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Mechanical alloying (MA) of Ni and P powders containing 20 and 12 wt% P was investigated. The structural changes of alloys during mechanical alloying were studied by X-ray diffractometry and transmission electron microscopy. The results showed that the interdiffusion of Ni and P elements during MA of Ni80P20 alloy leads to the development of Ni12P5 and Ni2P intermetallic compounds. However MA of the Ni88P12 alloy leads to the formation of an intermetallic compound (Ni3P) and a solid solution (α-Ni) as well as partially amorphous structure. Intermediate annealing of MAed Ni88P12 alloy does not promote the formation of fully amorphous structure. Furthermore, thermodynamic analysis using the Miedema’s semi-empirical model showed that the intermetallic phases are the most stable phases in Ni88P12 and Ni80P20 alloys during MA.

In recent years, amorphous alloys have received a considerable attraction because of their physical, mechanical and magnetic properties. Fe-Co alloy system has good soft magnetic properties (high magnetic saturation and high Curie point) which makes it suitable for high temperature magnetic applications. In this paper, the effect of different elements on glass forming ability (GFA) of Fe-Co system was evaluated based on Meidema semi-empirical model and the results were compared to mechanical alloying (MA) experiments. Si, B and P seem to be good elements to be added to Fe-Co alloys with respect to thermodynamics and kinetics requirements. Calculations based on extended Miedema model showed that enthalpy and Gibbs free energy changes for solid state amorphisation of Fe 70 Co 7 Si 8 B 8 P 7 were −179 (kJ mol −1 ) and −181 (kJ mol −1 ) respectively, but MA experiments in three different routes did not lead to amorphisation in this system. Also comparison between MA and melt spinning (MS) techniques showed GFA in both techniques are completely different.

Micropatterned biofunctional surfaces provide a wide range of applications in bioengineering. A key characteristic which is sought in these types of bio-interfaces is prevention of non-specific adhesion for enhanced biofunctionality and targeted binding. Lubricant-infused omniphobic coatings have exhibited superior performance in attenuating non-specific adhesion; however, these coatings completely block the surfaces and do not support targeted adhesion or patterning. In this work, we introduce a novel lubricant-infused surface with biofunctional micropatterned domains integrated within an omniphobic layer. This new class of micropatterned lubricant-infused surfaces simultaneously promotes localized and directed binding of desired targets, as well as repellency of undesired species, especially in human whole blood. Furthermore, this modification method is easily translatable to microfluidic devices offering a wider range of applications and improved performance for immunoassays in whole blood and inhibition of clot formation in microfluidic channels. The biofunctional micropatterned lubricant-infused surfaces were created through a bench-top straight forward process by integrating microcontact printing, chemical vapor deposition (CVD) of self-assembled monolayers (SAMs) of fluorosilanes, and further infusion of the SAMs with a bio-compatible fluorocarbon-based lubricant layer. The developed surfaces, patterned with anti-CD34 antibodies, yield enhanced adhesion and controlled localized binding of target biomolecules (e.g. antibodies) and CD34 positive cells (e.g. HUVECs) inside microfluidic devices, outperforming conventional blocking methods (e.g. bovine serum albumin (BSA) or poly(ethylene glycol) (PEG)) in buffer and human whole blood. These surfaces offer a straightforward and effective way to enhance blocking capabilities while preserving the biofunctionality of a micropatterned system in complex biological environments such as whole blood. We anticipate that these micropatterned biofunctional interfaces will find a wide range of applications in microfluidic devices and biosensors for enhanced and localized targeted binding while preventing non-specific adhesion.

This chapter presents various techniques that are employed to engineer and embed biofunctional interfaces in microfluidic platforms. Microfluidic systems exhibit high proficiency in rapid throughput and analysis, as well as small sample and reagent requirements. Achieving biofunctionalization, or controlled immobilization of specific biomolecules, within microchannels is of growing importance due to the rising capabilities of microfluidic systems in biomedical applications including three-dimensional cell culture platforms for tissue- and organ-on-a-chip technologies and point-of-care diagnostics. The formation of cell-functionalized microfluidic devices requires proper microfabrication techniques and biological patterning. Different coating and patterning processes can induce chemically reactive groups on the microchannel’s surface, which can then be used to establish a stable interaction between biomolecules of interest and the surface. The following sections explore widely used approaches to develop cell-laden microchannels: plasma- and silanization-based treatments, microcontact printing, microfluidic patterning, polymer grafting, and extracellular matrix-based hydrogel coating. Furthermore, this chapter introduces numerous surface blocking agents that prevent nonspecific adsorption of biomolecules and boost the sensitivity of biological assays. Through developing target-specific biofunctional interfaces, these techniques enhance the biological compatibility of microfluidic devices for a variety of microfluidic applications such as cell sorting, detection and isolation of circulating tumor cells, and organs-on-chips systems.

The high photocatalytic power of TiO2 nanoparticles has drawn great attention in environmental and medical applications. Coating surfaces with these particles enables us to benefit from self-cleaning properties and decomposition of pollutants. In this paper, two strategies have been introduced to coat ceramic tiles with TiO2 nanoparticles, and the self-cleaning effect of the surfaces on degradation of an organic dye under ultraviolent (UV) exposure is investigated. In the first approach, a simple one-step heat treatment method is introduced for coating, and different parameters of the heat treatment process are examined. In the second method, TiO2 nanoparticles are first aminosilanized using (3-Aminopropyl)triethoxysilane (APTES) treatment followed by their covalently attachment onto CO2 plasma treated ceramic tiles via N-(3-Dimethylaminopropyl)-N&prime, ethylcarbodiimide hydrochloride (EDC) and N-Hydroxysuccinimide (NHS) chemistry. We monitor TiO2 nanoparticle sizes throughout the coating process using dynamic light scattering (DLS) and characterize developed surfaces using X-ray photoelectron spectroscopy (XPS). Moreover, hydrophilicity of the coated surfaces is quantified using a contact angle measurement. It is shown that applying a one-step heat treatment process with the optimum temperature of 200 &deg, C for 5 h results in successful coating of nanoparticles and rapid degradation of dye in a short time. In the second strategy, the APTES treatment creates a stable covalent coating, while the photocatalytic capability of the particles is preserved. The results show that coated ceramic tiles are capable of fully degrading the added dyes under UV exposure in less than 24 h.

In this study, ethyl cellulose (EC) was treated with three different trimethoxysilane coupling agents. Various characterization techniques were employed to evaluate silane modification of EC compound. Microencapsulated phase change materials based on linseed oil (LO) core and un-treated and silane-treated EC shell materials with ratio of LO to EC (70:30) were prepared by solvent evaporation method. Morphology and shape of microcapsules were studied using optical microscopy and scanning electron microscopy (SEM) equipped with energy dispersive X-ray analyzer (EDAX). The size distribution of microcapsules was evaluated using a particle size analyzer. Fourier transform infrared spectra (FTIR) and nuclear magnetic resonance (NMR) analyses revealed chemical interactions between EC and three different types of trimethoxysilane. Chemical bond (Si O C) was formed by the reaction between Si OH and the hydroxyl group of EC. The thermo-gravimetric analysis (TGA) showed 6–12 wt% silane grafting on the EC compound. Microcapsules with a uniform spherical shape 5–35 μm in diameter and 0.5–2.0 μm in shell thickness were successfully prepared using either un-treated or silane-treated EC. SEM micrographs of the fractured surface of acrylic coating containing LO filled EC-microcapsules showed matrix structure for microcapsules, as results of silane treatment of EC shell material. The pre-silanized EC-microcapsules can improve mechanical properties of water-based self-healing coatings, due to better compatibility of microcapsules with polymeric matrix and possible chemical interactions between silane groups attached on EC-microcapsules and functional group of polymeric matrix.

Porous nanocomposites based on poly(e-caprolactone fumarate) (PCLF) resin matrix; N-vinyl pyrrolidone (NVP) as a reactive diluents and nanohydroxyapatite (nHA) filler were developed for bone tissue engineering applications. Nanocomposite scaffolds with three different contents of nHA [5, 10, and 20 (w/w %)] were prepared by thermal crosslinking of PCLF followed by particulate leaching and characterized in terms of mechanical properties (cyclic loading) and in vitro cell-material interaction by MTT assay and alkaline phosphatase activity measurements. Five osteoblastic cell lines were used to investigate the ability of the nanocomposites to support cell attachment, spreading, and proliferation after 3, 7, and 14 days. By adding the nHA filler phase, elastic modulus of the nanocomposites increased significantly. Scaffolds showed comparable biocompatibility to neat nHA particles, commercial bone graft (Bio-Oss) and tissue culture polystyrene as control groups. According to the results it can be concluded that these scaffolds are potential candidates for bone substitution because of their mechanical strength and bioactivity. (C) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.

The paper presents results of the finite element analysis of a coronary stent used in a treatment of blood vessel stenosis. This analysis is an efficient way to modify the design of stent and its performance. The work focuses on the Medtronic AVE Modular stent S7. A nonlinear model that contains balloon, stent, and vessel with plaque was used. A bi‐linear elasto‐plastic material model for stent and hyper‐elastic material models for balloon, artery, and plaque were assumed for material modeling. Stress distribution, outer diameter changes and bending behavior were investigated.