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A carrier gas mixture of nitrogen and helium has been employed to improve the resolving power at the expense of sensitivity for planar high-field asymmetric ion mobility spectrometry (FAIMS) in previous work. In this paper, a new hollow needle-to-ring ion source was developed, where the helium and nitrogen enter from the hollow needle and ring, respectively. It was found that the signal strengths of acetone, ethanol, and ethyl acetate increased by 8.5, 2.0, and 3.3 times for helium ratios of 20%, 20%, and 10%, respectively. At the same time, the absolute value of compensation voltage and the number of ion peaks increases. It shows that adding an appropriate helium ratio to nitrogen simultaneously improved the sensitivity and resolving power of planar FAIMS, which is reported for the first time.

Herein we report a label-free amperometric immunosensor based on reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) hybrid material co-modified by gold and iron-oxide magnetic nanoparticles (Au/MNPs-rGO-TEPA) for detection of carcinoembryonic antigen (CEA). The Au/MNPs-rGO-TEPA nanomaterials were prepared and coated on the working electrode as a sensing platform for antibody (anti-CEA) immobilization and signal amplification. This nanomaterial exhibited some excellent functionalities, such as magnetic and enhanced electrical properties due to its large specific surface area and favorable conductivity. Thionine (Thi) molecule was attached onto rGO-TEPA via π-π stacking and was used as an electrochemically active substance. The immunosensor was developed based on the increase in quantity of CEA captured, proportional to the decrease in peak currents of Thi. Under optimal conditions, the Au/MNPs-rGO-TEPA/Thi-based immunosensor showed impressive linear range from 0.1 pg/mL to 150 ng/mL. In addition, the proposed method had excellent linearity, high sensitivity, and relatively good stability, thereby offering a good platform for early clinical analysis.

A terahertz (THz) metamaterial biosensor is proposed to measure the thermal induced denaturation temperature of the insulin, a typical protein. The unit cell of the biosensor consists of a H-shaped metal structure enclosed by a U-shaped metal structure on a 500- $\mu \text{m}$ -thick high resistance silicon substrate. The metamaterial THz biosensor has high sensitivity of 85 GHz/RIU (Refractive Index Unit). The sample is fabricated using a surface micromachining process and characterized by a THz time-domain spectroscopy (TDS) system, using the insulin solution as analyte. Experimental results show that the sensor is very sensitive to the change of the insulin concentration, and the detectable concentration as low as 0.05 IU (Insulin Unit)/ $\mu \text{l}$ . In the experiment, three different concentrations of the insulin are used as the analytes and a temperature controllable heater is used to induce the denaturation of the insulin. The experimental results show that the denaturation starts from 70 °C and completes at about 88°C, and these two temperatures are independent of the initial concentrations of the insulin. The proposed biosensor has small size and high sensitivity, which are very useful for biological detection.

The abnormal content of hemoglobin in human body can lead to several diseases such as anemia, thalassemia, leukemia, heart disease. Therefore, it is very important for sensitive detection of hemoglobin in clinical analysis. An electrochemical approach is presented for detecting hemoglobin using disposable electrochemical sensors, which were based on the ability of the redox active ferrocene group of Fc[CO-Cys(Trt)-OMe]2 and Fc[CO-Glu-Cys-Gly-OH]. The two electroactive materials were adsorbed onto gold nanoparticles that were previously electrochemically deposited onto screen-printed electrodes. The as-prepared sensors were characterized by scanning electron microscopy and energy dispersive spectroscopy, and their electrochemical properties were characterized by cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy. Results indicated the Fc[CO-Glu-Cys-Gly-OH] prepared sensor showed enhanced current responses for hemoglobin catalysis than the Fc[CO-Cys(Trt)-OMe]2 prepared sensor. Optimal operating conditions were determined for hemoglobin detection by differential pulse voltammetry. The concentration of hemoglobin showed a good linear relationship with the current difference in the range of 0.1–1000 μg/mL and with 0.03 μg/mL limit of detection. The development of this electrochemical sensor was used for hemoglobin detection in human serum with a R.S.D. lower than 4.7% and recovery between 95.5% and 103.2%, which was in agreement with the data obtained from typical clinical analysis.

Bilirubin originates from hemoglobin metabolism and is an important biomarker for liver function. A ratiometric film sensor based on gold nanoclusters (AuNCs) was fabricated for highly sensitive determination of free bilirubin (fBR). Using bovine serum albumin (BSA) as a template, AuNCs that can emit blue and red fluorescence were prepared by the hydrothermal method at different pH values. Two kinds of AuNCs were incorporated into a single film by the layer-by-layer assembly (LBL) technique. The obtained thin-film showed dual fluorescence peaks excited at 372 nm, corresponding to the blue (443 nm) and red (622 nm) emissions of AuNCs respectively. When fBR interacted with the film, both fluorescence peaks were quenched at different degrees. A ratiometric method for fBR detection was established based on the fluorescence intensity ratio of the two emissions. The linear calibration curve for fBR lay in the concentration range of 0.01-2.00 μmol L-1 with a detection limit of 8.90 ± 0.34 nmol L-1 (S/N = 3). The film sensor showed a quick and sensitive response to fBR and could detect fBR in real samples with satisfactory results.

Using gold and magnetic nanoparticles co-decorated reduced graphene oxide-tetraethylenepentamine (rGO-TEPA/Au-MNPs) as the magnetic platform for capturing the primary antibody (Ab1), separation and preconcentration of immunocomplex, a novel homogeneous electrochemical immunosensor was successfully developed. The newly prepared magnetic rGO-TEPA/Au-MNPs, compared with MNPs, exhibited better stability and enhanced electrical conductivity attributed to rGO-TEPA, and showed higher biorecognition efficiency due to AuNPs. In addition, Au@PtNPs were prepared and modified with secondary antibody (Ab2) as an efficient signal probe for signal readout. Using carcinoembryonic antigen (CEA) as a model analyte, the prepared immunosensor demonstrated satisfactory properties like high stability, good repeatability and selectivity, wide linear range (5.0 pg mL−1~200.0 ng mL−1) as well as low detection limit (1.42 pg mL−1). The homogenous electrochemical immunosensor was applied to the detection of CEA in human serum and was found to exhibit good correlation with the reference method. Thus, the proposed rGO-TEPA/Au-MNPs-based homogenous immunoassay platform might open up a new way for biomarker diagnosis.

Sisal is a perennial tropical biomass with largest dosage in industry. Due to the special hard structure of sisal fiber, it can be prepared as carbon material and applied for negative material of lead-carbon battery. The pretreatment of sisal fiber was carried out by 5% NaOH and 5% H3PO4 and tested by the measurement of FTIR, thermogravimetric analysis and SEM. Carbazole was doped in pretreated sisal fiber to prepare carbon material by a simple approach with two-step method. The characterization of the synthesis doped-N carbon material was tested by Raman, BET, XRD and EDS. According to the result of BET, it was turned out that the doped-N carbon material had a larger specific surface area. And the electrochemical properties were measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Besides, the cycling life test and charge/discharge curve were performed on battery testing instrument. In addition, the lead-carbon battery contained doped-N carbon material had a longer discharge plateau and a higher ultimate capacity. It was concluded that doped-N carbon material had a better electrochemical performance compared to undoped-N carbon material.

In this paper, Newton's iterative method to solve the nonlinear matrix equation X+A∗X−nA=Q is studied. For the given initial matrix Q, the main results that the matrix sequence generated by the ite...

Two Metal-Organic Frameworks (MOFs) materials, namely, [Eu(bipy) (CH3COO) •H2O]n (1) and [Gd(bipy)(CH3COO)]n (2), had been synthesized and characterized by X-ray single crystal diffraction (XRD), i...

In the present research an attempt was made to develop and optimize rapamycin (Rapa) loaded hollow magnetic Fe3O4/graphene oxide (Fe3O4/GO) nanocomposites using solvent evaporation technique and response surface methodology (RSM). A Box-Behnken design (BBD) with a three-level, three-factor was used to determine preparation parameters that would achieve the highest encapsulation efficiency (EE) and drug loading capacity (DLC). At optimum conditions such as mass ratio of Rapa to Fe3O4/GO (Rapa: Fe3O4/GO) 0.45, oscillation rate 144.0, and volume ratio of water to solvent (W/S) 4.2, the EE and DLC of experimentally prepared particles reached 84.92 ± 5.50% and 28.68 ± 2.54% respectively. The morphological assessment results showed that hollow Fe3O4 nano-aggregates were evenly and tightly dispersed on the layer of GO membrane. After the addition of GO and encapsulation of Rapa, the Fe3O4/GO nanocomposites and Rapa loaded magnetic Fe3O4/GO (Fe3O4/GO-Rapa) nanocomposites showed saturation magnetization of 57.77 and 40.71 emu/g respectively. The drug releasing experiment indicated a slightly acidic atmosphere, which was suitable for Rapa releasing from the obtained Fe3O4/GO nanocomposites. The cell counting Kit-8 (CCK-8) assays demonstrated the hollow Fe3O4/GO nanocomposites could effectively improve the efficacy of Rapa in killing HepG2 cells, which displayed a concentration-dependent manner. All these results suggested the prepared Fe3O4/GO nanocomposites have a potential application in drug delivery system.

A novel, disposable and sensitive microfluidic paper-based electrochemical immunosensor (μ-PEI) was developed by using gold nanoparticles (Au NPs) decorated reduced graphene oxide-tetraethylene pentamine (rGO-TEPA/Au nanocomposite) as electrode materials. The rGO-TEPA greatly amplified the current response due to its excellent conductivity and large surface area. Au NPs was decorated on the surface of rGO-TEPA to increase the biocompatibility and retained good stability for rGO-TEPA/Au nanocomposite, which was used as an effective sensor platform for anchoring the capturing antibodies (Ab 1 ) and accelerating the electron transfer to the screen-printed electrodes (SPEs). The simple and disposable paper-based microfluidic channel patterned on the rGO-TEPA/Au nanocomposite modified SPEs (SPEs/rGO-TEPA/Au) was designed for combination of immunochromatography and immunofiltration simultaneously. With the combination of portable SPEs/rGO-TEPA/Au and simple paper-based microfluidic devices, horseradish peroxidase (HRP) and labeled signal antibodies (Ab 2 ) co-immobilized gold nanorods (HRP-GNRs-Ab 2 ) was explored as the tracers for square wave voltammetry (SWV) detection. Using Alpha-Fetoprotein (AFP) as a model analyte, the proposed μ-PEI exhibited a satisfactory performance like simple fabrication, high stability, selectivity, wide linear range (0.01 ng mL −1 –100.0 ng mL −1 ) with a low detection limit (0.005 ng mL −1 ). Furthermore, human serum were applied to the obtained μ-PEI and determined with satisfactory results.

An electrochemical immunofiltration analysis was introduced into microfluidic paper-based analytical devices (μPADs) for the first time, which was based on photolithography and screen-printing technology. The hydrophilic test zones of the aldehyde-functionalized screen-printed electrodes (SPEs) were biofunctionalized with capture antibodies (Ab1). A sensitive immune detection method was developed by using primary signal antibody functionalized gold nanoparticles (GNPs/Ab2) and alkaline phosphatase conjugated secondary antibody (ALP-IgG). Differential pulse voltammetry (DPV) was performed to detect the electrochemical response. The microfluidic paper-based electrochemical immunosensor (μ-PEI) was optimized and characterized for the detection of human chorionic gonadotropin (HCG), a model analyte, in a linear range from 1.0mIUmL-1 to 100.0 IU mL-1 with a detection limit of 0.36mIUmL-1. Additionally, the proposed μ-PEI was used to test HCG in real human serum and obtained satisfactory results. The disposable, efficient, sensitive and low-cost μ-PEI has exhibited great potential for the development of point-of-care testing (POCT) devices that can be applicated in healthcare monitoring.

Needle–cylinder electrodes designed to generate ionic wind have been explored experimentally. The increase of the gap distance between needle and cylinder from 4 mm to 16 mm cause an increase of the ionic wind velocity from 1.1 m/s to 2.46 m/s. The opposite behavior was observed when this distance lengthened from 18 to 28 mm. At the same time, a step voltage was used to increase the ionic wind velocity up to 3.6 m/s. These results indicate that electrode arrangement is very important to maximize the ionic wind velocity.

A needle-to-cylinder electrode, adopted as an ion source for high-field asymmetric ion mobility spectrometry (FAIMS), is designed and fabricated by lithographie, galvanoformung and abformung (LIGA) technology. The needle, with a tip diameter of 20 &mu, m and thickness of 20 &mu, m, and a cylinder, with a diameter of 400 &mu, m, were connected to the negative high voltage and ground, respectively. A negative corona and glow discharge were realized. For acetone with a density of 99.7 ppm, ethanol with a density of 300 ppm, and acetic ether with a density of 99.3 ppm, the sample gas was ionized by the needle-to-cylinder chip and the ions were detected by an LTQ XL&trade, (Thermo Scientific Corp.) mass spectrometer. The mass spectra show that the ions are mainly the protonated monomer, the proton bound dimer, and an ion-H2O molecule cluster. In tandem with a FAIMS system, the FAIMS spectra show that the resolving power increases with an increase in the RF voltage. The obtained experimental results showed that the micro needle-to-cylinder chip may serve as a miniature, low cost and non-radioactive ion source for FAIMS.

Serum bilirubin is an important biomarker for the diagnosis of various types of liver diseases and blood disorders. A polydopamine/gold nanoclusters composite film was fabricated for the fluorescent sensing of free bilirubin. Bovine serum albumin (BSA)-stabilized gold nanoclusters (AuNCs) were used as probes for biorecognition. The polydopamine film was utilized as an adhesion layer for immobilization of AuNCs. When the composite film was exposed to free bilirubin, due to the complex that was formed between BSA and free bilirubin, the fluorescence intensity of the composite film was gradually weakened as the bilirubin concentration increased. The fluorescence quenching ratio (F0/F) was linearly proportional to free bilirubin over the concentration range of 0.8~50 &mu, mol/L with a limit of detection of 0.61 &plusmn, 0.12 &mu, mol/L (S/N = 3). The response was quick, the film was recyclable, and common ingredients in human serum did not interfere with the detection of free bilirubin.

In this study, a sensitive and quantitative label-free electrochemical immunosensor based on bimetallic Au@Pt nanoparticles, Prussian blue (PB), and reduced graphene oxide-tetraethylene pentamine nanocomposite (rGO-TEPA) was constructed to achieve sensitive detection of HBsAg. A one-pot green method was used to synthesize interlocked rGO-TEPA/PB hybrid composites as high-performance materials with good conductivity. PB was the electron transfer mediator used to provide electrochemical signals. By utilizing rGO-TEPA as supporting material , the stability and intensity of PB were greatly improved. The incorporation of highly conductive Au@Pt nanoparticles could further amplify the electrochemical signal, and the high adsorption capacity could provide an efficient substrate for hepatitis B surface antibody (HBsAb) immobilization. Under optimal conditions, the immunoassay had a wide linear range from 0.25 pg mL−1 to 400 ng mL−1 and a low detection limit of 0.08 pg mL−1 (S/N = 3). This method was also applied to the analysis of human serum samples, and the obtained results were on par with those of electrochemiluminescence immunoassay (ECLIA), suggesting significant potential for this new method in clinical research.

The enhanced dissolution of Se without organo-phosphines is a key issue in the synthesis of oil-soluble selenide nanocrystals. In this article, the dissolution of Se powder was greatly promoted by addition of 1-dodecanethiol at 200–220 °C. This Se precursor was of high reactivity and was suitable for the preparation of Se semiconductor nanocrystals. With this greener Se precursor, approximately spherical and large-sized Mn:ZnSeS quantum dots (QDs) could be prepared after multiple injections of the Zn precursor, and the size of Mn:ZnSeS can reach over 8.5 nm after the tenth injection of the Zn precursor. The preparation of this novel selenium precursor is simple and convenient, and provides a meaningful method for the synthesis and application of other selenium nanocrystals.

Self-assembled monolayers (SAMs) of 4-((2-thiophenecarboxylic acid hydrazide) methylene) benzoic acid (HD2) (denoted as HD2-SAMs) were formed on copper surface. The SAMs were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. Polarization curve and weight loss methods indicated that the highest inhibition efficiency was 93.9% for CO 2 -saturated simulative oilfield water at a self-assembled time of 3 h. Potential-time curve, electrochemical impedance tests showed that HD2-SAMs on copper surface exhibited excellent inhibition effect at 30 °C. The adsorption behavior of HD2-SAMs on the copper surface followed the Langmuir adsorption isotherm, which was indicative of typically chemical adsorption. Quantum chemistry calculation showed that O and N atoms can interact with Cu atoms by coordination bonds which were the mainly active area of the adsorption of HD2 molecules.

Highly emissive semiconductor quantum dots (QDs) with tunable color are valuable in many applications such as solid state lighting and bio-imaging. Herein, we report a facile synthetic method to Au:ZnCdS and Au:ZnCdS/ZnS core/shell QDs with tunable emission color. The highly active Au precursor (HAuCl4) is prevented to be decomposed at high reaction temperature using 1-dodecanethiol (DDT) as the surface ligand. High-quality Au:ZnCdS/ZnS core/shell QDs are prepared and the highest photoluminescence (PL) quantum yield (QY) can achieve 42% by overcoating of ZnS layer over the bare Au:ZnCdS core QDs. Furthermore, through using Au+ ion as the primary dopants and trivalent cation In3+ as co-dopants, the PL QY can be enhanced significantly because compensation of In3+ ion-codoping for the charge imbalance from Au+-doping. This codoping strategy may be applied to other related optical materials to control the optical properties based on our understanding for physical mechanism.

Hepatitis B virus (HBV) DNA is an important biomarker for chronic HBV infection. To date, the majority of HBV biosensors have only focused on five basic factors (HBsAg, anti-HBs, HBeAg, anti-HBs, and anti-HBc), thus a sensitive, low-cost, and stable electrochemical sensor to measure the concentration of HBV-DNA remains needed. We present here a sensitive electrochemical DNA sensor that employs new nanoflower particles, gold nanoparticles, and two surface-immobilized aptamers to amplify the signal. The complex biosensor layers provide not only sufficient binding points, but also an adaptive framework for signal amplification and biocompatibility. The electrochemical DNA sensor exhibits a wide linear detection range from 1.10 × 103 to 1.21 × 105 copies/mL and a detection limit of 1100 copies/mL for HBV-DNA. The excellent performance in hepatitis B virus propagation detection suggests that the proposed electrochemical DNA sensor has great application potential in clinical diagnosis.

A needle-to-post ionization source was designed for high-field asymmetric waveform ion mobility spectrometry (FAIMS). The needle-to-post ion source includes asymmetric electrode comprised of a copper post with a diameter of 2 mm and a stainless-steel needle with 200-μm tip radius and length of 28 mm. With the discharge voltage of -5.6 kV and N2 gas flow, glow discharge was realized at atmospheric pressure. The mass spectra of ionized ions about acetone, ethanol and ethyl acetate were gotten by Thermo Scientific LTQ XL ion trap mass spectrometer (MS). The MS experimental results show that the main ions are protonated and dimer ions. The needle-to-post ion source was mounted on the FAIMS system and FAIMS spectra are gotten successfully. Separation of p-xylene, o-xylene and m-xylene was realized. It shows that the needle-to-post electrode could be used as the ion source in a FAIMS system.

Simple and facile electrochemical sensors for nitrite detection were fabricated by directly depositing ferrocenoyl cysteine conjugates Fc[CO-Cys(Trt)-OMe]2 [Fc(Cys)2] or Fc[CO-Glu-Cys-Gly-OH] [Fc-ECG] on screen-printed electrodes (SPEs). The modified carbon electrodes were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Results indicated that Fc-ECG/SPE sensor showed enhanced current response and a lower overpotential than Fc(Cys)2/SPE sensor for nitrite detection. Optimal operating conditions were estimated for nitrite detection by DPV. The concentration of nitrite showed a good linear relationship with the current response in the range of 1.0&ndash, 50 &mu, mol&middot, L&minus, 1 and with 0.3 &mu, 1 as the concentration for limit of detection. There were no interferences from most common ions. The development of this electrochemical sensor was used for nitrite detection in pickled juice with a R.S.D. lower than 2.1% and average recovery lower than 101.5%, which indicated that disposable electrochemical sensor system can be applied for rapid and precise nitrite detection in foods.

A headspace gas chromatographic method was developed for the determination of residual solvents in linezolid active substances. The solvents include petroleum ether (60–90°C), acetone, tetrahydrofuran, ethyl acetate, methanol, dichloromethane (DCM) and pyridine. The method showed the possibility to detect the tested solvents with a linear determination correlation coefficient (r) greater than 0.9995 except for petroleum ether (0.9980). The limits of detection ranged between 0.12 μg/mL (petroleum ether) and 3.56 μg/mL (DCM), and the limits of quantity ranged between 0.41 μg/mL (petroleum ether) and 11.86 μg/mL (DCM). The method achieved good accuracy (recoveries ranging from 92.8 to 102.5%) and precision for both run-to-run and day-to-day assay (relative standard deviation ranging from 0.4 to 1.3%) for all seven solvents concerned, which were applied in the quality control of three batches of linezolid successfully.

Yun Xing,1,2 Xiao-Zhen Feng,2 Lipeng Zhang,1 Jiating Hou,2 Guo-Cheng Han,2 Zhencheng Chen2 1Henan Province of Key Laboratory of New Optoelectronic Functional Materials, College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, 2School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi, People’s Republic of China Abstract: Soluble beta-amyloid (Aβ) oligomer is believed to be the most important toxic species in the brain of Alzheimer’s disease (AD) patients. Thus, it is critical to develop a simple method for the selective detection of Aβ oligomer with low cost and high sensitivity. In this paper, we report an electrochemical method for the detection of Aβ oligomer with a peptide as the bioreceptor and silver nanoparticle (AgNP) aggregates as the redox reporters. This strategy is based on the conversion of AgNP-based colorimetric assay into electrochemical analysis. Specifically, the peptide immobilized on the electrode surface and presented in solution triggered together the in situ formation of AgNP aggregates, which produced a well-defined electrochemical signal. However, the specific binding of Aβ oligomer to the immobilized peptide prevented the in situ assembly of AgNPs. As a result, a poor electrochemical signal was observed. The detection limit of the method was found to be 6pM. Furthermore, the amenability of this method for the analysis of Aβ oligomer in serum and artificial cerebrospinal fluid (aCSF) samples was demonstrated. Keywords: electrochemical biosensors, Alzheimer’s disease, beta-amyloid oligomer, peptide, silver nanoparticles

We designed and fabricated a new micro-needle-column discharge chip by Lithographie, Galvanoformung and Abformung technology to meet sterilization requirements. The dimensions of the chip are 11.6 mm × 11.7 mm × 3 mm. The micro-discharge structure is composed of a needle electrode and two cylinder electrodes. We employed a needle with a tip diameter of 20 [Formula: see text]m and a thickness of 20 [Formula: see text]m as the discharge cathode. We used a cylinder with a thickness of 1 mm and diameter of 0.4 mm as the anode. We carried out the gas discharge experiments in ambient air and at room temperature, without external air flow. In the experiments, a corona and glow discharge with applied voltages of −2.1 kV and −3.8 kV were realized. We carried out the sterilization experiments for six different discharge times (15, 30, 60, 90, 120 and 180 s) with an applied voltage of −3.8 kV. The inactivation efficiency of Escherichia coli and Staphylococcus aureus reached 100% for sterilization times of 120 s and 180 s. This indicates that the micro-needle-column discharge chip may be suitable as a portable sterilizer.

The injection and ionization of volatile organic compounds (VOA) by an integrated chip is experimentally analyzed in this paper. The integrated chip consists of a needle-to-cylinder electrode mounting on the Polymethyl Methacrylate (PMMA) substrate. The needle-to-cylinder electrode is designed and fabricated by Lithographie, Galvanoformung and Abformung (LIGA) technology. In this paper, the needle is connected to a negative power supply of −5 kV and used as the cathode; the cylinder electrodes are composed of two arrays of cylinders and serve as the anode. The ionic wind is produced based on corona and glow discharges of needle-to-cylinder electrodes. The experimental setup is designed to observe the properties of the needle-to-cylinder discharge and prove its functions as an ion source and air pump. In summary, the main results are as follows: (1) the ionic wind velocity produced by the chip is about 0.79 m/s at an applied voltage of −3300 V; (2) acetic acid and ammonia water can be injected through the chip, which is proved by pH test paper; and (3) the current measured by a Faraday cup is about 10 pA for acetic acid and ammonia with an applied voltage of −3185 V. The integrated chip is promising for portable analytical instruments, such as ion mobility spectrometry (IMS), field asymmetric ion mobility spectrometry (FAIMS), and mass spectrometry (MS).

The work focused on manufacturing improved drug loaded multifunctional magnetic nanoparticles that can overcome the relative non-specificity and potential side-effects of some chemotherapeutic drugs to healthy tissues. A new drug delivery system, Chelerythrine (CHE) and Fe3O4 loaded multi-walled carbon nanotubes (Fe3O4/MWNTs-CHE nanocomposites) that can target hepatocytes when treating malignant tumors, was prepared through a simple adsorption method. The formulation and structure of the Fe3O4/MWNTs-CHE nanocomposites were characterized by vibrating sample magnetometer (VSM), Fourier Transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The cytotoxicity and anti-proliferation effect from the prepared nanocomposites were in vitro tested on human hepatocarcinoma HepG2 and normal liver LO2 cell lines. The results showed the saturated magnetization of Fe3O4/MWNTs-CHE nanocomposites could reach to 45.4O3 emu/g, and the in vitro CHE release behavior exhibited a biphasic release pattern. Moreover, the in vitro cytotoxicity studies revealed that the Fe3O4/MWNTs-CHE nanocomposites showed an efficient inhibition rate to HepG2 cell line and exhibited a lower cytotoxicity to LO2 cell line in comparison to the native CHE. Therefore, the multifunctional Fe3O4/MWNTs-CHE nanocomposites should be a useful and promising candidate for treatment of malignant tumors.

A new needle-to-droplet electrode structure with a micro discharge gap (2 mm) was designed to achieve direct current (DC) discharge plasma in ambient air with the aim of using the plasma to sterilize liquids. Without using noble gases or an external air flow, we succeeded in generating both a negative and positive DC plasma at atmospheric pressure. The plasma was driven by a 0 to −20,000 V, 100 W DC power supply. A stainless steel needle with a tip diameter of [Formula: see text] and a 200-[Formula: see text] droplet of bacteria-containing liquid served as the electrodes. At atmospheric pressure and room temperature (23[Formula: see text]C), utilizing the negative DC plasma, the discharge time lasted 10 s; the results showed that the higher the discharge voltage, the more efficient the sterilization effect. Conversely, when we applied a voltage of −5.5 kV, we found that the sterilization effect was more efficient for longer discharge times. Our findings demonstrate that Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) can be killed in about 30 s. Our experiments show that our sterilization method required less time and was more efficient for positive than for negative DC plasma under the same conditions.

A needle-to-cylinder electrode configuration was proposed to generate an ionic wind at atmospheric pressure. Experiments were conducted with negative voltage ranging from 0 to −20 000 V at atmospheric pressure and room temperature. Negative corona, glow, and arc discharges in ambient air were achieved without external airflow, as confirmed by some typical characteristics of their discharge waveforms and images. The experiments indicate that: (1) the discharge current in a glow discharge is larger than that in a corona discharge; (2) the ionic wind velocity does not increase monotonically with increasing discharge current; and (3) the ionic wind velocity increases with increasing voltage in the corona discharge phase, while decreasing in the glow discharge phase. A detailed study was conducted on why varying behaviors occur for these different types of air discharges and how they affect electrohydrodynamic flow. The results help in establishing a guide for electrohydrodynamic design.