The surface of boron-doped diamond (BDD) electrode is modified by the polymer film for the first time. The cationic polymer film of N,N-dimethylaniline (DMA) is electrochemically deposited on BDD electrode surface. This polymer (PDMA) film-coated BDD electrode is used as a sensor which selectively detect dopamine (DA) in the presence of ascorbic acid (AA). This electrode also can detect both DA and its metabolite, 3,4-dihydroxy phenyl acetic acid (DOPAC) in the presence of AA in the range of the physiological concentrations of these species. Favorable ionic interaction (i.e., electrostatic attraction) between the PDMA film and AA or DOPAC lowers their oxidation potentials and enhances the current response for AA and DOPAC compared to that at the bare electrode. The PDMA film also shows a hydrophobic interaction with DA and DOPAC. In cyclic voltammetric measurements, the PDMA film-coated electrode can successfully separate the oxidation potentials for AA and DA coexisting in the same solution and the separation is about 200 mV. AA oxidizes at more negative potential than DA. In square-wave voltammetry, the sensitivity of the PDMA film-coated BDD electrode for DA in the presence of higher concentration of AA is higher than that of the PDMA film-coated glassy carbon electrode. The hydrodynamic amperometric experiments confirm that the oxidation of AA is not affected by the oxidized product of DA and vice versa. So, unlike the bare electrode the catalytic oxidation of AA by the oxidized DA is eliminated at the PDMA film-coated BDD electrode. The sensitivities of the modified electrode for AA, DA and DOPAC, which are present in the same solution with their physiological concentration ratios, are calculated to be 0.070, 0.363 and 0.084 mA mM À1 , respectively. The modified electrode exhibits a stable and sensitive response to DA.

We report the nitrogen (N) doped nanocarbons with two different morphologies, arch and hollow structure, for supercapacitor (SCs) application. The simple co-axial electrospinning approach, subsequent leaching and carbonization process are employed to fabricate the N-doped carbon nanostructures. The fabricated N-doped arch and hollow nanocarbons exhibit high Ncontents of 9.02 and 8.73 wt%; high surface area of 619 and 557 m 2 g -1 ; total pore volumes of 0.6589 and 0.5681 cm 3 g -1 , respectively. The N-doped arch and hollow nanocarbons exhibit the maximum specific capacitances (Csp) of 417 and 371 F g -1 at 2 mV s -1 in three-electrode system and the Csp of 230 and 212 F g -1 at 2 mV s -1 for two-electrode system, respectively in 1M H2SO4 solution. The maximum energy densities of 8.4 and 7.5 Wh kg -1 are obtained for N doped arch and hollow nanocarbons, respectively. Further, these novel carbon nanostructures also deliver good cycle stabilities of 98% for 5000 cycles at a current density of 1 A g -1 . Such outstanding SCs electro-sorption ability is due to high micro-texture and high N-content characteristics of carbon nanostructures. Fig. 4. High resolution XPS spectra: C1s (a), N 1s (b) and O1s(c) for all samples; (d) schematic illustration of nitrogen functional groups for observed N1 s spectra.Fig. 6. The three electrode cell based electrochemical performance of all samples in 1 M H2SO4: (a) CVs at a 5mV s -1 scan rate, (b) Effect of scan rates on Csp, (c) Galvanostatic charge-discharge profiles at a 0.5 A g -1 current density and (d) Effect of current densities on Csp

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Both TiO 2 nanoparticles and carbon nanotubes have been usually utilized to modify the electrodes to enhance the detection sensitivity of biomolecular recognition. In this research, novel TiO 2 /CNT nanocomposites have been prepared and doped on the carbon paper as the modified electrodes. Subsequently, the redox behavior of the ferricyanide probe and the surface properties of the cancer cells coated on the modified electrodes have been investigated by using electrochemical and contact angle measurements. Compared with electrochemical signals on bare carbon paper and nanocomposite modified substrates, the significantly enhanced electrochemical signals on the modified electrodes covered with cancer cells have been observed. Meanwhile, different leukemia cells (i.e., K562/ ADM cells and K562/B.W. cells) could be also recognized because of their different electrochemical behavior and hydrophilic/hydrophobic features on the modified electrodes due to the specific components on the plasma membranes of the target cells. This new strategy may have potential application in the development of the biocompatible and multi-signal responsive biosensors for the early diagnosis of cancers.