The therapeutic application of nanomaterials has been a focus of numerous studies in the past decade. Due to its unique redox properties, cerium oxide (ceria) is finding widespread use in the treatment of medical disorders caused by the reactive oxygen intermediates (ROI). The radicalscavenging role of ceria nanoparticles (nanoceria) have been established, as well as the autocatalytic ability of nanoceria to regenerate under various environmental conditions. The synthesis of nanoceria in biocompatible media has also been reported along with cell viability in order to determine the potential use of nanoceria in biomedical applications.

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We have made a comparative study of epitaxial growth of VO2 thin films on c-cut (0001) and r-cut (11¯02) sapphire substrates, and the semiconductor to metal transition (SMT) characteristics of these films have been correlated with their structural details. On c-sapphire, VO2 grows epitaxially in (002) orientation. These (002) oriented VO2 films have 60° twin boundaries due to three equivalent in-plane orientations. The epitaxial VO2 films on r-sapphire consisted of two orientations, namely (200) and (2¯11). The coexistence of these two orientations of VO2 has been explained on the basis of similarity of atomic arrangements in (200) and (2¯11) planes. The thermal hysteresis (ΔH), sharpness of the transition (ΔT), and the transition temperature for VO2 films on c-sapphire were found to be 4.8, 8.5, and 72.6 °C, respectively, which were higher than the corresponding values of 3.3, 5.4, and 60.3 °C for films on r-sapphire. The SMT temperature for VO2 films on c-sapphire was close to the bulk value of 68.0 °C. The significant decrease in transition temperature to 60.3 °C for VO2 films on r-sapphire has been attributed to the compressive strain along [002] direction of VO2.

A novel and advantageous approach to synthesis of H-shaped polybutadienes (H-PBd) is reported. The synthetic strategy employs classical anionic polymerization using high-vacuum techniques and utilizes a difunctional linking agent 4-(dichloromethylsilyl)diphenylethylene (DCMSDPE). The synthesis involves (a) growing a living PBd chain using s-BuLi as initiator in benzene at room temperature, (b) titration of DCMSDPE with living PBdLi, (c) addition of s-BuLi to activate the double bond of DPE, (d) subsequent addition of butadiene to generate a living “1/2 H”, which has two arms and half of the final cross-bar, and (e) finally coupling the two “1/2 H” molecules with dichlorodimethylsilane to produce an H-PBd, which has two arms attached to each end of the cross-bar. The weight-average molecular weight, number-average molecular weight, molecular weight distribution, intrinsic viscosity, and radius of gyration were characterized by multidetector size exclusion chromatography (SEC) coupled with a refractive index detector, a two-angle (15° and 90°) light scattering detector, and a Viscotek differential viscometer in tetrahydrofuran at 40 °C. The H-PBds showed narrow and symmetrical molecular weight distributions (polydispersity indices, PDI = 1.03−1.06). Furthermore, the use of light scattering detectors showed that there were no detectable high molecular weight, more highly branched components present in these materials. This is an important advantage of this novel approach over previous synthetic routes to H-polymers. The values of the branching parameters g (0.58−0.77) and g′ (0.60−0.75) in the thermodynamically good solvent, tetrahydrofuran, are consistent with values reported previously by Roovers and Toporowski for H polystyrenes in the good solvent toluene. Effects of architecture on the branching parameters are elucidated.

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Laser micromachining is becoming a common method for fabrication of microstructured medical devices. Developments in pulsed laser technology have made it possible to achieve precision machining of sub-micrometer features with minimal damage to the surrounding material. Several aspects of laser micromachining, including machining methods, types of lasers used in micromachining, and laser-material interaction, are discussed in this article. Biomedical applications of laser micromachining are also reviewed. The ablation behavior of silicon was examined as a function of laser energy, aperture, and repetition rate. In vitro studies showed that microscale grooves on silicon substrates may be used to orient human aortic vascular smooth muscle cells. We anticipate that the use of laser micromachining for modifying medical and dental devices will become more signifi cant over the coming years.

Atom transfer radical polymerization of methacrylates has been performed using hydrated natural clay as a support for a CuBr(2)-ligand complex and the supported clay catalyst has been recycled for 21 batch polymerizations without losing its activity.

Implantable blood glucose sensors have inadequate membrane-tissue interfaces for long term use. Biofouling and inflammation processes restrict biosensor membrane stability. An ideal biosensor membrane material must prevent protein adsorption and exhibit cell compatibility. In addition, a membrane must exhibit high porosity and low thickness in order to allow the biosensor to respond to analyte fluctuations. In this study, the structural, mechanical and biological properties of nanoporous alumina membranes coated with diamond-like carbon thin films were examined using scanning probe microscopy, nanoindentation and MTT viability assay. We anticipate that this novel membrane material could find use in immunoisolation devices, kidney dialysis membranes and other medical devices encountering biocompatibility issues that limit in vivo function.