Establishment of a fabrication method for a long-term actuated hybrid cell robot

We developed a novel method to fabricate a crab-like microrobot that can actuate for a long period in a physiological condition. The microrobot backbone was built with a biocompatible and elastic material-polydimethylsiloxane (PDMS)-by using a specially designed 3D molding aligner, and consisted of three strips of PDMS "legs" connected across a "body." Cardiomyocytes were then plated on the grooved top surface of the backbone, resulting in a high concentration of pulsating cells. These key techniques enabled the microrobot to walk continuously for over ten days. The performance of our crab-like microrobot was measured at an average velocity of 100 microm s(-1), and the estimated total distance it travelled was 50 m over a one-week period. Thus, we have demonstrated for the first time a walking robot that exhibited reliable and long-term actuation performances.     

Synthesis and characterization of magnetic nanocomposite for in vitro evaluation of irinotecan using human cell lines

In this study, magnetic O-carboxymethyl chitosan (MOCC) nanocomposite was synthesized and characterized as a drug delivery system for loading the anticancer drug irinotecan (CPT-11). To increase the drug loading capacity, MOCC was synthesized by linking the carboxyl group functionally to chitosan. Also, several critical factors such as concentration, the dose of MOCC, and contact time for optimum drug loading condition were investigated. The loading capacity of CPT-11 onto MOCC was calculated as 5.6 mg/g, and the loaded drug concentration was calculated as 0.04787 mM at pH value of 5. Besides, the cytotoxic properties of MOCC, CPT- 11 loaded MOCC (MOCC-CPT-11), and free CPT-11 were studied on glioblastoma multiforme cell lines, including U87 and U373. According to the results, the MOCC-CPT-11 showed at least as toxic effect as free CPT-11 even at very low concentrations, while the MOCC showed slight toxicity (cell viability of 96% to 78%) on U373 cell lines at all concentrations and for 24 h and 48 h incubation times. Moreover, the results showed that the MOCC indicated significant toxicity in increasing concentrations and incubation times, and the MOCC-CPT-11 is as toxic as free CPT-11 on U87 cells at all concentrations and incubation times.     

Preparation, characterization and application of magnetic silica nanoparticle functionalized multi-walled carbon nanotubes

Magnetic silica nanoparticle functionalized multi-walled carbon nanotubes (MS-MWNTs) were prepared, characterized and used for the convenient, rapid and efficient separation of trace aromatic compounds.     

Soliton solutions for time fractional coupled modified KdV equations using new coupled fractional reduced differential transform method

In this paper, new Coupled Fractional Reduced Differential Transform has been implemented to obtain the soliton solutions of coupled time fractional modified KdV equations. This new method has been revealed by the author. The fractional derivatives are described in the Caputo sense. By using the present method, we can solve many linear and nonlinear coupled fractional differential equations. The results reveal that the proposed method is very effective and simple for obtaining approximate solutions of fractional coupled modified KdV equations. Numerical solutions are presented graphically to show the reliability and efficiency of the method. Solutions obtained by this new method have been also compared with Adomian decomposition method (ADM).     

Preparation and characterization of aqueous polyaniline battery using a modified polyaniline electrode

A rechargeable battery of the type Zn/ZnCl₂, NH₄Cl/polyaniline (PAn)-reticulated vitreous carbon was successfully prepared based on a PAn modified electrode. Voltage of the battery was 1.2 V. Charge-discharge behavior at a constant load of 2.5 k, recycle ability and the rate of self-discharge were measured. The results showed that the battery has a capacity of 121 mA h g⁻¹ polymer weight and coulombic efficiency was in the range between 75% and 100%. Self-discharge rate was less than 1% per day and the battery showed a good recycle ability. It was also found that even after 70 cycles, the decrease in the open-circuit voltage was less than 5%.     

Resonance Rayleigh scattering spectral method for the determination of raloxifene using gold nanoparticle as a probe

When gold nanoparticles were being prepared by sodium citrate reduction method, citrate anions self-assembled on the surface of gold nanoparticles to form supermolecular complex anions with negative charges, and protonated raloxifene (Ralo) was positively charged and could bind with the complex anions to form larger aggregates through electrostatic force and hydrophobic effects, which could result in the remarkable enhancement of the resonance Rayleigh scattering intensity (RRS), and the appearance of new RRS spectra. At the same time, the second-order scattering (SOS) and frequency-doubling scattering (FDS) intensities were also enhanced. The maximum wavelengths were located near 370 nm for RRS, 520 nm for SOS, and 350 nm for FDS, respectively. Among them, the RRS method had the highest sensitivity and the detection limit was 5.60 ng mL⁻¹ for Ralo, and its linear range was 0.05-2.37 μg mL⁻¹. A new RRS method for the determination of trace Ralo using gold nanoparticles probe was developed. The optimum conditions of the reaction and influencing factors were investigated. In addition, the reaction mechanism and the reasons for the enhancement of RRS were discussed.     

Synthesis of modified uracil and cytosine nucleobases using a microwave-assisted method

Modified nucleobases and nucleic acids have found many biological and pharmaceutical applications. Here we report a microwave-directed synthesis of a variety of modified uracil and cytosine nucleobases with high yields under solvent-free conditions. The reaction yields were further improved by addition of Lewis acid. The crystal structures of 5-isopropyl-6-methyluracil and 6-phenyluracil were also determined.     

Colorimetric detection of pathogenic bacteria using platinum-coated magnetic nanoparticle clusters and magnetophoretic chromatography

A colorimetric method that uses platinum-coated magnetic nanoparticle clusters (Pt/MNCs) and magnetophoretic chromatography is developed to detect pathogenic bacteria. Half-fragments of monoclonal Escherichia coli O157:H7 (EC) antibodies were functionalized to Pt/MNCs and used to capture E. coli bacteria in milk. After magnetic separation of free Pt/MNCs and Pt/MNC-EC complexes from the milk, a precision pipette was used to imbibe the E. coli-containing solution, then a viscous polyethylene glycol solution. Due to difference in viscosities, the solutions separate into two liquid layers inside the pipette tip. The Pt/MNC-EC complexes were separated from the free Pt/MNCs by applying an external magnetic field, then added to a tetramethylbenzidine (TMB) solution. Catalytic oxidation of TMB by Pt produced color changes of the solution, which enabled identification of the presence of 10 cfu mL⁻¹E. coli bacteria with the naked eye. The total assay time including separation, binding and detection was 30 min.     

Demonstration of a magnetic and catalytic Co@Pt nanoparticle as a dual-function nanoplatform

Co@Pt nanoparticles as a bifunctional nanoplatform system for the hydrogenation of various unsaturated organic molecules under mild conditions and also for magnetic separation and recycling are demonstrated.     

Silica coating of silver nanoparticles using a modified Stober method

Silver nanoparticles prepared through a borohydride-reduction method were directly coated with silica by means of a seeded polymerization technique based on the Stober method. Various amine catalysts were used for initialization of a sol-gel reaction of TEOS with no need for a prior surface modification. Use of dimethylamine (DMA) as a catalyst was found to be necessary to obtain a proper coating. The silica shell thickness was varied from 28 to 76 nm for TEOS concentrations of 1-15 mM at 11.1 M water and 0.8 M DMA. The optical spectra of the core-shell silver-silica composite particles show a qualitative agreement with predictions by Mie theory.     

A highly efficient and versatile microchip capillary electrophoresis method for DNA separation using gold nanoparticle as a tag

A highly efficient and versatile method for DNA separation using Au nanoparticles (Au NPs) as a tag based on microchip capillary electrophoresis (MCE) was developed. The thiol-modified DNA-binding Au NPs were utilized as a tag. Target DNA was sandwiched between Au NPs and probe DNA labeled with horseradish peroxidase (HRP). In electrophoresis separation, the difference in electrophoretic mobility between free probe and probe-target complex was magnified by Au NPs, which enabled the resulting mixture to be separated with high efficiency by microchip capillary electrophoresis. Horseradish peroxidase was used as a catalytic label to achieve sensitive electrochemical DNA detection via fast catalytic reactions. With this protocol, 27-mer DNA fragments with different sequences were separated with high speed and high resolution. The proposed method was critical to achieve improved DNA separations in hybridization analyses.     

螺旋霉素分子印迹磁性纳米吸附剂的合成及应用

制备了一种以螺旋霉素为模板分子的分子印迹磁性纳米吸附剂。以磁性纳米Fe₃O₄为内核,经丙烯酸表面修饰后再以螺旋霉素为模板分子、甲基丙烯酸为功能单体、乙二醇二甲基丙烯酸酯为交联剂,通过表面自由基聚合反应制备得到。该吸附剂对螺旋霉素、交沙霉素、替米考星和酒石酸泰乐菌素4种大环内酯类抗生素表现出良好的富集效果（富集倍数分别为310、118、758和72）,其选择性明显优于常规C₁₈吸附剂。该吸附剂可重复使用至少6次。结合高效液相色谱-紫外检测器建立了上述4种抗生素的分析方法。方法检出限为0.53~2.75 μg/L,定量限为1.78~9.16 μg/L;在50、100和150 μg/L低中高3个添加水平下,方法回收率在80.78%~123.02%之间,相对标准偏差<15.8%（n=5）。该方法被应用于分析蜂蜜中的上述4种抗生素。     

Synthesis and characterization of magnetic nano-material for removal of Eu3+ ions from aqueous solutions

Ferrite coated apatite magnetic nano-material was synthesized by a co-precipitation method and applied in removal of Eu(III) ions from aqueous solutions. The sample was firstly characterized using Fourier transform infrared spectroscopy, thermogravimetric analyses, deferential thermal analysis, X-ray powder diffraction, surface area by nitrogen adsorption and scanning electron microscopy. The results of physicochemical properties indicated that the synthesized magnetic nano-adsorbent had a crystalline structure and possessed a surface area amounted to 85.11 m² g^?1. Further, it was found to have high thermal resistance up to 600 °C and mean particle size of about 63 nm. The kinetic of Eu(III) sorption indicated that equilibrium state was attained within 12 h with using 5 mg as an appropriate nano-adsorbent weight. The sorption process was pH and ionic strength dependent. The maximum adsorbed amount of Eu(III) was attained at pH 2.5 with value reached to 157.14 mg g^?1. Desorption of Eu(III) from loaded samples was studied using various eluents and maximum recovery was obtained using FeCl₃ solution.     

On the calculation of activation energies using a modified Kissinger method

Augis and Bennett (J. Thermal Anal. 13 (1978) 283.) [6] recently proposed a modified Kissinger method for determining the activation energy of a transformation. It is shown that the proposed method was, in fact, based upon a modification to the equation for the rate of reaction under non-isothermal conditions. The apparent discrepancy between the proposed method and the original Kissinger method is therefore resolved. The modified rate equation appears to have, at best, only a limited application. However, if the equation should be appropriate for a particular transformation, it is demonstrated that Augis and Bennett's method would be the correct method for determining the activation energy.

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Zusammenfassung Von Augis und Bennett (J. Thermal Anal.13, (1978) 283) wurde eine modifizierte Kissinger-Methode zur Bestimmung der Aktivierungsenergie einer Umwandlung vorgeschlagen. Es wird gezeigt, dass die vorgeschlagene Methode tatsächlich in einer Modifizierung der Gleichung für die Reaktionsgeschwindigkeit unter nicht-isothermen Bedingungen ihren Ursprung hat. Die scheinbare Diskrepanz zwischen der vorgeschlagenen Methode und der ursprünglichen Kissinger-Methode wird dadurch behoben. Die modifizierte Geschwindigkeitsgleichung hat bestenfalls nur eine begrenzte Anwendung. Jedoch, bei Eignung dieser Gleichung für eine bestimmte Umwandlung zeigt sich, dass die Methode von Augis und Bennett die richtige Methode zur Bestimmung der Aktivierungsenergie sein kann.

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(J. Thermal Anal. 13 (1978) 283.) - . , , , . , . , , , . , , .

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The author is indebted to the Senate of the University of Queensland for the award of a University Research Fellowship; and to Professor R. R. Stephens for providing laboratory facilities.     

Synthesis and characterization of a Ni nanoparticle stabilized on Ionic liquid‐functionalized magnetic Silica nanoparticles for tandem oxidative reaction of primary alcohols

In this research, preparation of the magnetic nanoparticle, coating by a silica shell using (3‐aminopropyl) triethoxysilane and synthesis of a novel sulfonic acid‐substituted imidazolium‐based ionic liquid onto the surface of these particles via a multi‐component reaction, is described. The functionalized nanoparticles was loaded by Ni nanoparticles and characterized by means of techniques such as XRD, FTIR, SEM, EDX, TEM, TGA and ICP‐OES. The nanostructures have spherical shapes that ranged in size from 80 to 100 nm. The catalytic activity of these nanoparticles was tested in aerobic oxidation of primary alcohols that showed good performance in the wide range of primary alcohols in water at mild reaction conditions. As a second step of this work, the tandem oxidative synthesis of alkylacrylonitriles and bisindolylmethanes were investigated using primary alcohols under oxidation conditions. This catalyst system can be recovered using external magnet and reused for five consecutive cycles without significantly less of its activity.     

Determination of thiabendazole in aqueous solutions using a cucurbituril-enhanced fluorescence method

The complexation of thiabendazole (TBZ) with the cucurbit[6]uril (Q[6]), cucurbit[7]uril (Q[7]) and symmetric tetramethyl-cucurbit[6]uril (TMeQ[6]) in aqueous solution has been investigated using UV–vis and fluorespectrometry. The experimental results show 1:1 host–guest inclusion complexes at pH 6.5 for all three macrocyclic hosts, and the corresponding formation constants by UV and fluorescence methods are (5.37?±?1.05)?×?10⁴?L?mol^?1 and (1.47?±?0.41)?×?10⁴?L?mol^?1 for the Q[6]-TBZ system (7.76?±?0.51)?×?10⁴?L?mol^?1 and (9.36?±?0.22)?×?10⁴?L?mol^?1 for the Q[7]-TBZ system (1.28?±?0.78)?×?10⁴?L?mol^?1 and (2.69?±?0.55)?×?10⁴?L?mol^?1 for the TMeQ[6]-TBZ system, respectively. Based on the enhancement of the fluorescence intensity of TBZ with the addition of Q[n]s in neutral media, a fluorespectrometry method for the determination of TBZ in aqueous solution in the presence of Q[n] was established. In the range of 6.0?×?10^?8?mol?L^?1–8.0?×?10^?6?mol?L^?1 a linear relationship was obtained between fluorescence intensity and TBZ concentration. The detection limit was found to be between 5.51 and 8.85?×?10^?9?mol?L^?1. The interference of coexisting ions was found to be slight. The proposed method has been successfully applied to the determination of TBZ in different aqueous solutions with satisfactory recoveries of 92–103%. The method seems to be suitable for environmental water analysis.     

Nickel nanoparticles obtained by a modified polyol process: synthesis, characterization, and magnetic properties

The synthesis of nickel nanoparticles using poly(N-vinilpyrrolidone) (PVP) as protective agent was studied. The nanoparticles were prepared in air according to a modified polyol route, using nickel chloride as precursor and sodium borohydride as reducing agent. Samples with different nickel/PVP ratio were obtained. The X-ray diffraction and transmission electron microscopy (TEM) measurements indicate the occurrence of face-centered cubic metallic nickel nanoparticles with a medium diameter of 3.8 nm and good size dispersion. Fourier transformed infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) data show an effective interaction between the nickel nanoparticles surface and the carboxyl oxygen atoms of PVP. Magnetic measurements show single-domain nonideal superparamagnetism behavior due to dipolar magnetic coupling between particles.     

A facile and sensitive immunoassay for the detection of alpha-fetoprotein using gold-coated magnetic nanoparticle clusters and dynamic light scattering

A facile and sensitive immunoassay protocol for the detection of alpha-fetoprotein (AFP) was developed using gold-coated iron oxide magnetic nanoclusters and dynamic light scattering (DLS) methods. The increase in the average particle size due to AFP-mediated aggregation was measured using DLS, and the detection limit was better than 0.01 ng mL(-1).