A nanoporous interferometric micro-sensor for biomedical detection of volatile sulphur compounds

This work presents the use of nanoporous anodic aluminium oxide [AAO] for reflective interferometric sensing of volatile sulphur compounds and hydrogen sulphide [H2S] gas. Detection is based on changes of the interference signal from AAO porous layer as a result of specific adsorption of gas molecules with sulphur functional groups on a gold-coated surface. A nanoporous AAO sensing platform with optimised pore diameters (30 nm) and length (4 µm) was fabricated using a two-step anodization process in 0.3 M oxalic, followed by coating with a thin gold film (8 nm). The AAO is assembled in a specially designed microfluidic chip supported with a miniature fibre optic system that is able to measure changes of reflective interference signal (Fabry-Perrot fringes). When the sensor is exposed to a small concentration of H2S gas, the interference signal showed a concentration-dependent wavelength shifting of the Fabry-Perot interference fringe spectrum, as a result of the adsorption of H2S molecules on the Au surface and changes in the refractive index of the AAO. A practical biomedical application of reflectometric interference spectroscopy [RIfS] Au-AAO sensor for malodour measurement was successfully shown. The RIfS method based on a nanoporous AAO platform is simple, easy to miniaturise, inexpensive and has great potential for development of gas sensing devices for a range of medical and environmental applications

Nanoengineered drug-releasing Ti wires as an alternative for local delivery of chemotherapeutics in the brain

The blood–brain barrier (BBB) blocks the passage of active molecules from the blood which makes drug delivery to the brain a challenging problem. Oral drug delivery using chemically modified drugs to enhance their transport properties or remove the blocking of drug transport across the BBB is explored as a common approach to address these problems, but with limited success. Local delivery of drugs directly to the brain interstitium using implants such as polymeric wafers, gels, and catheters has been recognized as a promising alternative particularly for the treatment of brain cancer (glioma) and neurodegenerative disorders. The aim of this study was to introduce a new solution by engineering a drug-releasing implant for local drug delivery in the brain, based on titanium (Ti) wires with titania nanotube (TNT) arrays on their surfaces. Drug loading and drug release characteristics of this system were explored using two drugs commonly used in oral brain therapy: dopamine (DOPA), a neurotransmitter agent; and doxorubicin (DOXO), an anticancer drug. Results showed that TNT/Ti wires could provide a considerable amount of drugs (>170 μg to 1000 μg) with desirable release kinetics and controllable release time (1 to several weeks) and proved their feasibility for use as drug-releasing implants for local drug delivery in the brain

Drug-eluting Ti wires with titania nanotube arrays for bone fixation and reduced bone infection

Current bone fixation technology which uses stainless steel wires known as Kirschner wires for fracture fixing often causes infection and reduced skeletal load resulting in implant failure. Creating new wires with drug-eluting properties to locally deliver drugs is an appealing approach to address some of these problems. This study presents the use of titanium [Ti] wires with titania nanotube [TNT] arrays formed with a drug delivery capability to design alternative bone fixation tools for orthopaedic applications. A titania layer with an array of nanotube structures was synthesised on the surface of a Ti wire by electrochemical anodisation and loaded with antibiotic (gentamicin) used as a model of bone anti-bacterial drug. Successful fabrication of TNT structures with pore diameters of approximately 170 nm and length of 70 μm is demonstrated for the first time in the form of wires. The drug release characteristics of TNT-Ti wires were evaluated, showing a two-phase release, with a burst release (37%) and a slow release with zero-order kinetics over 11 days. These results confirmed our system's ability to be applied as a drug-eluting tool for orthopaedic applications. The established biocompatibility of TNT structures, closer modulus of elasticity to natural bones and possible inclusion of desired drugs, proteins or growth factors make this system a promising alternative to replace conventional bone implants to prevent bone infection and to be used for targeted treatment of bone cancer, osteomyelitis and other orthopaedic diseases

Diatom culture media contain extracellular silica nanoparticles which form opalescent films

Diatoms are unicellular photosynthetic algae with enormous diversity of patterns in their silica structures at the nano- to micronscale. In this study, we present results, which support the hypothesis that silica nanoparticles are released into the diatom culture medium. Formation of an opalescent film by the self-assembly of silica nanoparticles produced in the growth medium of diatoms. This film was formed on the filter paper from the culture medium of a Coscinodiscus sp. culture. A number of diatoms with partially opened valves were observed on the film surface under light microscopy and SEM, which indicates that cell contents inside of diatoms had been released into the culture solution. AFM images of produced an opalescent films show ordered arrays of silica nanoparticles with different diameters depending on the colors observed by light microscopy. The film forming silica nanoparticles are either released by the diatoms during reproduction or after cell death This approach provides an environmentally friendly means for fabricating silica nanoparticles, decorative coatings and novel optical materials. © 2008 SPIE.Dusan Losic, James G. Mitchell, Nicolas H. Voelcke

Controlling the surface functionalities of nanoporous alumina membranes

A new approach for controlling and to functionalise nanoporous anodic alumina oxide (AAO) membranes is described. Our approach is predicated on the remarkable stability of the silanised AAO surface during anodisation. Well ordered nanoporous AAO membranes with different external surface properties compared to the internal pore surface properties were prepared and characterised

Gold nanotube membranes: fabrication of controlled pore geometries and tailored surface chemistries

This study concerns the fabrication, chemical modification and characterisation of gold nanotube membranes using porous alumina (PA) membranes as templates. Electroless deposition was used to finely coat membranes with gold, forming gold nanotubes within the pores. PA templates were fabricated with straight and shaped pores thus allowing the fabrication of a wide range of gold nanotube geometries. The gold deposition process provides control over the pore size of the membrane, where pore sizes can be reduced to molecular dimensions. Chemical sensitivity was introduced into the membrane through the addition of self assembled monolayers (SAMs) of thiols. Characterisation of thiol assembly within the pores of the membrane was investigated using confocal Raman

Pore spanning lipid bilayers on silanised nanoporous alumina membranes

http://spiedigitallibrary.org/journals/doc/SPIEDL-home/proc

Perancangan Dan Implementasi Augmented Reality Sebagai Media Promosi Penjualan Perumahan

Untuk melakukan promosi sebuah Perumahan banyak cara yang dapat dilakukan, misalnya dengan menggunakan brosur yang mana informasinya disampaikan dalam media dua dimensi, maket yang mana informasinya sudah dapat disampaikan dalam media tiga dimensi tetapi harus memerlukan ruang yang tidak sedikit untuk mewujudkannya demi mendapatkan hasil yang maksimal. Yang menjadi masalah disini adalah bagaimana menjadikan suatu informasi tersebut menjadi interaktif dan lebih menarik bagi konsumen. Dengan menggunakan teknik promosi berbasis augmented reality yang dibuat dengan menggunakan ARTool Kit sebagai komponen yang utama dan dengan menggunakan 3DS Max sebagai software untuk menghasilkan gambar yang menarik. Proses perancangan dan pembuatan teknik promosiini akan menggunkan metode waterfall. Kelebihan dari model waterfall adalah struktur tahap pengembangan sistem jelas, dokumentasi dihasilkan disetiap tahap pengembangan, dan sebuah tahap dijalankan setelah tahap sebelumnya selesai dijalankan (tidak ada tumpang tindih pelaksanaan tahap). Hasil dari perancangan aplikasi ini adalah terealisasinya suatu aplikasi untuk kepentingan promosipenjualan Perumahan yang lebih menarik dan interaktif dengan konsumen berbasis augmented reality. Dengan adanya aplikasi ini diharapkan metode promosi dapat berkembang dengan lebih menarik dan tentunya dengan mengandalkan teknologitanpa membutuhkan ruang yang banyak untuk mencapai hasil yang maksimal

Estimation of anisotropic permeability in trabecular bone based on microCT imaging and pore-scale fluid dynamics simulations

Highlights - A representative volume element (RVE) size of 2 ×2 × 2 mm3 is sufficient to represent bovine trabecular bone microstructure and corresponding fluid flow properties. - Using periodic boundary conditions, with a mesh size >125,000 elements, provides the most accurate values for respective bone permeability data. - Comparison of bone specimens with respect to porosity does not provide accurate information about permeability. - For similarity between specimens based on mechanical properties, both magnitude of principal permeability and anisotropic ratio, need to be similar. - Comparison of permeabilities of our bovine sternum bone specimens with other bone samples from the literature, showed excellent agreement. Abstract In this paper, a comprehensive framework is proposed to estimate the anisotropic permeability matrix in trabecular bone specimens based on micro-computed tomography (microCT) imaging combined with pore-scale fluid dynamics simulations. Two essential steps in the proposed methodology are the selection of (i) a representative volume element (RVE) for calculation of trabecular bone permeability and (ii) a converged mesh for accurate calculation of pore fluid flow properties. Accurate estimates of trabecular bone porosities are obtained using a microCT image resolution of approximately 10 μm. We show that a trabecular bone RVE in the order of 2 × 2 × 2 mm3 is most suitable. Mesh convergence studies show that accurate fluid flow properties are obtained for a mesh size above 125,000 elements. Volume averaging of the pore-scale fluid flow properties allows calculation of the apparent permeability matrix of trabecular bone specimens. For the four specimens chosen, our numerical results show that the so obtained permeability coefficients are in excellent agreement with previously reported experimental data for both human and bovine trabecular bone samples. We also identified that bone samples taken from long bones generally exhibit a larger permeability in the longitudinal direction. The fact that all coefficients of the permeability matrix were different from zero indicates that bone samples are generally not harvested in the principal flow directions. The full permeability matrix was diagonalized by calculating the eigenvalues, while the eigenvectors showed how strongly the bone sample's orientations deviated from the principal flow directions. Porosity values of the four bone specimens range from 0.83 to 0.86, with a low standard deviation of ± 0.016, principal permeability values range from 0.22 to 1.45 ⋅ 10 −8 m2, with a high standard deviation of ± 0.33. Also, the anisotropic ratio ranged from 0.27 to 0.83, with high standard deviation. These results indicate that while the four specimens are quite similar in terms of average porosity, large variability exists with respect to permeability and specimen anisotropy. The utilized computational approach compares well with semi-analytical models based on homogenization theory. This methodology can be applied in bone tissue engineering applications for generating accurate pore morphologies of bone replacement materials and to consistently select similar bone specimens in bone bioreactor studies

A Unique 3D Nitrogen-Doped Carbon Composite as High-Performance Oxygen Reduction Catalyst

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).The synthesis and properties of an oxygen reduction catalyst based on a unique 3-dimensional (3D) nitrogen doped (N-doped) carbon composite are described. The composite material is synthesised via a two-step hydrothermal and pyrolysis method using bio-source low-cost materials of galactose and melamine. Firstly, the use of iron salts and galactose to hydrothermally produceiron oxide (Fe2O3) magnetic nanoparticle clusters embedded carbon spheres. Secondly, magnetic nanoparticles diffused out of the carbon sphere when pyrolysed in the presence of melamine as nitrogen precursor. Interestingly, many of these nanoparticles, as catalyst-grown carbon nanotubes (CNTs), resulted in the formation of N-doped CNTs and N-doped carbon spheres under the decomposition of carbon and a nitrogen environment. The composite material consists of integrated N-doped carbon microspheres and CNTs show high ORR activity through a predominantly four-electron pathway