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To evaluate the effect of sonication, repeated freeze-thaw cycles, calcium salt solution and their combination on the content of related growth factors (GFs) released by platelet rich plasma (PRP).Twenty PRPs from healthy blood donors were divided into 9 groups, including sonication group, freeze-thaw group, calcium gluconate group, calcium chloride group, sonication + calcium gluconate group, sonication + calcium chloride group, freeze-thaw + calcium gluconate group, freeze-thaw + calcium chloride group, and sonication + freeze-thaw group. After PRP activated by above 9 methods, the content of transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor (VEGF), and platelet-derived growth factor-BB (PDGF-BB) were detected by ELISA.The platelet concentration of the samples was (966.7±202.6)×10Among the 9 activated methods of PRP, there is no difference between two calcium salt solutions. And the combination of repeated freeze-thaw cycles and sonication may be the best treatment method to promote PRP to release GFs, while calcium gluconate is the weakest way.不同处理方式对富血小板血浆相关生长因子的影响.探究超声、冻融、钙离子及其组合等处理方法对富血小板血浆（PRP）释放生长因子含量的影响.20份PRP来自健康献血者，根据不同处理方式将每份分为9组，即超声组、冻融组、葡萄糖酸钙组、氯化钙组、超声+葡萄糖酸钙组、超声+氯化钙组、冻融+葡萄糖酸钙组、冻融+氯化钙组、超声+冻融组，采用ELISA检测每组处理后的PRP中转化生长因子β1（TGF-β1）、血管内皮生长因子（VEGF）、血小板衍生生长因子BB（PDGF-BB）的含量.样本的血小板浓度为(966.7±202.6)×109种PRP处理方式中，两种钙离子激活剂无差异；反复冻融及超声处理可能是促进PRP释放生长因子的最佳方式，葡萄糖酸钙则是作用最弱的方式.

Hexavalent chromium (Cr(VI)) pollution is a global problem, and the reduction of highly toxic Cr(VI) to less toxic Cr(III) is considered to be an effective method to address Cr(VI) pollution. In this study, low-toxicity carbon quantum dots (CQDs) were used to reduce Cr(VI) in wastewater. The results show that CQDs can directly reduce Cr(VI) at pH 2 and can achieve a reduction efficiency of 94% within 120 min. It is observed that under pH higher than 2, CQDs can activate peroxymonosulfate (PMS) to produce reactive oxygen species (ROS) for the reduction of Cr(VI) and the reduction efficiency can reach 99% within 120 min even under neutral conditions. The investigation of the mechanism shows that the hydroxyl groups on the surface of CQDs can be directly oxidized by Cr(VI) because of the higher redox potential of Cr(VI) at pH 2. As the pH increases, the carbonyl groups on the surface of CQDs can activate PMS to generate ROS, O

The reclamation and removal of organic pollutants are difficult issues of world concern. In this study, a microwave-induced reaction system (MIRS) is applied to synthesize the multifunctional composite of Fe

A direct immersion solid-phase microextraction method for determining tetracyclines (TCs) was developed by coupling with high-performance liquid chromatography. A carbon aerogel (CA) was synthesized as a fiber coating with high extractive properties and a low density of 0.1855 g cm-3via ambient pressure drying and carbonization. The as-synthesized CA exhibited a high specific surface area and a cross-linked structure; it was characterized via scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller analysis, etc. The extraction performance for six TCs was investigated, and the main experimental parameters were optimized by the Box-Behnken design. Adsorption kinetics, Langmuir and Freundlich models were used to clarify the extraction mechanism. This method showed wide linear ranges of 1-500 μg L-1, low limits of detection of 0.52-1.05 μg L-1, good repeatability of 1.37-12.47%, and satisfactory inter-fiber reproducibility of 8.51-15.81% relative standard deviation for the detection of six TCs. Moreover, this study provided an interesting insight into the detection of TCs residues in food samples.

The major problem in arsenic (As(III)) removal using adsorbents is that the method is time-consuming and inefficient owing to the fact that most of the adsorbents are more effective for As(V). Herein, we report a new discovery regarding the significant simultaneous oxidation and sequestration of As(III) by a heterogeneous catalytic process of copper aluminate (CuAl2O4) coupled with peroxymonosulfate (PMS). Oxidation and adsorption promote each other. With the help of the active radicals, the As(III) removal efficiency can be increased from 59.4 to 99.2% in the presence of low concentrations of PMS (50 μM) and CuAl2O4 (300 mg/L) in solution. CuAl2O4/PMS can work effectively in a wide pH range (3.0-9.0). Other substances, such as nitrate, sulfate, chloride, carbonate, and humic acid, exert an insignificant effect on As(III) removal. Based on X-ray photoelectron spectroscopy (XPS) analysis, the exposed reductive copper active sites might drive the redox reaction of Cu(II)/Cu(I), which plays a key role in the decomposition of PMS and the oxidation of As(III). The exhausted CuAl2O4 could be refreshed for cycling runs with insignificant capacity loss by the combined regeneration strategy because of the stable spinel structure. According to all results, the CuAl2O4/PMS with favorable oxidation ability and stability could be employed as a promising candidate in real As(III)-contaminated groundwater treatment.

Bifunctional heterogeneous catalytic processes for highly efficient removal of arsenic (As(III)) are receiving increased attention. However, the agglomerated nature and stability of nanoparticles are major concerns. Herein, we report a new process regarding the anchoring of CuFe2O4 nanoparticles on a substrate material, a kind of Fe–Ni foam, to form porous CuFe2O4 foam (CuFe2O4-foam) by in situ synthesis. The prepared material was then applied to activate peroxymonosulfate (PMS) for fast and efficient removal of As(III) from water. The results of removal experiments show that the complete removal of arsenic (

Magnetic GO/Fe3O4 was synthesized using co-precipitation of Fe2+ and Fe3+ composited with graphene oxide (GO) in alkaline conditions. SEM, XPS, FTIR, N2 adsorption and VSM techniques were employed to characterize the surface peculiarities of GO/Fe3O4 and it was then used for removal of malachite green (MG). The key influencing factors on adsorption, such as mass ratio of GO, pH value and dosage of GO/Fe3O4, were investigated. The Freundlich isotherm was well fitted to the experimental data, suggesting GO/Fe3O4 has more than one type of reactive site. By comparing the adsorption of anionic dyes and cationic dyes onto GO/Fe3O4, it was concluded that GO/Fe3O4 could be extensively applied to take up cationic dyes mainly for electrostatic interaction. In addition, the spent GO/Fe3O4 was almost 100% recovered in a water bath at 80 °C. An ultraviolet-visible (UV-vis) spectrophotometer and an atom adsorption spectrophotometer (AAS) were used to determine leached GO and Fe ions discharged into the treated solutions. Low leaching showed that magnetic GO/Fe3O4 is a stable environmentally-friendly material.

In this study, an oxygen self-doped carbon aerogel (ODCA), synthesized via ambient pressure drying and carbonization, was employed as solid-phase microextraction (SPME) coating material for phthalate esters (PAEs) detection in water samples by gas chromatography (GC) coupled with a flame ionization detector (FID). The materials were obtained by incomplete carbonization of the phenolic aerogel at a controlled temperature of 950°C, which leads to a certain amount of oxygen self-doping in the carbon aerogel. The ODCA-coated fiber exhibited fascinating extraction properties for PAEs mainly due to its oxygen active sites, π-π interaction, high surface area, and porosity of carbon aerogel. This as-proposed fiber showed wide linearity ranges (0.5–500, 1.0–500, 1.0–1000, 2.0–500 μg L−1, respectively), and provided low limits of detection (LOD, 0.17–0.83 μg L−1) for PAEs analysis under the optimal conditions. The single fiber and fiber-to-fiber relative standard deviations at 100 μg L−1 were observed in the range of 5.31%–10.37% and 9.17%–16.65%, respectively. Moreover, this method was also used for the determination of five PAEs in real water samples.

RNA, with a structure similar to DNA, should exhibit similar behaviors when it interacts with graphene. In this work, we designed a sensing platform of theophylline based on the interaction of an RNA aptamer with graphene oxide (GO) using the fluorescence as a sensing signal. Firstly, quantum dots (QDs) were modified with the selected ssRNA that can be used as an aptamer to recognize the theophylline. The fluorescence of QDs will be quenched in the presence of GO due to the noncovalent assembly between ssRNA aptamer and GO, leading to fluorescence resonance energy transfer (FRET) from QDs to GO, fluorescence "turn-off". Then, in the presence of theophylline, the ssRNA aptamer recognizes theophylline to form a dsRNA-theophylline complex. The weak affinity between the complex and GO makes QDs move away from the GO surface, leading to the fluorescence recovery of QDs, fluorescence "turn-on". Because of the high fluorescence quenching efficiency, unique structure of GO and specificity of the RNA aptamer, the proposed sensing platform exhibits high sensitivity and excellent selectivity for the determination of theophylline. The excellent performance of the sensor based on GO provides new opportunities for sensitive and selective detection of biorecognition events.

A signal-on photoelectrochemical (PEC) biosensing platform was developed here for the highly sensitive detection of a cancer marker type IV collagenase, which relied on the exciton energy transfer (EET) between CdTe quantum dots (QDs) and Ag nanoparticles (NPs) combined with the catalytic hydrolysis of a protease. A special sequence peptide chain with positively charged arginines at one end and a cysteine-labeled terminal at the other end, which could be modified with Ag NPs, was designed and synthesized. CdTe QDs and synthetic peptide were assembled onto the surface of indium–tin oxide (ITO) electrodes by means of a layer-by-layer self-assembly technology. The as-obtained modified electrodes generated a lower photocurrent under irradiation due to the effect of EET. The photocurrent intensity increased due to the addition of type IV collagenase, which could specifically hydrolytically cleave Gly–Pro–Ala, leading to Ag NPs being away from the electrode surface. Thus, a signal-on PEC biosensor could be obtained. Under optimum conditions, the PEC biosensor for type IV collagenase exhibited a linear range from 0.5 to 50 μg mL−1 and sensitivity of 96 ng mL−1. The peptide-QD-based PEC detection against type IV collagenase showed a promising potential for other protease or kinase detection when we changed the substrate of the peptide.

Bifunctional heterogeneous catalytic processes for highly efficient removal of arsenic (As(iii)) are receiving increased attention. However, the agglomerated nature and stability of nanoparticles are major concerns. Herein, we report a new process regarding the anchoring of CuFe

A carbon aerogel composite templated and catalyzed by ionic liquid was fabricated to obtain a meso-porous and cross-linked structure while avoiding the freeze and supercritical drying. It was then carboxylated to obtain favorable surface groups. The easily prepared material displayed excellent extraction effect of six tetracyclines (TCs) compared to the non-carboxylated carbon aerogel. A direct immersion solid-phase microextraction method to determine six TCs in aqueous samples was developed coupling with high-performance liquid chromatography (HPLC) with UV-Vis detector set at 355 nm. The experimental parameters affecting the analytical performance of this method, including sample pH, ionic strength, extraction and desorption time, extraction volume, and temperature, were optimized. Adsorption kinetics and thermodynamics models were used to clarify the extraction mechanism. Under the optimized conditions, this method has a wide linear range of 2–1000 μg L−1, low limits of detection of 0.36–0.71 μg L−1, repeatability of 1.85–10.96%, and reproducibility of 4.92–13.47% for six TCs. The method was successfully applied to detect TC residues in egg and poultry farm wastewater samples.

Crystalline iron-based nanoparticles with spinel structure have received great attention for catalyzing peroxymonosulfate (PMS). This study introduces lead ferrite (PbFe2O4) as a novel, simple, and efficient catalyst to activate PMS for the degradation of organic contaminants in aqueous solution. The results indicated that, under pH 9.0, nearly 100% of 10 μM thionine was removed in 20 min. Operation factors, including pH, oxidant concentrations, catalyst dosage, and coexisting ions, were investigated and found to be influential for the thionine removal. PbFe2O4 showed higher catalytic activity and lower ions leaching than well-crystallized lead oxide (PbO) and ferric oxide (Fe2O3). The results from the characterization of the PbFe2O4 with X-ray diffraction (XRD) before and after reaction suggested that the structure and properties of the catalyst kept stable, and the recovered catalyst exhibited good catalytic performance during the recycling batch experiments. Free radical quenching experiments and electron paramagnetic resonance (EPR) spectra revealed that singlet-oxygen (1O2) is the dominant active oxygen species rather than sulfate radical for thionine degradation in PbFe2O4/PMS system. Meanwhile, the possible pathways of 1O2 generation were proposed: the redox reaction between Pb(Ⅳ)/Pb(II) and PMS may play an key role in PMS activation. This study provides an interesting insight in PMS activation by the high-efficient non-radical process, and the PbFe2O4 could be as efficient and recyclable heterogeneous catalyst for organic degradation.

The present study develops a rapid, simple and efficient method for the determination of type IV collagenase by using a specific peptide-modified quartz crystal microbalance (QCM). A small peptide (P1), contains a specific sequence (Pro-Gly) and a terminal cysteine, was synthetized and immobilized to the surface of QCM electrode via the reaction between Au and thiol of the cysteine. The peptide bond between proline and glycine can be specific hydrolyzed cleavage by type IV collagenase, which enabled the modified electrode with a high selectivity toward type IV collagenase. The cleaving process caused a frequency change of QCM to give a signal related to the concentration of type IV collagenase. The morphologies of the modified electrodes were characterized by scanning electron microscope (SEM) and the specific hydrolyzed cleavage process was monitored by QCM. When P1 was modified with gold nanoparticles (P1-Au NPs), the signal could be amplified to further enhance the sensitivity of the designed sensor due to the high-mass of the modified Au NPs. Compared the direct unamplified assay, the values obtained for the limit of detection for type IV collagenase was 0.96 ng mL-1, yielding about 6.5 times of magnitude improvement in sensitivity. This signal enhanced peptide based QCM biosensor for type IV collagenase also showed good selectivity and sensitivity in complex matrix.

In this study, magnesium/aluminum-layered double hydroxide (Mg/Al-LDH) was prepared with the hydrothermal method and the morphological features of Mg/Al-LDH were characterized. The as-prepared Mg/Al-LDH was employed as a coating material and coated on the stainless steel wire to construct a solid-phase microextraction fiber. To evaluate the extraction performance of the fiber, four phthalate esters including benzyl butyl phthalate, di-n-butyl phthalate, di-n-octyl phthalate and bis (2-ethylhexyl) phthalate were selected as model compounds. Several experimental parameters affecting the extraction efficiency, such as extraction temperature, extraction time and ionic strength, were optimized. Under the optimum conditions, linear ranges of 1–400 μg L−1 for di-n-butyl phthalate, 10–500 μg L−1 for di-n-octyl phthalate and 10–400 μg L−1 for two other compounds were observed. The limits of detection and limits of quantification ranged from 0.24 to 2.31 μg L−1 and 0.81 to 7.69 μg L−1, respectively. The intra-day and inter-day precision are less than 15.3 and 8.7%. The relative standard deviation of fiber to fiber reproducibility ranged from 8.3 to 16.7%. Finally, the established method was satisfactorily applied to the determination of phthalate esters in the Yangtze River water samples and the recoveries were 76.1–110.6%.

A signal-on photoelectrochemical (PEC) immunosensor was constructed for detecting tumor marker in this work. α-fetoprotein (AFP) was chosen as a model analyte to investigate the prepared procedure and the analytical performance of the exploited sensor. In order to construct the sensor, CdSe QDs were used as photoactive material, biotin conjugated AFP antibody (Bio-anti-AFP) as detecting probe, streptavidin (SA) as signal capturing unit, biotin functionalized apoferritin encapsulated ascorbic acid (Bio-APOAA) as amplification unit, which were assembled onto the electrodes. The sensing strategy was based on in situ enzymatic hydrolysis of Bio-APOAA to release ascorbic acid (AA) as sacrificial electron donor to produce photocurrent. The photocurrent from the immunosensor was monitored as a result of AFP concentrations. The constructed sensing platform displayed high selectivity and good sensitivity for detecting AFP. Under optimal conditions, a wide linear range from 0.001 to 1000 ng/mL and a low detection limit of 0.31 pg/mL were obtained. The developed immunosensor is expected to be used to determine AFP and other tumor markers in human plasma in clinical laboratories either for pre-cancer screening or cancer monitoring. Moreover, this sensing platform further has the potential to use for the detection of trypsin activity and the corresponding inhibitor-screening.

A signal-on photoelectrochemical (PEC) biosensor based on nano-encapsulant of ascorbic acid-loaded apoferritin-assisted for protease detection is described. The loaded ascorbic acid could be released from the central cavity of apoferritin into the buffer solution as sacrificial electron donor to capture the photo-generated holes of CdTe quantum dots when light is turned on. In this system, the biosensor relied on monitoring the photocurrent intensity as a result of enzymatic substrate proteolysis in the homogeneous aqueous solution. A low detection limit of 2.7ngmL-1 for trypsin in the linear range from 30 to 450ngmL-1 is achieved. We believe that such a sensing system not only holds the potential ability as a probe for trypsin activity assay, but also could be used for the corresponding inhibitor-screening. It might provide a potentially feasible alternative tool for determining trypsin in human serum in a clinical laboratory. The established method could open a different perspective for PEC enzyme detection and provide a new platform for future development of PEC analysis with other clinically important proteins.

A stainless steel wire coated with a polymeric ionic liquid (poly-IL) is shown to represent a viable new tool for solid-phase micro-extraction (SPME) of polychlorinated biphenyls (PCBs). The surface of the wire was covalently modified with 3-(trimethoxysilyl) propyl methacrylate, and susequent free-radical initiated polymerization of the ionic liquid (IL) 1-hexyl-3-vinylimidazolium bromide on the surface of the wire produced a poly-IL possessing sheet-like structure. The poly-IL fiber was evaluated with respect to its capability for extracting PCBs from water samples. The fiber aging temperature, extraction time, extraction temperature and ionic strength of the water sample were optimized. The poly-IL SPME fiber was applied to the headspace extraction of 12 kinds of PCBs (from PCB 81 to PCB 189) which, after direct injection into the port, were quantified by GC with ECD detection. The method displays good linearity in the 10 to 200 ng L−1 PCB concentration range, and limits of detection between 0.9 and 5.8 ng L−1. The single fiber and fiber-to-fiber repeatabilities are

To study the coagulation properties the refrigerated whole blood stored at 4℃.Ten units of whole blood were obtained from healthy volunteer donors and stored at 4±2℃ for 21 days. Samples were collected on the day after donation and on days 2, 4, 6, 8, 10, 14 and 21 for delection including complete blood count, electrolyte, APTT, PT, Fg, blood coagulation factors, and thromboelastography(TEG).The levels of Hb, WBC, Plt, sodium and potassium in each sample accorded with standard of storing whole blood. The level of Hb, WBC, Plt and NaThe whole blood stored for 10 days possesses normal coagulation function showing important significance for treatment of hemorrhage from war injury and surgical openation of heart and chest.

The prepared CuFe2O4 nanoparticles (NPs) resulting from a facile citrate–nitrate combustion method were adhesived on stainless steel wire with epoxy glue as a novel fiber coating. A direct immersion solid-phase microextraction (DI-SPME) method based on the prepared coating was established through sensitively detecting four phthalate esters (PAEs) from aqueous media with gas chromatography-flame ionization detection (GC-FID). The effects of various parameters on the efficiency of SPME process such as extraction time, extraction temperature, pH, ionic strength, desorption time, and desorption temperature were studied. Under optimized conditions, the limit of detections (LODs) and quantifications (LOQs) for the phthalate esters varied in the range of 0.12–0.40 μg·L−1 and 0.40–1.33 μg·L−1, respectively. The inter-day and intra-day relative standard deviations for these varied phthalate esters at 10 μg·L−1 concentration level (n = 6) using a single fiber were 3.9–12.4% and 6.6–15.1%, respectively. The fiber to fiber repeatabilities (n = 3), expressed as relative standard deviation (RSD%), were between 9.9% and 16.5% at 10 μg·L−1 concentration levell, and the the linear ranges varied between 1 and 500 μg·L−1. The prepared fiber can be repeatedly used to exceed 80 times, revealing a long lifetime and good stability. The method was successfully applied to analysis of the mineral water samples with recoveries from 81.1 to 103.7%. This work also provided an interesting insight for stable SPME fiber prepared by spinel materials for efficient extraction of PAEs.

A photoelectrochemical (PEC) sensor for determination of copper (II) ion has been developed. The indium tin oxide (ITO) electrode modified by ZnS quantum dots (QDs) was used as working electrode and dopamine (DA) as detection solution. When different amounts of Cu2+ were added, the polydopamine-copper (II) complex (PDA-Cu (II)) was in suit formed and attached tightly to the surface of ITO electrode based on the interaction between copper (II) and dopamine (DA) under weakly alkaline (pH 8.00) solution. The detection of Cu2+ was achieved by means of the decreasing photocurrent. The linear range of 1 - 1000 pM and sensitivity of 0.45 pM were obtained. In addition, the formation of PDA-Cu (II) was characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Thus, a PEC sensor based on the change of electrode surface state can realize the sensitive detection of Cu2+.

A rapid and facile route is followed to synthesize carbon dots (CDs) immobilized on the surface of steel wire from candle soot (CS) for the efficient and selective determination of phthalate esters (PAEs) as solid phase micro-extraction (SPME) coating. Five PAEs were selected as target analytes and detected through a head-space SPME mode coupling with gas chromatography-flame ionization detection (GC-FID) from aqueous samples. The effects of various factors on the extraction efficiency, such as extraction time, extraction temperature, salt content and stirring rate, were optimized through orthogonal experiment. Under the optimal conditions, the fiber showed a good linear in the concentration range of 1.0–500 μg·L−1 (R2 > 0.9909). The limit of detections (LODs) and quantifications (LOQs) ranged from 0.32 to 3.13 μg·L−1 and 1.07–10.43 for five PAEs, respectively. The relative standard deviation (RSD) of intra-day and inter-day for these PAEs at a concentration level of 10 μg·L−1 (n = 5) were 3.7–8.6% and 5.6–13.3%, respectively. The prepared fiber can be repeatedly used more than 50 times, showing a long lifetime and good stability. The proposed method had been successfully applied to the analysis of PAEs in real water samples with recoveries varied between 82 and 119%.

In this study, a facile route for the preparation of biochar coated fiber via dip method was built. The uniform biochar was produced by thermal decomposition of pine needles under limited or absence of oxygen. The robust adhesion of biochar to the etched stainless steel support was ensured by the viscosity of epoxy resin. The obtained fiber was utilized for headspace solid-phase micro-extraction (HS-SPME) of polychlorinated biphenyls (PCBs) from aqueous solution. The results of orthogonal experiment suggested that the maximum extraction efficiency for the target PCBs compounds was obtained when the extraction temperature, extraction time and the pyrolysis temperature of biochar were 60 °C, 30 min and 400 °C, respectively. Under the optimized conditions, the developed method showed good linearity between 40 and 320 ng L−1 with correlation coefficients (R) in the range of 0.9817–0.9936. The limits of detection (LOD) ranged from 12.3 to 24.3 ng L−1. The reproducibility for fiber-to-fiber obtained on two fibers was in the range of 9.5–20.4 %. The precisions for run-to-run found for 5 extraction times using one fiber in 1 day was less than 27.8 %. The relative standard deviations (RSD) for day-to-day achieved for 5 days was less than 22.4 %.

A novel coating material for solid-phase microextraction (SPME) was synthesized by treating magnesium/aluminum-layered double hydroxide (Mg/Al-LDH) with hydrogen peroxide in the presence of potassium iodide and was confirmed to be chemically and thermally stable. A direct immersion solid-phase microextraction method to determine phthalate esters (PAEs) in aqueous samples was developed using the constructed fiber coating to couple with gas chromatography. Several factors on SPME procedure were investigated in detail. Under the optimized conditions, the linear ranges of the developed method were between 1 and 500 μg L−1. The limits of detection and the limits of quantification for various phthalates were in the range of 0.42–1.29 μg L−1 and 1.40–4.13 μg L−1, respectively. The run-to-run RSD (n = 5) and the fiber-to-fiber RSD (n = 3) were 8.30–20.0% and 8.50–20.4%, respectively. This method was successfully applied to the analysis of PAEs from Yangtze River water samples and bottled mineral samples.

In this study, the iron oxide/silver (FexOy/Ag) nanocomposite has been successfully prepared by a facile one-step method using goethite (α-FeOOH) rods as support. The diameter of the as-synthesized goethite rods was between 250 and 500 nm and the silver nanoparticles sizes were about 10–50 nm. By varying the concentrations, the FexOy/Ag nanocomposite with different Ag contents are successfully obtained. The FexOy/Ag nanocomposite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy dispersive spectroscopy, respectively. Due to the unique nanostructure, these nanocomposites can catalyze degradation of both aromatic nitro compounds and organic dyes only within a few minutes, which show high catalytic performance.

A novel label-free strategy for the detection of bacteria was developed by using a specific antimicrobial peptide (AMP)-functionalized quartz crystal microbalance (QCM) electrode. This electrode interface was successfully applied to detect pathogenic Escherichia coli O157:H7 based on the specific affinity between the small synthetic antimicrobial peptide and the bacterial cell of pathogenic E. coli O157:H7. The concentrations of pathogenic E. coli O157:H7 were sensitively measured by the frequency response of the QCM with a detection limit of 0.4 cfu μL(-1). The detection can be fulfilled within 10 min because it does not require germiculture process. On the other hand, if the specific antimicrobial peptides were immobilized on a gold electrode, this label-free strategy can also be performed by electrochemical impedance spectroscopy (EIS). Compared with QCM technique, the EIS measurement gives a lower sensitivity and needs a longer assay time. The combination of antimicrobial peptides with the real-time responses of QCM, as well as electronic read-out monitoring of EIS, may open a new way for the direct detection of bacteria.

A uniform nickel oxide (NiO) nanoparticle decorated on carbon nanofibers (CNFs) hybrid with the assistance of ethylenediamine (EDA) following a simple on-spot pyrolysis route has been fabricated for insulin electrocatalytic oxidation. The fabricated hybrid displayed superior catalytic performance due to the synergetic effects between NiO nanoparticles and CNFs. Excellent analytical features, including high sensitivity (1.55 μA μM−1), short response time (

Binary Tb (III) complex with pyridine-2, 6-dicarboxylate (DPA) was synthesized by a simple process and its electrochemiluminesence (ECL) property in an aqueous solution was investigated carefully for the first time. Based on the ECL property of the synthesized Tb (III) complex, a new method to detect DPA with high sensitivity was established. Under the optimal condition, the linear relationship between enhanced ECL and the concentration of DPA was 2.0×10 −7 –3.4×10 −5 mol/L and the limit of detection (LOD) was 6.0×10 −8 mol/L. Furthermore, the possible mechanism for the ECL behavior of Tb (III) complex was also investigated.

A glassy carbon electrode was modified with β-manganese dioxide (β-MnO2), and glucose oxidase (GOx) was immobilized on its surface. The β-MnO2 nanowires were prepared by a hydrothermal method and characterized by scanning electron microscopy and powder X-ray diffraction. They were then dispersed in Nafion solution and cast on the glassy carbon electrode (GCE) to form an electrode modified with β-MnO2 nanowires that exhibits improved sensitivity toward hydrogen peroxide. If GOx is immobilized in the surface, the β-MnO2 acts as a mediator, and Nafion as a polymer backbone. The fabrication process was characterized by electrochemical impedance spectroscopy, and the sensor and its materials were characterized by cyclic voltammetry and amperometry. The biosensor enables amperometric detection of glucose with a sensitivity of 38.2 μA · mM−1 · cm−2, and a response time of < 5 s. This study also demonstrates the feasibility of realizing inexpensive, reliable, and high-performance biosensors using MnO2 nanowires.

A novel photoelectrochemical biosensor for step-by-step assay of tyrosinase and thrombin was fabricated based on the specific interactions between the designed peptide and the target enzymes. A peptide chain with a special sequence which contains a positively charged lysine-labeled terminal, tyrosine at the other end and a cleavage site recognized by thrombin between them was designed. The designed peptide can be fixed on surface of the CdTe quantum dots (QDs)-modified indium-tin oxide (ITO) electrode through electrostatic attraction to construct the photoelectrochemical biosensor. The tyrosinase target can catalyze the oxidization of tyrosine by oxygen into ortho-benzoquinone residues, which results in a decrease in the sensor photocurrent. Subsequently, the cleavage site could be recognized and cut off by another thrombin target, restoring the sensor photocurrent. The decrease or increase of photocurrent in the sensor enables us to assay tyrosinase and thrombin. Thus, the detection of tyrosinase and thrombin can be achieved in the linear range from 2.6 to 32 μg/mL and from 4.5 to 100 μg/mL with detection limits of 1.5 μg/mL and 1.9 μg/mL, respectively. Most importantly, this strategy shall allow us to detect different classes of enzymes simultaneously by designing various enzyme-specific peptide substrates.

A glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNTs) for electrochemical square-wave stripping voltammetric (SWV) determination of antimony (III) was introduced. Various experimental parameters, such as the amounts of carbon nanotubes, the deposition potential and time, the electrolyte solution, etc, were thoroughly optimized and discussed. Under the optimum experimental conditions, the MWCNTs-modified GCE exhibited well linear behaviour in the antimony(III) concentration range from 0.04 to 0.26 mg/L (R=0.9983) with a detection limit of 3.20×10-4 mg/L (S/N=3) under a 360 s accumulation. The proposed electrode also exhibited encouraging properties for measurements of simulated water samples.

Platinum nanoparticles were electrodeposited on graphene modified glassy carbon electrode to form a modified electrode, and the electrode was characterized with scanning electron microscopy (SEM). At the modified electrode, rutin, a natural flavonoid, shows a couple of well-defined redox peaks, which is corresponded to the reduction and reoxidation of rutin. The electrochemical behaviors of rutin at the electrode were investigated, and the results indicated that the electrode reaction is controlled by adsorption process. Under the optimal conditions, the peak currents of differential pulse voltammetry (DPV) increased linearly with the rutin concentration in the range from 2 . 0 × 1 0 − 8 to 8 . 0 × 1 0 − 5 M with a limit of detection of 6 . 7 × 1 0 − 9 M. The as-prepared electrode was successfully used for the selective determination of rutin in tablet, displaying a potential application of graphene composite modified electrode.

A new composite electrode has been prepared with doping graphene into the paste consisting graphite and ionic liquid, n-octyl-pyridinum hexafluorophosphate (OPFP). This electrode shows an excellent electrochemical activity for the redox of hydroquinone (HQ), catechol (CC), and resorcinol (RS). In comparison with bare paste electrode, the redox peaks of three isomers of dihydroxybenzene can be obviously, simultaneously observed at graphene doping paste electrode. Under the optimized condition, the simultaneous determination of HQ, CC, and RS in their ternary mixture can be carried out with a differential pulse voltammetric technique. The peak currents are linear to the concentration of HQ, CC, and RS in the range form 1 × 1 0 − 5 to 4 × 1 0 − 4 , 1 × 1 0 − 5 to 3 × 1 0 − 4 , and 1 × 1 0 − 6 to 1 . 7 × 1 0 − 4 mol L−1, respectively. The limits of detection are 1 . 8 × 1 0 − 6 mol L−1 for HQ, 7 . 4 × 1 0 − 7 mol L−1 for CC, and 3 . 6 × 1 0 − 7 M for RS, respectively.

We report on the sensitive determination of glucose using a glassy carbon electrode modified with CuO nanowires and a Nafion film. The structure and morphology of CuO nanowires were established by scanning electron microscopy and X-ray diffraction. The electrochemical performance of the modified electrode was investigated by cyclic voltammetry and chronoamperometry. Compared to a bare glassy carbon electrode, a substantial increase in efficiency of the electrocatalytic oxidation of glucose can be observed. The new glucose sensor displays two useful linear ranges of response towards glucose, is not affected by commonly interfering species, and displays a detection limit as small as 45 nM. The response time is

Electrochemiluminescence (ECL) behavior of quinoline in acetonitrile at a glassy carbon electrode was studied. Quinoline in 0.1 mol/L tetrabutylammonium bromide (TBAB) acetonitrile solution exhibited excellent ECL properties using conventional cyclic voltammetry (CV). One ECL peak was observed at −0.5 V. Effects of various factors were investigated. UV–visible absorption spectra measurements confirmed the production of new products after cycling the mixed solution. Fluorescence and ECL spectra measurements got the evidence that the luminophors were the products of quinoline. A possible mechanism process was proposed.

Nile Blue can strongly bind to DNA and its affinity for DNA has been investigated by spectroscopy and spectroelectrochemistry.At low DNA concentrations,Nile Blue can bind to DNA (per nucleotide phosphate) to form a 1:1 association complex with the binding constant of 4.7×10^4L／mol and the major binding model of Nile Blue to DNA is “electrostatic binding”.However,the major binding model changes into “intercalative binding ”at high DNA concentrations.In order to confirm which part of Nile Blue intercalating into DNA,the inclusion action of β-cyclodextric(β-CD) has been used to study the interation.Nile Blue can be included into the hydrophobic cavity of β-CD to form an inclusion complex with a stability constant of 1.9×10^3L／mol.The experimental results indicate that the naphthalene ring part of Nile Blue is included into β-CD′s hydrophobic cavity and the inclusion complex decomposes at high DNA concentrations.It may be deduced reasonably that the naphthalene ring part of Nile Blue molecule intercalates into DNA helix Strand.

Using porous cuprous oxide (Cu2O) microcubes, a simple non-enzymatic amperometric sensor for the detection of H2O2 and glucose has been fabricated. Cyclic voltammetry (CV) revealed that porous Cu2O microcubes exhibited a direct electrocatalytic activity for the reduction of H2O2 in phosphate buffer solution and the oxidation of glucose in an alkaline medium. The non-enzymatic amperometric sensor used in the detection of H2O2 with detection limit of 1.5 × 10−6 M over wide linear detection ranges up to 1.5 mM and with a high sensitivity of 50.6 μA/mM. This non-enzymatic voltammetric sensor was further utilized in detection of glucose with a detection limit of 8.0 × 10−7 M, a linear detection range up to 500 μM and with a sensitivity of −70.8 μA/mM. Keywords: Porous Cu2O microcubes, Non-enzymatic amperometric sensor, Hydrogen peroxide, Glucose