Protein electrochemistry using aligned carbon nanotube arrays

The remarkable electrocatalytic properties and small size of carbon nanotubes make them ideal for achieving direct electron transfer to proteins, important in understanding their redox properties and in the development of biosensors. Here, we report shortened SWNTs can be aligned normal to an electrode by self-assembly and act as molecular wires to allow electrical communication between the underlying electrode and redox proteins covalently attached to the ends of the SWNTs, in this case, microperoxidase MP-11. The efficiency of the electron transfer through the SWNTs is demonstrated by electrodes modified with tubes cut to different lengths having the same electron-transfer rate constant.

Optimal sensor placement in linear arrays : part I - AoA based localization

In this paper, we examine the optimal linear separation requirements for AoA sensors, in order to achieve the best performance in estimating the position of a target subjected to noisy measurements. Cramer-Rao inequality and the corresponding Fisher information matrix are used to analyze the sensor-target geometry, in order to characterize localization performance with respect to the linear spacial distribution of sensors.

Optimal sensor placement in range based localization for linear arrays

This paper investigates the linear separation requirements for range sensors in order to achieve the optimal performance in estimating the position of a target from multiple and typically noisy sensor measurements. We analyze the sensor-target geometry in terms of the Cramer-Rao inequality and the corresponding Fisher information matrix, in order to characterize localization performance with respect to the linear special distribution.

Localized surface plasmon resonance: nano-sinusoid arrays

A new nano-sinusoid shape has recently been proposed, which offers the advantage of more resonance wavelength tunability than that offered by other sharp-tip nano-particles. In this paper, a one-dimensional (1D) chain of the nano-sinusoids is modelled, and results are compared with those describing chains of nano-triangles and nano-diamonds. It is demonstrated that the chain of nano-sinusoids provides more enhancement at hot spots than other examined nano-particle shapes. This enhancement is analytically quantified using the coupling constant values used in the electrostatic eigenmode method for analytically solving Maxwell's equations for the nano-plasmonic devices. In addition, investigating LSPR spectrum of two-dimensional (2D) arrays of NPs demonstrates existence of enhanced surface electric fields on hot spots of the outer rows of the array.

Facile synthesis of NiCo2O4 nanorod arrays on Cu conductive substrates as superior anode materials for high-rate Li-ion batteries

In this work, we report a mild and cost-effective solution method to directly grow Ni-substituted Co3O4 (ternary NiCo2O4) nanorod arrays on Cu substrates. Electrochemical impedance spectroscopy (EIS) measurements show that the values of the electrolyte resistance Re and charge-transfer resistance Rct of NiCo2O4 are 6.8 and 63.5 Ω, respectively, which are significantly lower than those of binary Co3O4 (10.4 and 122.4 Ω). This EIS characterization strongly confirms that the ternary NiCo2O4 anode has much higher electrical conductivity than that of the binary Co3O4 electrode materials, which should greatly enhance the lithium storage performances. Due to the well-aligned 1D nanorod microstructure and a higher electrical conductivity, these ternary NiCo2O4 nanorod arrays manifest high specific capacity, excellent cycling stability (a high reversible capacity of about 830 mA h g−1 was achieved after 30 cycles at 0.5 C) and high rate capability (787, 695, 512, 254, 127 mA h g−1 at 1 C, 2 C, 6 C 50 C and 110 C, respectively).

Synthesis and growth mechanism of Thin-film TiO2 nanotube arrays on focused-ion-beam micropatterned 3D isolated regions of titanium on silicon

In this paper, the fabrication and growth mechanism of net-shaped micropatterned self-organized thin-film TiO2 nanotube (TFTN) arrays on a silicon substrate are reported. Electrochemical anodization is used to grow the nanotubes from thin-film titanium sputtered on a silicon substrate with an average diameter of ?30 nm and a length of ?1.5 ?m using aqueous and organic-based types of electrolytes. The fabrication and growth mechanism of TFTN arrays from micropatterned three-dimensional isolated islands of sputtered titanium on a silicon substrate is demonstrated for the first time using focused-ion-beam (FIB) technique. This work demonstrates the use of the FIB technique as a simple, high-resolution, and maskless method for high-aspect-ratio etching for the creation of isolated islands and shows great promise toward the use of the proposed approach for the development of metal oxide nanostructured devices and their integration with micro- and nanosystems within silicon-based integrated-circuit devices.

Integrated High-Efficiency Pt/Carbon Nanotube Arrays for PEM Fuel Cells

A facile strategy to deposit Pt nanoparticles with various metal-loading densities on vertically aligned carbon nanotube (ACNT) arrays as electrocatalysts for proton exchange membrane (PEM) fuel cells is described. The deposition is achieved by electrostatic adsorption of the Pt precursor on the positively charged polyelectrolyte functionalized ACNT arrays and subsequent reduction by L-ascorbic acid. The application of the aligned electrocatalysts in fuel cells is realized by transferring from a quartz substrate to nafion membrane using a hot-press procedure to fabricate the membrane electrode assembly (MEA). It is shown that the MEA with vertically aligned structured electrocatalysts provides better Pt utilization than that with Pt on conventional carbon nanotubes or carbon black, resulting in higher fuel cell performance.

Neurophysiology of insects using microelectrode arrays: Current trends and future prospects

Simple to complex behaviors are directed by the brain, which possess nervous cells, called neurons. Mammals have billions of neurons, organized in networks, making their study difficult. Although methods have well evolved since the last century, studying a simpler model is the key to resolving neuronal communication. In this review, we demonstrate that insects are an excellent model and tool to understand neural mechanisms. Moreover, new technology, such as Microelectrodes Arrays (MEAs), is an innovative method which opens the possibility to study neuron clusters, rather than individual cells. A combined method of an insect model and MEAs technology may lead to great discoveries in neurophysiology, advancing progress in pharmacology, infectious and neurodegenerative diseases, agriculture maintenance and robotics.