Strengthened porous alumina membrane tube prepared by means of internal anodic oxidation

Itoh, Naotsugu; Tomura, Naohito; Tsuji, T.; Hongo, Motoyoshi

doi:10.1016/s1387-1811(97)00043-7

Cited by 41 publications

(16 citation statements)

References 7 publications

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“…The mean pore size of these membranes was approximately 75nm; however, it should be noted that other pore sizes can be obtained by changing the anodization voltage, with a correlation of ~1.29 nm/V. Since the membranes are actually incorporated into the tube, they are strong enough for easy handling and use, withstanding up to 32.6 MPa before failure [26]. Figure 1(a) shows the schematic of the fabrication process and Figure 1(b) shows an SEM image of a nanoporous alumina membrane with a mean pore diameter of 75nm.…”

Section: Fabricationmentioning

confidence: 99%

Biocompatibility of nanoporous alumina membranes for immunoisolation

Flamme¹,

Popat²,

Leoni³

et al. 2007

Biomaterials

159

108

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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, non-biodegradability, 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 β cells. The aim of this investigation was to assess the biocompatibility of the material with host tissue. The cytotoxicity of the capsule, as well as its ability to activate complement and inflammation was studied. Further, the effects of PEGmodification on the tissue response to implanted capsules were studied. Our results have shown that the device is non-toxic and does not induce significant complement activation. Further, in vivo work has demonstrated that implantation of these capsules into the peritoneal cavity of rats induces a transient inflammatory response, and that PEG is useful in minimizing the host response to the material.

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Section: Fabricationmentioning

confidence: 99%

Biocompatibility of nanoporous alumina membranes for immunoisolation

Flamme¹,

Popat²,

Leoni³

et al. 2007

Biomaterials

159

108

View full text Add to dashboard Cite

show abstract

“…16 Many other researchers have also examined the applicability of an AAO film as a membrane filter. [17][18][19][20][21][22][23] Now it is commercially available as an inorganic membrane for microfiltration. This membrane filter enjoys a number of advantages such as its high thermal stability, high resistance to organic solvents, and its unique pore structure.…”

Section: Synthesis Of Various Types Of Carbon Nanotubesmentioning

confidence: 99%

Synthesis of Various Types of Nano Carbons Using the Template Technique

Kyotani¹

2006

Bulletin of the Chemical Society of Japan

100

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Using uniform nanochannels of an aluminum anodic oxide film as a template, uniform and unique multiwalled carbon nanotubes can be synthesized with a selectivity of 100%. This technique allows one to precisely control the diameters and the length of nanotubes. Moreover, it is possible to chemically modify only the inner surface of carbon nanotubes and to prepare carbon nanotubes with a double coaxial structure of heteroatom-doped multiwalls. The test tube like carbon prepared by this technique was found to be dispersible in water without any post treatment. In addition to this one-dimensional approach, unique microporous carbon can be prepared by the template technique using zeolite Y. The resulting microporous carbons are characterized by their regular ordering, originating from the regularity of the parent zeolite. When the synthesis conditions were optimized, the specific surface area and the micropore volume of the zeolitetemplated carbon reach more than 4000 m 2 g À1 and 1.8 cm 3 g À1 , respectively. This review introduces such a templatemediated approach and highlights how useful and versatile the template technique is for the production of nano carbons.Carbon is an element with a unique ability to bond with itself principally via sp 3 (diamond-like) and sp 2 (graphite-like) hybridization. This versatility gives rise to a rich diversity of structural forms of solid carbon. Most of the materials dealt with in carbon science and industry are considered to be composed of mainly large polycyclic aromatic molecules. The differences in the shape of such macromolecules and the way the molecules assemble (how they stack and how they are connected to one another) again lead to an immense variety of possibilities. If one could control the shape of the macromolecules and the state of their assemblage at the nanometer level, it would be possible to prepare carbon materials with a unique nano structure, thereby expecting novel and useful characteristics from the structure. Such control is, however, a very difficult task, because the nano structure of carbon materials is not uniform by nature, except for perfect graphite and diamond. To illustrate, a drawing of the molecular structure of activated carbon is shown in Fig. 1, where many curved polycyclic aromatic molecules with different sizes and shapes are stacked and connected in very complicated ways, which is quite different from the uniform ordered porous structure of zeolite materials. It is easily understood from this molecular model that control of the shape and the position of each macromolecule in the model is very difficult and essentially impossible. For the ultimate control of the carbon nano structure, it is desirable to build up a carbon structure from small building blocks, i.e., synthesize the structure from small organic molecules using techniques developed in the field of organic synthesis. However, the organic syntheses of fullerenes and carbon nanotubes have not been achieved yet, even by using cutting-edge technology. One of the most powerful and pro...

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“…Similarly, Gong et al [119] reported the use of nanoporous alumina capsules, with highly ordered pores having diameters ranging from 25 to 55 nm, for controlled drug delivery. Anodization of the aluminum tubes resulted in a tubular porous alumina membrane, the process was based on the studies of Itoh et al [120]. The capsules were filled with fluorescent molecules of different molecular weight, and plugged with silicone.…”

Section: Porous Anodic Alumina To Create Nanodevicesmentioning

confidence: 99%

Nanostructured Materials Synthesized Using Electrochemical Techniques

Oliveira

Freitas

Mattoso

et al. 2008

Nanostructured Materials in Electrochemistry

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The visualization and/or handling of atom clusters, or even individual atoms, has been achieved during the past 25 years. One of the most practical instruments for this purpose is the tunneling microscope, which was invented during the 1980s. On such a small scale, materials properties are not the same as those of a macroscopicsized substance. The first occasion on which a scientist proposed atom handling was in 1959, when Professor Richard Feynman [1], during a lecture at the California Institute Technology, suggested that in the near future engineers would be able to take atoms and place them exactly where they wanted to, without -of courseinfringing the laws of Nature. Today, Professor Feynmans lecture, which was entitled There is Plenty of Room at the Bottom, is considered a milestone of the current technological and scientific era.We can define nanoscience as the study of the phenomena and handling of structures on the atomic, molecular and macromolecular scale, where at least one dimension is significantly less than the others. And nanotechnology includes the design, characterization, and production of devices and systems on a nanometer scale. This definition of nanotechnology is wide-ranging, it is not a specific technology, all of the techniques based on physics, chemistry, biology, materials science and engineering -and/or using computers -leading to the development of materials and tools in such a way that the common point among them is the reduced dimension in which they operate. Among these applications are: increased storage and processing capacity for computers; the creation of new mechanisms for drug delivery; and the production of materials which are both lighter and more resistant than metals and plastics. Additional benefits of nanotechnology developments include energy saving, environmental protection, and the more efficient use of increasingly scarce raw materials.Today, these new investigations into material fabrication are focused mainly on nanostructured devices or, at least, microdevices. The most-often used technique for j117 Nanostructured Materials in Electrochemistry. Edited by Ali Eftekhari

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Strengthened porous alumina membrane tube prepared by means of internal anodic oxidation

Cited by 41 publications

References 7 publications

Biocompatibility of nanoporous alumina membranes for immunoisolation

Biocompatibility of nanoporous alumina membranes for immunoisolation

Synthesis of Various Types of Nano Carbons Using the Template Technique

Nanostructured Materials Synthesized Using Electrochemical Techniques

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