Generation of fuel from CO2 saturated liquids using a p-Si nanowire ‖ n-TiO2 nanotube array photoelectrochemical cell.

Light-driven, electrically biased pn junction photoelectrochemical (PEC) cells immersed in an electrolyte of CO(2) saturated 1.0 M NaHCO(3) are investigated for use in generating hydrocarbon fuels. The PEC photocathode is comprised of p-type Si nanowire arrays, with and without copper sensitization, while the photoanode is comprised of n-type TiO(2) nanotube array films.

Whole genome expression analysis reveals differential effects of TiO2 nanotubes on vascular cells.

The response of primary human endothelial (ECs) and vascular smooth muscle cells (VSMCs) to TiO2 nanotube arrays is studied through gene expression analysis. Microarrays revealed that nanotubes enhanced EC proliferation and motility, decreased VSMC proliferation, and decreased expression of molecules involved in inflammation and coagulation in both cell types. Networks generated from significantly affected genes suggest that cells may be sensing nanotopographical cues via pathways previously implicated in sensing shear stress.

Long-term small molecule and protein elution from TiO2 nanotubes.

In this study, TiO(2) nanotubes of various dimensions were used to elute albumin, a large protein molecule, as well as sirolimus and paclitaxel, common small molecule drugs. The nanotubes controlled small molecule diffusion for weeks and large molecule diffusion for a month. Drug eluted from the nanotubes was bioactive and decreased cell proliferation in vitro.

The effect of TiO2 nanotubes on endothelial function and smooth muscle proliferation.

In this study we investigate the effects of nanotubular titanium oxide (TiO(2)) surfaces on vascular cells. EC and VSMC response to nanotubes was investigated through immunofluorescence staining, scanning electron microscopy, 5-ethynyl-2'-deoxyuridine proliferation assays, and prostaglandin I(2) (PGI(2)) enzyme immunoassays. We found that the nanotubular surface significantly enhances EC proliferation and secretion of PGI(2).

Highly efficient solar cells using TiO(2) nanotube arrays sensitized with a donor-antenna dye.

Donor antenna dyes provide an exciting route to improving the efficiency of dye sensitized solar cells owing to their high molar extinction coefficients and the effective spatial separation of charges in the charge-separated state, which decelerates the recombination of photogenerated charges. Vertically oriented TiO(2) nanotube arrays provide an optimal material architecture for photoelectrochemical devices because of their large internal surface area, lower recombination losses, and vectorial charge transport along the nanotube axis. In this study, the results obtained by sensitizing TiO(2) nanotube arrays with the donor antenna dye Ru-TPA-NCS are presented.

The effects of cell density and device arrangement on the behavior of macroencapsulated beta-cells.

Over the last several decades, considerable research has focused on the development of cell encapsulation technology to treat a number of diseases, especially type 1 diabetes. One of the key advantages of cell encapsulation is that it permits the use of xenogenic tissue, particularly animal-derived cell lines. This is an attractive idea, because it circumvents the issue of a limited human organ supply.

Biocompatibility of nanoporous alumina membranes for immunoisolation.

Cellular immunoisolation using semi-permeable barriers has been investigated over the past several decades as a promising treatment approach for diseases such as Parkinson's, Alzheimer's, and Type 1 diabetes. Typically, polymeric membranes are used for immunoisolation applications; however, recent advances in technology have led to the development of more robust membranes that are able to more completely meet the requirements for a successful immunoisolation device, including well controlled pore size, chemical and mechanical stability, nonbiodegradability, and biocompatibility with both the graft tissue as well as the host. It has been shown previously that nanoporous alumina biocapsules can act effectively as immunoisolation devices, and support the viability and functionality of encapsulated beta cells.

Anodic growth of highly ordered TiO2 nanotube arrays to 134 microm in length.

Described is the fabrication of self-aligned highly ordered TiO(2) nanotube arrays by potentiostatic anodization of Ti foil having lengths up to 134 mum, representing well over an order of magnitude increase in length thus far reported. We have achieved the very long nanotube arrays in fluoride ion containing baths in combination with a variety of nonaqueous organic polar electrolytes including dimethyl sulfoxide, formamide, ethylene glycol, and N-methylformamide. Depending on the anodization voltage, pore diameters of the resulting nanotube arrays range from 20 to 150 nm.