Direct synthesis of graphene-chitosan composite and its application as an enzymeless methyl parathion sensor.

This paper proposed a direct electrodeposition approach to synthesis of graphene-chitosan (GR-CS) composite onto glassy carbon electrode (GCE) under controlled potential. This direct electrodeposition approach for the construction of GR-based hybrid was environmentally friendly, which would not involve the chemical reduction of graphene oxide (GO) and therefore result in no further contamination. The whole procedure was simply and cost only several minutes.

Application of multi-walled carbon nanotubes modified carbon ionic liquid electrode for electrocatalytic oxidation of dopamine.

A simple, sensitive, and reliable method based on a multi-walled carbon nanotubes (MWNTs) modified carbon ionic liquid electrode (CILE) has been successfully developed for determination of dopamine (DA) in the presence of ascorbic acid (AA). The acid-treated MWNTs with carboxylic acid functional groups could promote the electron-transfer reaction of DA and inhibit the voltammetric response of AA. Due to the good performance of the ionic liquid, the electrochemical response of DA on the MWNTs/CILE was better than that of other MWNTs modified electrodes.

Bioremediation of heavy metals by growing hyperaccumulaor endophytic bacterium Bacillus sp. L14.

Heavy metal bioremediation by a multi-metal resistant endophytic bacteria L14 (EB L14) isolated from the cadmium hyperaccumulator Solanum nigrum L. was characterized for its potential application in metal treatment. 16S rDNA analysis revealed that this endophyte belonged to Bacillus sp.

Amperometric glucose biosensor with remarkable acid stability based on glucose oxidase entrapped in colloidal gold-modified carbon ionic liquid electrode.

A colloidal gold-modified carbon ionic liquid electrode was constructed by mixing colloidal gold-modified graphite powder with a solid room temperature ionic liquid n-octyl-pyridinium hexafluorophosphate (OPPF(6)). Glucose oxidase (GOD) was entrapped in this composite matrix and maintained its bioactivity well and displayed excellent stability. The effect conditions of pH, applied potential and GOD loading were examined.

Fabrication of DNA functionalized carbon nanotubes/Cu(2+) complex by one-step electrodeposition and its sensitive determination of nitrite.

In this paper, DNA functionalized single-wall carbon nanotubes/Cu(2+) (DNA-CNTs/Cu(2+)) complex was one-step electrodeposited onto the glassy carbon electrode (GCE), which fabricated a DNA-CNTs/Cu(2+)/GCE sensor to detect nitrite. Cyclic voltammogram of DNA-CNTs/Cu(2+)/GCE showed a pair of well-defined redox peaks for Cu(2+)/Cu(+). Compared with DNA-CNTs/GCE and DNA-Cu(2+)/GCE, the prepared DNA-CNTs/Cu(2+)/GCE exhibited more excellent electrochemical properties.

Direct electrochemistry and electrocatalytic properties of hemoglobin immobilized on a carbon ionic liquid electrode modified with mesoporous molecular sieve MCM-41.

The direct electron transfer and electrocatalysis of hemoglobin (Hb) entrapped in the MCM-41 modified carbon ionic liquid electrode (CILE) were investigated by using cyclic voltammetry in 0.10 M pH 7.0 phosphate buffer solution (PBS).

[Separation and identification of 5 glycosidic flavor precursors in tobacco by ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry].

A qualitative method for the identification of 5 main glycosidic flavor precursors in tobacco was developed by using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI MS/MS) and gas chromatography-mass spectrometry (GC-MS). The glycosidic flavor precursors in tobacco were extracted with methanol, cleaned up with an XAD-2 column. The aglycones were later released by enzyme-mediated hydrolysis under the condition of pH 5.

Biosorption of cadmium by endophytic fungus (EF) Microsphaeropsis sp. LSE10 isolated from cadmium hyperaccumulator Solanum nigrum L.

A novel technology to obtain highly efficient biosorbent from the endophytes of a hyperaccumulator is reported. This technology is more convenient than the traditional method of obtaining biosorbents by experimentally screening many types of biomass by trial and error. Using this technology, endophytic fungus (EF) LSE10 was isolated from the cadmium hyperaccumulator Solanum nigrum L.

A third-generation hydrogen peroxide biosensor based on horseradish peroxidase immobilized on DNA functionalized carbon nanotubes.

In this paper, DNA functionalized SWCNTs were used to immobilize horseradish peroxidase (HRP) on glassy carbon (GC) electrode. Cyclic voltammetry showed that the direct electrochemistry of HRP immobilized on DNA-SWCNTs hybrids was achieved. The DNA interlayer between the SWCNTs and HRP could be used to keep the activity of HRP.

Kinetic study and mathematical modeling of chromium(VI) reduction and microorganism growth under mixed culture.

The kinetics of chromium(VI) reduction by Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli) was studied under both pure and mixed cultures.

Electrodeposition of chitosan-ionic liquid-glucose oxidase biocomposite onto nano-gold electrode for amperometric glucose sensing.

A sensitive glucose biosensor was fabricated by electrodepositing chitosan-ionic liquid-glucose oxidase biocomposite onto nano-gold electrode. First, nano-gold electrode was constructed by electrochemically depositing gold nanoparticles onto a flat gold electrode surface. Then the nano-gold electrode was immersed in the bath containing p-benzoquinone (BQ), chitosan (CS), glucose oxidase (GOD) and ionic liquid (IL) for electrodeposition of enzymatic electrode.

Kinetic and equilibrium studies for the adsorption process of cadmium(II) and copper(II) onto Pseudomonas aeruginosa using square wave anodic stripping voltammetry method.

A novel method for the simultaneous determination of cadmium(II) and copper(II) during the adsorption process onto Pseudomonas aeruginosa was developed. The concentration of the free metal ions was successfully detected by square wave anodic stripping voltammetry (SWASV) on the mercaptoethane sulfonate (MES) modified gold electrode, while the P. aeruginosa was efficiently avoided approaching to the electrode surface by the MES monolayer.

Layer-by-layer assembled carbon nanotube films with molecule recognition function and lower capacitive background current.

Multilayer films of multiwalled carbon nanotubes (MWCNTs) with molecule recognition function were assembled on glassy carbon (GC) electrode with lower capacitive background current by two steps: first, MWCNTs interacted with beta-cyclodextrin (beta-CD) with the aid of sonication to form beta-CD-MWCNTs nanocomposite, then the beta-CD-MWCNTs nanocomposite was assembled on GC electrode using layer-by-layer (LBL) method based on electrostatic interaction of positively charged biopolymer chitosan and negatively charged MWCNTs. The assembled beta-CD-MWCNTs multilayer films were characterized by scanning electron microscopy (SEM) and cyclic voltammetry. The SEM indicated that the MWCNTs multilayer films with beta-CD were somewhat more compact than that of the MWCNTs multilayer films without beta-CD.

Detection of cytochrome c at biocompatible nanostructured Au-lipid bilayer-modified electrode.

The present work describes the dectection of cytochrome c (cyt c) at biocompatible aurum (Au) nanoparticle-structured supported bilayer lipid membrane (sBLM) modified with anionic sites. Au nanoparticles were directly deposited through sBLM modified with lauric acid (LA) to build a hybrid device of nanoscale electrode array via potential cycling in 10 mM HAuCl4 solution containing 0.1 M KCl.

A new antibody immobilization strategy based on electrodeposition of nanometer-sized hydroxyapatite for label-free capacitive immunosensor.

A new antibody immobilization strategy was proposed for the fabrication of a label-free capacitive immunosensor based on electrodeposition of nanometer-sized bioactive hydroxyapatite (HAP). By a procedure of constant current cathodal electrodeposition, a nano-HAP film with bioactivity was formed on a self-assembled beta-mercaptoethanol monolayer-modified gold electrode. A suitable amount of chitosan was added into the electrodeposition solution with the aim of obtaining a strong and homogeneous HAP-coating film.

A monitoring technique of piezoelectric impedance analysis used in tea polyphenols (TP) antimutagenic characteristics.

A new method was proposed for studying antimutagenic characteristics of tea polyphenols (TP) using piezoelectric impedance analysis during the Salmonella typhimurium strain TA100 growth process in the presence of mutagen 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (abbreviated NNK). Compared with the general method of antimutagenic investigation, the proposed method provided real-time, multidimensional response information about the antimutagenic characteristics during the bacterial growth process. The results showed that TP was allowed to be antimutagenic at the lowest concentration of 0.

Simultaneous voltammetry determination of dihydroxybenzene isomers by poly-bromophenol blue/carbon nanotubes composite modified electrode.

A novel modified electrode was constructed by electropolymerization of bromophenol blue at a multi-walled carbon nanotubes modified glassy carbon electrode. The electrode developed was used for the simultaneous determination of the isomers of dihydroxybenzene in environmental samples using a voltammetry method. There was a linear relationship over the range 10(-6)-10(-4 )mol L(-1) of hydroquinone, catechol and resorcinol; the detection limits was 3 x 10(-7) mol L(-1).

Direct electrochemistry and electrocatalysis of hemoglobin entrapped in semi-interpenetrating polymer network hydrogel based on polyacrylamide and chitosan.

Semi-interpenetrating polymer network (semi-IPN) hydrogel based on polyacrylamide (PAM) and chitosan was prepared to immobilize redox protein hemoglobin (Hb). The Hb-PAM-chitosan hydrogel film obtained has been investigated by scanning electron microscopy (SEM) and UV-VIS spectroscopy. UV-VIS spectroscopy showed that Hb kept its secondary structure similar to its native state in the Hb-PAM-chitosan hydrogel film.

Determination of trace thiocyanate with nano-silver coated multi-walled carbon nanotubes modified glassy carbon electrode.

Novel nano-silver coated multi-walled carbon nanotube composites were prepared and used to fabricate a modified electrode. The application of the nano-silver coated multi-walled carbon nanotube composites modified electrode for determination of trace thiocyanate is demonstrated for the first time. The influence of substrate, pH and interference of coexisting substances was investigated for response properties of the electrode.

Kinetics parameter estimation for the binding process of salicylic acid to human serum albumin (HSA) with capacitive sensing technique.

A novel method for real-time investigating the binding interaction between human serum albumin (HSA) and salicylic acid with capacitive sensing technique was successfully proposed. HSA was immobilized on the surface of a gold electrode modified with an insulating poly (o-phenylenediamine) (o-PD) film and colloid Au nanoparticles layers. The bioactivity of HSA was remained and major binding sites were available because of the excellent biocompatibility of gold nanoparticles.

Selective detection of dopamine in the presence of ascorbic acid by use of glassy-carbon electrodes modified with both polyaniline film and multi-walled carbon nanotubes with incorporated beta-cyclodextrin.

A simple, sensitive, and reliable method based on a combination of multi-walled carbon nanotubes with incorporated beta-cyclodextrin (beta-CD-MWNTs) and a polyaniline (PANI) film-modified glassy-carbon (GC) electrode has been successfully developed for determination of dopamine (DA) in the presence of ascorbic acid (AA). The PANI film had good anti-interference properties and long-term stability, because of the permselective and protective properties of the conducting redox polymer film. The acid-treated MWNTs with carboxylic acid functional groups promoted the electron-transfer reaction of DA and inhibited the voltammetric response of AA.

Immobilization of bovine serum albumin as a sensitive biosensor for the detection of trace lead ion in solution by piezoelectric quartz crystal impedance.

A biosensor based on bovine serum albumin (BSA) for the detection of lead (Pb(2+)) ion was developed and characterized. BSA was immobilized onto a colloidal Au-modified piezoelectric quartz crystal (PQC) as a biosensor for the detection of Pb(2+) ion by piezoelectric quartz crystal impedance (PQCI). Calibration curves for the quantification of Pb(2+) ion showed excellent linearity throughout the concentration range from 1.

Study on chromium (VI) reduction kinetics by Pseudomonas aeruginosa using a combined system of acoustic wave impedance analyzer and UV-vis spectrophotometer.

A novel system combining acoustic wave impedance (AWI) analyzer with UV-vis spectrophotometer was developed for the study of chromium (VI) reduction kinetics by Pseudomonas aeruginosa. AWI gave information about the growth of Pseudomonas aeruginosa, and UV-vis spectrophotometer gave information about the concentration of chromium (VI) simultaneously. A combined system response model, for chromium (VI) reduction kinetics at lower initial chromium (VI) concentrations, was derived and proved based on the novel system.

Application of a novel electrosynthesized polydopamine-imprinted film to the capacitive sensing of nicotine.

The application of novel electrosynthesized polydopamine (PDA)-imprinted film as a recognition element for the capacitive sensing of nicotine is reported. The PDA-imprinted film was electropolymerized directly on the gold electrode surface in the presence of nicotine without an additional self-assembled thiol sublayer. The compact PDA film has various functional groups that aid the imprinting procedure.

Low-potential nicotinamide adenine dinucleotide detection at a glassy carbon electrode modified with toluidine blue O functionalized multiwall carbon nanotubes.

The toluidine blue O (TBO) functionalized multiwall carbon nanotubes (MWNTs) nanomaterials (TBO-MWNTs) were prepared by assembling TBO onto the surface of a MWNTs modified glassy carbon (GC) electrode. Also TBO-MWNTs modified GC electrodes exhibiting a strong and stable electrocatalytic response toward beta-nicotinamide adenine dinucleotide (NADH) were described. Compared with a bare GC electrode, the TBO-MWNTs modified GC electrodes could decrease the oxidization overpotential of NADH by 730 mV, with a peak current at 0.