The high conductive TiO(2) nanoneedles film is first employed as a support matrix for immobilizing model enzyme, cytochrome c (cyt c) to facilitate the electron transfer between redox enzymes and electrodes. Reversible and direct electron transfer of cyt c is successfully achieved at the nanostructured TiO(2) surface with the redox formal potential (E(0)') of 108.0 +/- 1.9 mV versus Ag|AgCl and heterogeneous electron transfer rate constant (k(s)) of 13.8 +/- 2.1 s(-1). Experimental data indicate that cyt c is stably immobilized onto the TiO(2) nanoneedles film and maintains inherent enzymatic activity toward H(2)O(2). On the basis of these results, the cyt c-TiO(2) nanocomposits film is capable of sensing H(2)O(2) at a suitable potential, 0.0 V (vs Ag|AgCl), where not only common anodic interferences like ascorbic acid, uric acid, 3,4-dihydroxyphenylacetic acid but also a cathodic interference, O(2), are effectively avoided. Besides high selectivity, the present biosensor for H(2)O(2) shows broad dynamic range and low detection limit. These remarkable analytical advantages, as well as the characteristic of TiO(2) nanoneedles film such as high conductivity, biocompatibility, and facile ability to miniaturize establishes a novel approach to detection of extracellular H(2)O(2) released from human liver cancer cells.

Seeing is believing: A direct, selective, and sensitive strategy for colorimetric visualization of cerebral dopamine has been developed for the first time using gold nanoparticles through the design of double molecular recognition (see picture). The simplicity of this method establishes a facile and reliable approach for monitoring cerebral species in brain chemistry, which may be related to physiological and pathological events.

In this article, cupric oxide (CuO) leafletlike nanosheets have been synthesized by a facile, low-cost, and surfactant-free method, and they have further been successfully developed for sensitive and selective determination of hydrogen sulfide (H 2 S) with high recovery ability. The experimental results have revealed that the sensitivity and recovery time of the present H 2 S gas sensor are strongly dependent on the working temperature. The best H 2 S sensing performance has been achieved with a low detection limit of 2 ppb and broad linear range from 30 ppb to 1.2 ppm. The gas sensor is reversible, with a quick response time of 4 s and a short recovery time of 9 s. In addition, negligible responses can be observed exposed to 100-fold concentrations of other gases which may exist in the atmosphere such as nitrogen (N 2 ), oxygen (O 2 ), nitric oxide (NO), cabon monoxide (CO), nitrogen dioxide (NO 2 ), hydrogen (H 2 ), and so on, indicating relatively high selectivity of the present H 2 S sensor. The H 2 S sensor based on the CuO nanosheets also shows strong recovery ability and long-term stability, probably due to the effective diffusion of gas toward the whole sensing surface, as well as the different mechanism of H 2 S gas sensor from those reported at CuO nanowires and CuO-SnO 2 nanocomposites, where a layer of CuS or Cu 2 S has formed on the CuO surface.

The pristine and defect-containing phosphorene as promising anode materials for Li-ion batteries (LIBs) have been systematically investigated by first-principles calculations.