Hierarchical functionalisation of single-wall carbon nanotubes with DNA through positively charged pyrene

A simple and efficient method to link reversibly DNA to SWNTs via electrostatic interaction is reported. The DNA/nanotube hybrids are characterised by a combination of gel electrophoresis and AFM

Synthesis and self-assembly properties of fulleropyrrolidine prepared by Prato reaction

International audienceMolecular self-assembly is considered as a promising way to control the manufacture of new materials and their integration into hybrid devices with novel properties. In this work we have synthesized a fulleropyrrolidine bearing a phenylacetylene moiety via the Prato reaction. The characterization of the fulleropyrrolidine by nuclear magnetic resonance and optical spectroscopy is reported, and its self-assembly by crystallization study has been investigated according to the used solvents. If the solvent that effectively solubilizes fullerene derivative is tetrahydrofurane, the nano-square plates with 1–3 μ m in length and 50–100 nm in thickness are formed, while if the solvent is toluene, 5 μ m diameter ‘nano-flowers’ are obtained

Cofactor-specific covalent anchoring of cytochrome b 562 on a single-walled carbon nanotube by click chemistry †

International audienceRedox-active cytochrome b 562 with a tethered azide group on the heme propionate side chain is covalently linked to an acetylene moiety introduced on the sidewall of a single-walled carbon nanotube (SWNT) by copper-catalyzed click chemistry forming a triazole ring with the heme active site directly linked to the SWNT. The cytochrome b 562 –SWNT hybrid is characterized by electrochemistry and atomic force microscopy. Interfacing redox-active enzymes with electrode materials is a key technology used in the development of high performance biosensors and biofuel cells. 1–3 Recent advances in carbon nanomaterials have enabled us to design hybrid systems with linked enzymes. Carbon nanotubes (CNTs), of the single-or multi-walled type, are promising building blocks for fabrication of hybrid materials. 4–8 CNTs have large surface areas, high strength, chemical stability, and attractive electronic properties. CNTs have also provided a wide variety of synthetic tools applicable for introduction of a range of substituents for linking the enzymes. A copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction is a widely utilized method used to form a covalent linkage which includes a triazole ring between building blocks containing azide and alkyne groups. 9,10 The CuAAC reaction has thus been used in organic synthesis, bio-conjugation chemistry, and surface chemistry. This powerful coupling reaction can be applied in efforts to efficiently tailor the chemical modication of single-walled CNTs (SWNTs) to construct hybrid materials 11–13 including enzymes. 14 Redox-active hemoproteins form a major class of enzymes that are useful for constructing enzyme-immobilized electrodes due to their diverse functions including electron transfer, catal-ysis, and sensing. 15–25 Many hemoproteins possess a replaceable heme b cofactor in the heme pocket, enabling immobilization on the electrode via the heme–heme pocket interaction. 26–45 In this paper, we demonstrate specically oriented covalent immobili-zation of azide-linked cytochrome b 562 (CYT) on the sidewall of SWNT using the CuAAC reaction (Fig. 1). The advantage of this method which uses a replaceable heme tethered to an azide moiety, lies in the wide range of applications for functionaliza-tion of wild-type hemoproteins. The characterization and elec-trochemical properties of the covalently-linked hybrid materials of SWNT and cytochrome b 562 are described. Fig. 1 (a) SWNT with covalently-linked cytochrome b 562 and (b) the preparation scheme using a copper-catalyzed azide–alkyne cyclo-addition (CuAAC) reaction

All solution-processed organic photocathodes with increased efficiency and stability via the tuning of the hole-extracting layer †

International audiencePhotoelectrodes based on solution-processed organic semiconductors are emerging as low-cost alternatives to crystalline semiconductors and platinum. In this work, the performance and stability of P3HT:PCBM\MoS 3-based photocathodes are considerably improved by changing the hole-extracting layer (HEL). Oxides such as reduced graphene oxide, nickel oxide or molybdenum oxide are deposited via solution processes. With MoO x , a photocurrent density of 2 mA cm À2 during 1 h is obtained with the processing temperature lower than 150 C – thus compatible with flexible substrates. Furthermore, we show that the performances are directly correlated with the work function of the HEL material, and the comparison with solid-state solar cells shows that efficient HELs are not the same for the two types of devices