Nanopore Gradients on Porous Aluminum Oxide Generated by Nonuniform Anodization of Aluminum

Kant, Kamal; Low, Suet P.; Marshal, Asif; Shapter, Joseph G.; Lošić, Dušan

doi:10.1021/am100502u

Cited by 42 publications

(40 citation statements)

References 36 publications

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“…For this purpose, we adjusted the applied current density to a value of 16 mA cm −2 , allowing the preparation of a grooved template in 90 s. The resulting periodically grooved template exhibited a mean groove width of 36 nm (Figure c). Although parallel aligned pores with controllable size has been previously described, the formation of periodically grooved AAO surfaces with periodicities in the nanometer regime has not been reported to the best of our knowledge. The generation of such structures could be explained by a voltage change during the anodization process.…”

Section: Resultsmentioning

confidence: 91%

SERS Platforms of Plasmonic Hydrophobic Surfaces for Analyte Concentration: Hierarchically Assembled Gold Nanorods on Anodized Aluminum

Tebbe

Cherepanov

Skorb

et al. 2014

Part & Part Syst Charact

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Efficient and homogeneous surface‐enhanced Raman scattering (SERS) substrates are usually prepared using lithographic approaches, physical evaporation, or in situ chemical reduction. However, these approaches are time‐consuming, expensive, and very difficult to upscale. Alternatively, template‐assisted approaches using colloidal suspensions of preformed nanoparticles have become more popular because of their low cost, fast production, and ability to be scaled up easily. One of the limitations of these methods is the dimensions of the structured surfaces. In this context, a new method for designing low‐cost, up‐scalable surface patterns that match building block dimensionality based on anodization of aluminum, enabling a hierarchical organization of anisotropic nanoparticles, is presented. The proposed new technology starts with anodized aluminum oxide with regular parallel linear periodicities. To produce a highly efficient plasmonic surface, gold nanorods are assembled into parallel lines where the long axes of the Au rods are also oriented along the substrate lines, thus inducing reproducible tip‐to‐tip plasmonic coupling with the corresponding generation of highly active hotspots. Additionally, this advanced material presents an inherent hydrophobicity that can be exploited as a method for concentration of analytes on the surface. SERS detection is demonstrated with benzenethiol and 2‐naphtoic acid.

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Section: Resultsmentioning

confidence: 91%

SERS Platforms of Plasmonic Hydrophobic Surfaces for Analyte Concentration: Hierarchically Assembled Gold Nanorods on Anodized Aluminum

Tebbe

Cherepanov

Skorb

et al. 2014

Part & Part Syst Charact

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“…selective separation and absorption of target molecules) 5, 6, biotechnology and nanomedicine (e.g. cell culturing and drug delivery) 7, 8 and so on. So far, several anodization strategies have been used to generate modulations of the pore diameter in NAA.…”

Section: Introductionmentioning

confidence: 99%

Understanding and morphology control of pore modulations in nanoporous anodic alumina by discontinuous anodization

Santos¹,

Vojkuvka²,

Alba³

et al. 2012

Physica Status Solidi (a)

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Here, we report on an electrochemical approach so‐called discontinuous anodization (DA) for controlling the generation of pore modulations in nanoporous anodic alumina (NAA) under self‐ordering conditions. In this method, the anodization of aluminium is performed by voltage pulses under mild anodization regime and thermal‐acidic conditions. Furthermore, we perform an exhaustive and systematic study about the relationship between the pore modulation morphology and the main anodization parameters (i.e. acid electrolyte temperature and relax time between consecutive voltage pulses). The generation mechanism of the pore modulations is associated with the formation of a gel‐like layer under these thermal‐acidic conditions and its subsequent detachment during the beginning of each voltage pulse. All this makes it possible to control the pore modulation morphology in NAA at will, what is crucial for developing new nanostructures with accurately controlled geometry for such purposes as nanofluidics, magnetic nanostructures, optical biosensors, templates, selective molecular separators and so forth. A three‐dimensional network based on NAA with controlled geometry: The DA by voltage pulses under hydrothermal conditions yields an accurate control over the pore modulation morphology. Therefore, the structure of the resulting 3D‐NAA network can be designed at will for later applications.

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“…[17] They would also be useful in the development of single-cell platforms to screen the best nanoscale architectures for the desired response of a specific cell type. [17] They would also be useful in the development of single-cell platforms to screen the best nanoscale architectures for the desired response of a specific cell type.…”

mentioning

confidence: 99%

Ultrasonically Produced Porous Sponge Layer on Titanium to Guide Cell Behavior

et al. 2016

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The adhesion of cells to surfaces, as well as their proliferation, migration, and differentiation, is guided not only by chemical functionalization but also by surface nanostructuring, nanotopography. [1] Nano-patterned titanium surfaces are one example in which the scale of patterning controls the size of focal adhesions. [2] Nanoscale disorder in surface structure can be used to stimulate cell differentiation [3] or can also be used to maintain stem cell phenotypes over long times. [4] Nanoroughness modulates cells interactions and function via mechanosensing. [5] These all suggest that the careful control of surface nanostructure of such important as titanium (Ti) biomaterial [6] could be a useful tool to achieve desired cellular responses.We first time highlight that ultrasonic treatment is able to produce surface porous sponge layer in Ti. We find it great technological advances that Ti can be also modified with highintensity ultrasonic treatment. We really think that presenting high-intensity ultrasonic technique for Ti nanostructuring increases interest of scientists to the technique. Great advantage of our methodology is a large number of synthetic parameters which can be optimized to tune surface nanostructuring in a controllable manner. Moreover, this methodology will be very interesting in future to provide single-step hybrids and effective loading of porous structures with active chemicals. We compare our methodology with more known for bio-application anodization for surface nanostructuring.Anodization leads to TiO 2 nanotube arrays covering the surface of titanium and is one of the most studied methods to develop porous surface nanotopographies with controlled pore sizes. [6] It has been demonstrated in cell culture experiments on TiO 2 nanotube arrays of different sizes that adhesion, proliferation, and migration of mesenchymal stem cells are optimal on ordered nano-pore arrays with spacings in the range of 15-30 nm; these length scales also lead to significantly less apoptosis than on 100 nm structures. [7,8] It should be taken into account that nanostructuring does affect cell function at many levels but in a cell specific manner, and smaller surface features (50 nm) tend to favor cell proliferation in comparison to larger features (300 nm). [9] Anodization requires a conductive substrate, is difficult to use over large surface areas, and uses aggressive media for synthesis. [6] Recently, we have shown that ultrasonic treatments in aqueous media can produce surface porosities in various size-ranges also below 100 nm in metals such as Al or Mg. [10] Here, we demonstrate that such nanostructuring can also be effectively induced in an important biomaterial, titanium, by investigating its influence on cell behavior in comparison to the well-established electrochemical method.To this end, we investigate the response in terms of morphology, adhesion, proliferation, and differentiation of C2C12 cells on a glass substrate and on three different titanium/TiO 2 surfaces: a titania mesoporous sponge layer (...

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Nanopore Gradients on Porous Aluminum Oxide Generated by Nonuniform Anodization of Aluminum

Cited by 42 publications

References 36 publications

SERS Platforms of Plasmonic Hydrophobic Surfaces for Analyte Concentration: Hierarchically Assembled Gold Nanorods on Anodized Aluminum

SERS Platforms of Plasmonic Hydrophobic Surfaces for Analyte Concentration: Hierarchically Assembled Gold Nanorods on Anodized Aluminum

Understanding and morphology control of pore modulations in nanoporous anodic alumina by discontinuous anodization

Ultrasonically Produced Porous Sponge Layer on Titanium to Guide Cell Behavior

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