs were synthesized by a simple, low cost and green approach using orange juice as a carbon source. The special advantage of the synthesized CQDs with this method is low toxicity. The surface of the CQDs was covered with MIPs matrix (CQDs-MIPs) via sol-gel polymerization. For characterization of the CQDs and CQDs-MIPs, UV–vis absorption spectroscopy, fluorescence spectroscopy, dynamic light scattering technique, X-ray diffraction technique, Fourier transform infrared spectroscopy, and transmission electron microscopy were used. The fluorescence intensity of CQDs-MIPs exhibited linear response with the concentration of PrHy in the range from 2.0 to 250 μmol L−1 with a detection limit of 0.5 μmol L−1. The reproducibility of the method was checked for 20 μmol L−1 of PrHy, and the results showed RSD% as 5.1. This sensor was used for determination of PrHy in real samples and showed satisfactory results.

    更新日期:2017-11-13
  • A Red Fluorescence Probe Based on Naphthalene Diimide for Selective Detection of Sulfide by Displacement Strategy
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Luyi Zong, Mingkang Zhang, Yuchen Song, Yujun Xie, Jun feng, Qianqian Li, Zhen Li

    By using displacement strategy, a red fluorescence probe based on naphthalene diimide (NDI) can report the presence of sulfide anion with high selectivity and sensitivity, and the detection limit achieved as low as 8.7 μM. The fluorescence response with “on” or “off” state is mainly due to the different kinds of excited states by coordination, which is related to the twisted intramolecular charge transfer (TICT) process.

    更新日期:2017-11-13
  • Honeycomb structured porous films from a platinum porphyrin-grafted poly(styrene-co-4-vinylpyridine) copolymer as an optical oxygen sensor
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Yongyun Mao, Zhipeng Mei, Jiayue Wen, Gang Li, Yanhong Tian, Bingpu Zhou, Yanqing Tian

    The rational design and realization of revolutionary sensing films for improving the sensitivity and photo-stability of oxygen sensors have been long-standing challenges. We presented a facile approach for the fabrication of honeycomb structured porous films for optical oxygen sensors using a platinum porphyrin-grafted poly(styrene-co-4-vinylpyridine) (PtTFPP-PSVP) copolymer. Honeycomb porous films were prepared by the “Breath figure method”, which provides an efficient and cost-effective method to produce highly ordered honeycomb patterns in PtTFPP-PSVP copolymer films at sub-micrometer dimensions. Importantly, the application of these ordered honeycomb structured porous films as oxygen sensors afford exceptional improvement in sensitivity performance and exhibited 200% higher sensitivity than the solid sensing film owing to the higher accessibility of gas molecules and larger specific surface area. Furthermore, the photo-bleaching of sensor molecules for PtTFPP grafted to PSVP copolymer films could also be effectively alleviated and the sensors’ photo-stability was significantly improved compared with the physically incorporated PtTFPP into the same PSVP copolymer. Interestingly, the remarkably light intensity-changing characteristic of the sensing film under lower O2 partial pressures facilitates convenient identification of O2 concentrations even with the naked eye. We believe that the proposed honeycomb structured porous film could be a promising candidate in various oxygen sensing fields such as nearly anoxic systems, unsteady pressure measurements and unsteady flow visualization, etc. Additionally, the “Breath figure method”, owing to its simplicity, high reproducibility and easy processability, is expected to be readily applicable to a rich variety of other high performance gas sensor devices.

    更新日期:2017-11-13
  • Inositol directed facile “green” synthesis of fluorescent gold nanoclusters as selective and sensitive detecting probes of ferric ions
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Mohamed Ibrahim Halawa, Fengxia Wu, Anaclet Nsabimana, Baohua Lou, Guobao Xu

    In this paper, we developed one-pot facile synthetic approach for preparing fluorescent gold nanoclusters (AuNCs) by utilizing reducing-cum-stabilizing inositol (INOS). The as-prepared INOS protected gold nanoclusters (INOS@AuNCs) have excellent monodispersity with uniform size <2.0 nm and exhibit strong inherent fluorescence at 470 nm with a decay time of 12.01 ns. Interestingly, ferric ions (Fe3+) can significantly quench the fluorescence of the synthesized INOS@AuNCs leading to the efficient Fe3+ sensing. On the basis of results obtained from high-resolution transmission electron microscopy (HRTEM), an aggregation-induced fluorescence quenching mechanism was proposed. Based on these fascinating findings, a facile, fast, “green” and highly sensitive AuNCs-dependant fluorescent sensor probe was developed to detect Fe3+ ions in water resources and over-the-counter medicines. Stern-Volmer plot showed a good linear calibration curve for Fe3+ assay in the range of 1.0–1000 μM (R2 = 0.996) and good precision response to 100.0 μM Fe3+ with RSD of 2.94% (n = 3) was also achieved. The obtained limit of detection of 0.54 μM for the determination of Fe3+ ions is 10 times lower than the limit value (≈ 5.5 μM) allowed by the U.S. Environmental Protection Agency in drinkable water, indicating the sensitivity of the fluorescent probe of Fe3+ sensing. The excellent selectivity obtained among 16 types of metal ions underpins INOS@AuNCs as a promising sensor for real time detection of Fe3+ in environmental water samples and pharmaceutical tablets.

    更新日期:2017-11-13
  • Morphology-controlled synthesis of Bi2S3 nanorods-reduced graphene oxide composites with high-performance for electrochemical detection of dopamine
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-11
    Xiaoyi Yan, Yue Gu, Cong Li, Bo Zheng, Yaru Li, Tingting Zhang, Zhiquan Zhang, Ming Yang

    Bi2S3 nanorods anchored over reduced graphene oxide (rGO/Bi2S3) were successfully synthesized via a one-pot hydrothermal process, where in-situ generation of Bi2S3 nanorods and reduction of GO occurred simultaneously. Moreover, the controlled synthesis of rGO/Bi2S3 nanocomposite with tunable size was achieved by adjusting the dosage of GO. The nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy, respectively. Because of the particular construction of as-prepared nanocomposite and the synergistic effect between rGO sheets and Bi2S3 nanorods, the rGO/Bi2S3 film can effectively accelerate electron transport and extend catalytic active sites, leading to the remarkable electrochemical performance for dopamine sensing. The rGO/Bi2S3-1/GCE sensor exhibited excellent electrocatalytic activity toward the dopamine oxidation with a wide linear range of 0.01–40 μM and a low detection limit of 12.3 nM. Furthermore, the as-prepared sensor could be feasibly applied to detect dopamine in urine samples. Hence, the prepared rGO/Bi2S3 composite is one of the low cost, extremely promising and nontoxicity materials for electrocatalysis and relevant fields.

    更新日期:2017-11-13
  • An azamacrocycle functionalized GaAs (100) optical sensor for copper ion (II) detection in phosphate buffered saline solution
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-10
    Xiaohuan Huang, Peng Xia, Biyun Liu, Hua Huang

    Copper ion is important in natural and biological processes. The present work describes the fabrication of a hybrid GaAs sensor for the label-free detection of copper ion in the near infrared region. The implemented sensing strategy relies on the sensitivity of the GaAs photoluminescence (PL) emission to the local environment at its surface. Specifically, GaAs (001) substrates were chemically passivated with carboxylic acid group terminated thiols, followed by the surface functionalization with artificial Me2Cyclen cavity by a classical EDC/NHS coupling reaction. Due to a specific recognition between Me2Cyclen and copper ions, CuII were coordinately captured onto the surface. The positive charges tended to deplete electrons from the near surface region and increase the band bending, leading to a PL decrease. The selectivity of the chip towards metallic ions was further confirmed by a combination of X-ray photoelectron spectroscopy and water contact angle measurements. Collectively, the results described within suggest the promise of integrating well-designed organic scaffold with the unique optical properties of III–V semiconductors for a label-free detection of various analytes.

    更新日期:2017-11-10
  • High-Performance Transparent Actuator made from Poly(dimethylsiloxane)/Ionic Liquid Gel
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-10
    Naohiro Terasawa

    This paper presents the development of a new transparent actuator prepared from poly(dimethylsiloxane)/ionic liquid (PDMS/IL) gel electrolyte. The gel electrolyte film is prepared using a casting method and thin electrodes are applied by spray coating. Subsequently, the electrochemical and electromechanical properties of the PDMS/IL gel electrolyte actuator are investigated, which reveal its superior strain performance. The functioning mechanism of the actuator appears to originate from both the electrostatic double-layer capacitor (EDLC) and Faradaic capacitor (FC) mechanisms, with greater contribution of the former. These transparent, flexible, and robust films may have significant potential as actuator materials for wearable and transparent electronic and energy-conversion devices.

    更新日期:2017-11-10
  • Development and label-free investigation of logic-gating biolayers for smart biosensing
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-10
    Alexey V. Orlov, Averyan V. Pushkarev, Elizaveta N. Mochalova, Petr I. Nikitin, Maxim P. Nikitin

    Smart materials that can autonomously implement sensing, analyze information and execute a pre-programmed action are extremely attractive for advanced biosensing and theranostics. Recently, novel smart “biocomputing” nanoagents have emerged, which exhibit remarkable ability to adapt their behavior to changes in microenvironment. These agents use Boolean logic for simultaneous processing of complex combinations of several biochemical stimuli. One of the major challenges in design of such nanoagents is development of biocomputing sensing interfaces and their tuning for proper logic-gating characteristics. Here, we present a versatile method for precise, rapid and controllable design of smart logic-gating layers by means of a label-free optical instrument. We demonstrate real-time monitoring and control of every stage of the logic gating at a molecular level with detailed study of kinetic parameters of interactions between all participating components. Such label-free investigation is exceptionally valuable for fine tuning of the layers’ components for logic-gating biosensing. We show that direct translation onto gold nanoparticles of the optimized smart biolayers, which implement basic YES and NOT logic gates, yields intelligent labels for lateral flow immunoassay. The proposed method is promising for development of advanced biosensors and theranostic agents based on smart biolayers, which can “make decisions” as a result of complex analysis of various biochemical cues.

    更新日期:2017-11-10
  • Synthesis of Gold nanoparticles stabilized by a Pyrazinium thioacetate ligand: A new colorimetric nanosensor for detection of heavy metal Pd(II)
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-10
    Ayaz Anwar, Aaliya Minhaz, Naveed Ahmed Khan, Katayoon Kalantari, Amalina Binti Muhammad Afifi, Muhammad Raza Shah

    We developed a facile method for the synthesis of Gold nanoparticles (AuNPs) stabilized by cationic 1-(3-(acetylthio)propyl)pyrazin-1-ium ligand denoted as APP. Gold nanoparticles stabilized by APP (APP-AuNPs) are found to be polydispersed in size and lie in the range of 5–10 nm. We report a robust and sensitive protocol for the detection of heavy toxic metal ion Pd(II) in water using APP-AuNPs. From the fifteen salts tested, APP-AuNPs demonstrated a sensitive and selective spectrophotometric signal, as well as naked eye indication for recognition of Pd(II) ions. Pd(II) ions caused a colorimetric, distinguished response to APP-AuNPs based on the aggregation induced decrease of surface plasmon resonance (SPR) band. The nanosensor probe displayed a sensitive response to the Pd(II) ions in a wide range of concentration and pH, with detection limit of as low as 4.23 μM. Furthermore, the decrease in SPR band of APP-AuNPs due to Pd(II) ions was unaffected by tap water samples and/or human blood plasma.

    更新日期:2017-11-10
  • Bacteria repellent layer made of flagellin
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-10
    Boglarka Kovacs, Daniel Patko, Agnes Klein, Balazs Kakasi, Andras Saftics, Sandor Kurunczi, Ferenc Vonderviszt, Robert Horvath

    The development of bacteria repellent surface coatings is critical in various fields ranging from biosensing to health care, biotechnology and food production. In the present study we exploit that the protein flagellin rapidly forms a dense and oriented monolayer on hydrophobic surfaces upon adsorption from aqueous solution. This oriented layer mimics the surface of bacterial flagellar filaments and has excellent bacteria repellent properties. In situ OWLS (Optical Waveguide Lightmode Spectroscopy) measurements were used to monitor on-line both the formation of the protein layer on the silanized sensor surface and subsequent bacterial adhesion. The adhered cells were also visualized by fluorescent microscopy and the formed protein film was characterized by AFM (Atomic Force Microscopy). In parallel control experiments, the adherence of bacteria was measured on bare hydrophobic surfaces as well. Both OWLS and microscopy results well confirmed that the flagellin coating drastically reduced the adhesion of E. coli cells. Therefore, a novel type of bacteria repellent layer made of flagellin is demonstrated.

    更新日期:2017-11-10
  • A Review on Advances in Application of Polyaniline for Ammonia Detection
    Sens Actuators B Chem. (IF 5.401) Pub Date : 2017-11-10
    Nicolas R. Tanguy, Michael Thompson, Ning Yan

    Recently, there is an increasing interest in ammonia sensing and detection for a wide range of applications, including food, automotive, chemical, environmental, and medical sectors. A major challenge is to obtain selective, sensitive and environmentally stable sensing polymer/chemical materials that can meet the stringent performance requirements of these application areas. Among various polymer-based sensing materials, polyaniline has emerged as a preferred choice owing to its cost-effectiveness, facile preparation steps, and superior sensing performance towards ammonia.In this review, advances in polyaniline based ammonia detection sensors are summarized, with a special focus on progresses in polyaniline modification techniques to achieve enhanced sensing performance. These techniques utilize interfacial and high dilution syntheses, multifunctional dopants, template synthesis, self-oxidizing template synthesis, etc., methods Most up-to-date developments in combining polyaniline with other ammonia sensing materials, including polyaniline nanocomposites with metal oxides, graphene, carbon nanotubes and other carbon nanomaterials, are included. These novel nanocomposites have special capabilities of forming p-n nanojunctions or electron interphase interactions for superior detection sensitivity and selectivity. In addition, existing challenges toward understanding, reproducing, and optimizing the design of polyaniline based ammonia sensors are discussed.

    更新日期:2017-11-10
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.
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