Much effort has been directed at the fabrication of carbon nanotubes (CNTs)/polymer composites and the characterization of their physical properties. Among them, composites comprising CNTs and the biocompatible polymers are of special interest due to their potential for specific biomedical applications. we report the preparation of the MWCNT/poly(L-lactide) composite and the corresponding spectroscopic (Raman) and the microscopic (SEM, TEM) characterization. The electronic transport, thermal properties, and biocompatibility of this composite have also been investigated. The Raman spectroscopic analysis suggests the interaction between PLLA and MWCNT occurs mainly through the hydrophobic C-CH3 functional groups. The DC conductivity of the composite increases as the MWCNT loading is increased. Such behavior can be described by a percolation mechanism in which a percolation threshold at about 14 wt % MWCNT loading is observed with the maximum end conductivity of 0.1 S x cm(-1). The DSC study of the PLLA/MWCNT composite reveals that the MWCNTs in the composite have the effect of inducing crystallization and plasticizing the polymer matrix. The results from the cell culture test suggest that the presence of MWCNT in the composite inhibits the growth of the fibroblast cells.

Single walled carbon nanotubes (SWNTs) were dissolved in an acetonitrile + tert-butanol mixture, using the amphiphilic Ru-bipyridine complex NaRu(4-carboxylic acid-4′-carboxylate)(4,4′-dinonyl-2,2′bipyridine)(NCS) 2 as a surfactant. The assembly of the SWNT/Ru-bipyridine complex was adsorbed on the surface of LiFePO 4 (olivine), providing a material with approximately monolayer coverage by the Ru-bipyridine complex and ca. 0.04 wt % of SWNT. Electrodes fabricated from the surface-derivatized LiFePO 4 exhibited greatly enhanced activity for electrochemical Li + extraction/insertion compared to electrodes from commercial carbon-coated LiFePO 4 or from LiFePO 4 derivatized either by adsorption of sole Ru-bipyridine complex or by carbon nanotubes dispersed with the redox inactive pyrene butanoic acid. The SWNT backbone promotes the interfacial charge transfer between LiFePO 4 and the Ru-complex, whose redox potentials closely match each other. The nanotube-mediated redox wiring of virtually insulating electrode materials such as LiFePO 4 presents a novel strategy for application in high-energy lithium-ion batteries.

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Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions to fabrication challenges associated with chip sealing and demolding of polymer high-volume replication methods. UV-assisted thermal bonding was found to ensure a strong seal of the microstructures in the molded part without altering the geometry of the channels. In the DNA stretching device, a low aspect ratio nanoslit (1/200) connecting two larger micro-channels was used to stretch a 168.5 kbp DNA molecule, while in the other device single-HeLa cells were captured against a micro-aperture connecting two larger microfluidic channels. Different dry etching processes have been investigated for the master origination of the cell-capture device. The combination of a modified Bosch process and an isotropic polysilicon etch was found to ensure the ease of demolding by resulting in slightly positively tapered sidewalls with negligible undercut at the mask interface.