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Material Interactions (material + interaction)
Selected AbstractsMapping the Interactions among Biomaterials, Adsorbed Proteins, and Human Embryonic Stem CellsADVANCED MATERIALS, Issue 27 2009Ying Mei An integrated high-throughput polymer synthesis and rapid material/protein/cell interaction assays were developed to optimize stem cell microenvironments. Microarrayed polymers were synthesized and studied for the ability to support the growth of partially differentiated human embryonic stem cells. In parallel, a programmed laser scanning cytometry system was developed to allow for rapid quantification of cell material interaction. [source] An ultrastructural study of cellular response to variation in porosity in phase-pure hydroxyapatiteJOURNAL OF MICROSCOPY, Issue 2 2004B. ANNAZ Summary Hydroxyapatite has been shown to be biocompatible and bioactive. Incorporation of porosity has been shown to enhance osteointegration; however, difficulty in controlling the extent and type of porosity has limited investigation into determining the role of both macro- and microporosity. The current investigation reports on the synthesis of four types of phase-pure hydroxyapatite with varying levels of porosity (HA1,HA4), and with defined levels of macro- and microporosities. Transmission electron microscopy was used to evaluate qualitatively the effect of these two parameters on cell,material interactions following a 30-day incubation period. Biological mineralization was observed within vesicles and the needle-like minerals were confirmed as hydroxyapatite using X-ray microanalysis. This demonstrated the suitability of primary human osteoblast-like cells as a tool to assess the extent of mineralization. Furthermore, internalization of hydroxyapatite particles was observed. Our findings show that the variation in macro- and microporosity does not affect the extent of cell,material interaction, with collagen synthesis evident in all samples. [source] Aragonite crystalline matrix as an instructive microenvironment for neural developmentJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 8 2008H. Peretz Abstract The ability to mimic cell,matrix interactions in a way that closely resembles the natural environment is of a great importance for both basic neuroscience and for fabrication of potent scaffolding materials for nervous tissue engineering. Such scaffolding materials should not only facilitate cell attachment but also create a microenvironment that provides essential developmental and survival cues. We previously found that porous aragonite crystalline matrices of marine origin are an adequate and active biomaterial that promotes neural cell growth and tissue development. Here we studied the mechanism underlying these neural cell,material interactions, focusing on the three-dimensional (3D) surface architecture and matrix activity of these scaffolds. We introduced a new cloning technique of the hydrozoan Millepora dichotoma, through which calcein or 45Ca2+ were incorporated into the organism's growing skeleton and neuronal cells could then be cultured on the labelled matrices. Herein, we describe the role of matrix 3D architecture on neural cell type composition and survival in culture, and report for the first time on the capacity of neurons and astrocytes to exploit calcium ions from the supporting biomatrix. We found that hippocampal cells growing on the prelabelled aragonite lattice took up aragonite-derived Ca2+, and even enhanced this uptake when extracellular calcium ions were chelated by EGTA. When the aragonite-derived Ca2+ uptake was omitted by culturing the cells on coral skeletons coated with gold, cell survival was reduced but not arrested, suggesting a role for matrix architecture in neural survival. In addition, we found that the effects of scaffold architecture and chemistry on cell survival were more profound for neurons than for astrocytes. We submit that translocation of calcium from the biomaterial to the cells activates a variety of membrane-bound signalling molecules and leads to the subsequent cell behaviour. This kind of cell,material interaction possesses great potential for fabricating advanced biomaterials for neural tissue-engineering applications. Copyright © 2008 John Wiley & Sons, Ltd. [source] Impact of environmental conditions on the performance of cartonboard skilletsPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2005C. Berry Abstract This paper discusses the importance of understanding machine,material interaction for achieving high process efficiencies. In the area of cartoning, the performance of cartonboard and hence the efficacy of the machine,material interactions can be significantly altered by changes in environmental conditions. In this paper, the process of carton conversion is dealt with and its performance during creasing, folding and subsequent erection is considered. An experimental programme was created to investigate the effect of moisture on the carton performance and in particular the important attribute of ,spring back'. The results of the experimental investigation are discussed with respect to the accepted understanding of the behaviour of cellulose structures. From this discussion, the implications for processing of cartonboard are identified and guidelines and considerations for storage and handling are proposed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Quantitative Analysis of Human Platelet Adhesions Under a Small-Scale Flow DeviceARTIFICIAL ORGANS, Issue 4 2010Katsuko S. Furukawa Abstract To realize real-time evaluation of human platelet adhesions onto material surfaces with small volumes of human platelet suspensions, we developed an apparatus consisting of a modified cone and plate-type viscometer, combined with an upright epi-fluorescence microscope. The apparatus allowed real-time evaluation of platelet,material interactions and the initial event of thrombus formation, using small platelet suspension volumes (7.5 µL) under shear flow conditions. To study the dynamic behavior of platelet,material interaction, we chose five representative opaque and transparent materials: acrylate resin (AC), polytetrafluoroethylene (PTFE), polyvynylchrolide (PVC), glass, and a monolayer of human normal umbilical cord vein endothelial cells (EC) on glass under shear flow conditions. The values of adhesiveness of human platelets to the test materials in descending order were as follows: AC > PTFE > PVC > glass > human EC. Under this new small-scale flow system, we could obtain highly reproducible data, which were comparable with results from a previously developed large-scale flow system. Therefore, the newly developed cone and plate-type rheometer is a useful instrument for testing and screening materials, and allows precise quantitative evaluation of human platelet adhesion. [source] Material civilization: things and societyTHE BRITISH JOURNAL OF SOCIOLOGY, Issue 2 2006Tim Dant Abstract This paper argues that although classical sociology has largely overlooked the importance of social relations with the material world in shaping the form of society, Braudel's concept of ,material civilization' is a useful way to begin to understand the sociological significance of this relationship. The limitations of Braudel's historical and general concept can be partially overcome with Elias's analysis of the connection between ,technization' and ,civilization' that allows for both a civilizing and a de-civilizing impact of emergent forms of material relation that both lengthen and shorten the chains of interdependence between the members of a society. It is suggested that the concept of the ,morality of things' employed by a number of commentators is useful in summarizing the civilizing effects of material objects and addressing their sociological significance. From the sociology of consumption the idea of materiality as a sign of social relationships can be drawn, and from the sociology of technology the idea of socio-technical systems and actor-networks can contribute to the understanding of material civilization. It is argued that the concept of ,material capital' can usefully summarize the variable social value of objects but to understand the complexity of material civilization as it unfolds in everyday life, an analysis of ,material interaction' is needed. Finally the paper suggests some initial themes and issues apparent in contemporary society that the sociological study of material civilization might address; the increased volume, functional complexity and material specificity of objects and the increased social complexity, autonomy and substitutability that is entailed. A theory of ,material civilization' is the first step in establishing a sociology of objects. [source] Rapid Generation of Biologically Relevant Hydrogels Containing Long-Range Chemical GradientsADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Jiankang He Abstract Many biological processes are regulated by gradients of bioactive chemicals. Thus, the generation of materials with embedded chemical gradients may be beneficial for understanding biological phenomena and generating tissue-mimetic constructs. Here a simple and versatile method to rapidly generate materials containing centimeter-long gradients of chemical properties in a microfluidic channel is described. The formation of a chemical gradient is initiated by a passive-pump-induced forward flow and further developed during an evaporation-induced backward flow. The gradient is spatially controlled by the backward flow time and the hydrogel material containing the gradient is synthesized via photopolymerization. Gradients of a cell-adhesion ligand, Arg-Gly-Asp-Ser (RGDS), are incorporated in poly(ethylene glycol)-diacrylate (PEG-DA) hydrogels to test the response of endothelial cells. The cells attach and spread along the hydrogel material in a manner consistent with the RGDS-gradient profile. A hydrogel containing a PEG-DA concentration gradient and constant RGDS concentration is also shown. The morphology of cells cultured on such hydrogel changes from round in the lower PEG-DA concentration regions to well-spread in the higher PEG-DA concentration regions. This approach is expected to be a valuable tool to investigate the cell,material interactions in a simple and high-throughput manner and to design graded biomimetic materials for tissue engineering applications. [source] Combinatorial Polymer Scaffold Libraries for Screening Cell-Biomaterial Interactions in 3D,,ADVANCED MATERIALS, Issue 11 2008Yanyin Yang A combinatorial method for screening cell,biomaterial interactions in 3D is presented; polymeric, salt-leached scaffolds with varied composition and properties are present in a 96-well plate. Previous high-throughput approaches for screening cell,material interactions have focused on planar 2D surfaces or films. However, biomaterials are commonly used in a 3D scaffold format and cells behave more physiologically when cultured in 3D. [source] An ultrastructural study of cellular response to variation in porosity in phase-pure hydroxyapatiteJOURNAL OF MICROSCOPY, Issue 2 2004B. ANNAZ Summary Hydroxyapatite has been shown to be biocompatible and bioactive. Incorporation of porosity has been shown to enhance osteointegration; however, difficulty in controlling the extent and type of porosity has limited investigation into determining the role of both macro- and microporosity. The current investigation reports on the synthesis of four types of phase-pure hydroxyapatite with varying levels of porosity (HA1,HA4), and with defined levels of macro- and microporosities. Transmission electron microscopy was used to evaluate qualitatively the effect of these two parameters on cell,material interactions following a 30-day incubation period. Biological mineralization was observed within vesicles and the needle-like minerals were confirmed as hydroxyapatite using X-ray microanalysis. This demonstrated the suitability of primary human osteoblast-like cells as a tool to assess the extent of mineralization. Furthermore, internalization of hydroxyapatite particles was observed. Our findings show that the variation in macro- and microporosity does not affect the extent of cell,material interaction, with collagen synthesis evident in all samples. [source] The Dynamic Interaction of Water with Four Dental Impression Materials During CureJOURNAL OF PROSTHODONTICS, Issue 4 2009Dariush Hosseinpour PhD Abstract Purpose: The purpose of this work was to investigate the interaction of water with four different dental impression materials: Aquasil (Ultra XLV Type 3), Take 1 (Wash Regular Set), Genie (Light Body, Standard Set), and Impregum Garant (Soft Light Bodied Consistency). Materials and Methods: Apparent contact angles of de-ionized water made against thin horizontal sample films of the different materials under different conditions were measured from analysis of profile images of symmetrical sessile drops of water placed on the sample films using a Model FTÅ200 dynamic drop shape analysis system, which included a JAI M30 high speed CCD camera combined with a zoom microscope. Data were taken for specimens of dry ages (times following mixing) from a minimum of 20 seconds up to 1220 seconds. Imaging was started before the initial water/impression material contact, and lasted for at least 420 seconds in each case. The interval at the beginning of each run was 0.033 second, and then increased by a factor of 1.012 to the end. During the initial 3 seconds following the drop deposition, the drop's shape oscillated due to inertial effects, so apparent contact angle data during this period were neglected in all cases. All measurements were made at room temperature. The drops were enclosed in a humidified chamber that suppressed evaporation. All data were repeated at least five times, and results were analyzed where appropriate using one-way ANOVA. Microscopic images of the water/impression material interactions for fresh (uncured) materials were acquired to reveal the destructive interactions that resulted from such contact. Finally, surface tension measurements were made of water that had been contacted with material of varying dry age using the pendant drop method capability of the drop shape analysis system. These helped to assess the origin of hydrophilicity development for the different materials. Results: For short curing times (dry ages), water showed a destructive effect on the integrity of all of the impression materials, as evidenced by the formation of a crater beneath the water drop and a scum of material at its surface. These effects diminished with dry age until a critical curing time was reached, beyond which such destructive interactions were no longer detectable. These critical curing times were determined to be 80, 140, 110, and 185 seconds for Aquasil, Take 1, Genie, and Impregum, respectively. The initial contact angle following the respective critical curing time was lowest for Impregum, at 66°; while values for Aquasil, Genie, and Take 1 were 93°, 104°, and 110°, respectively. Beyond the critical curing times for the different materials, different degrees of hydrophilicity were observed. Aquasil showed the lowest final contact angle (<10°), with Impregum, Take 1, and Genie showing 31°, 34°, and 40°, respectively. Measurements of the surface tension of water after contact with the different materials suggested that for Aquasil, hydrophilicity appears to be developed through the leaching of surfactant from the material, whereas for Impregum, Take 1, and Genie, hydrophilicity is developed at least in part through a change in surface structure in contact with water. Impregum and Aquasil materials of dry ages well beyond the critical curing time exhibited a stick-slip behavior in their interline movement or contact angle evolution. This was believed to be due to the slowness in the leaching of surfactant (in the case of Aquasil) or the re-orientation of unleachable surface groups (in the case of the other materials) in comparison to the inherent kinetics of water drop spreading. Conclusions: All materials investigated in the fresh, uncured state showed qualitative decomposition when put in contact with water through the formation of a crater beneath the water drop and a scum of material at its surface. These effects diminished with curing time until beyond a critical value, no such effects were evident. The initial hydrophilicity of the materials as determined by the contact angles obtained at their respective critical dry ages was greatest for Impregum. Beyond the critical curing time, different degrees of hydrophilicity were observed, with Aquasil showing the lowest final contact angle. [source] Continuous supply of TGF,3 via adenoviral vector promotes type I collagen and viability of fibroblasts in alginate hydrogelJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 7 2010Yongchang Yao Abstract In recent years, transforming growth factor-,3 (TGF,3) has interested more and more researchers with its competence in engineered histogenesis. In the present study we employed recombinant adenoviral vectors to deliver the constitutively active TGF,3 gene to human dermal fibroblasts, which could maintain the continuous secretion of TGF,3 from the cells. The expression of type I collagen in the Ad-TGF,3 group increased significantly in comparison with other three groups: Neg (cells without treatment of the adenovirus), Ad-null (cells with treatment of the adenovirus, without the inserted gene) and Ad-shRNA (cells with treatment of the adenovirus encoding shRNA specific for type I collagen). Additionally, we demonstrated that TGF,3 enhanced the expression of Smad4 while inhibiting that of MMP-9, thus promoting the collagen transcription via the Smad signal transduction pathway and restraining collagen degradation by MMP-9, which contributed to the increasing type I collagen expression level. As type I collagen mediates cell,material interactions by providing anchorage, the viability of encapsulated fibroblasts in Ad-TGF,3 group was significantly higher than that in other three groups. Accordingly, this approach forms an effective way to improve the compatibility of non-adhesive hydrogels containing anchorage-dependent cells. Copyright © 2010 John Wiley & Sons, Ltd. [source] Aragonite crystalline matrix as an instructive microenvironment for neural developmentJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 8 2008H. Peretz Abstract The ability to mimic cell,matrix interactions in a way that closely resembles the natural environment is of a great importance for both basic neuroscience and for fabrication of potent scaffolding materials for nervous tissue engineering. Such scaffolding materials should not only facilitate cell attachment but also create a microenvironment that provides essential developmental and survival cues. We previously found that porous aragonite crystalline matrices of marine origin are an adequate and active biomaterial that promotes neural cell growth and tissue development. Here we studied the mechanism underlying these neural cell,material interactions, focusing on the three-dimensional (3D) surface architecture and matrix activity of these scaffolds. We introduced a new cloning technique of the hydrozoan Millepora dichotoma, through which calcein or 45Ca2+ were incorporated into the organism's growing skeleton and neuronal cells could then be cultured on the labelled matrices. Herein, we describe the role of matrix 3D architecture on neural cell type composition and survival in culture, and report for the first time on the capacity of neurons and astrocytes to exploit calcium ions from the supporting biomatrix. We found that hippocampal cells growing on the prelabelled aragonite lattice took up aragonite-derived Ca2+, and even enhanced this uptake when extracellular calcium ions were chelated by EGTA. When the aragonite-derived Ca2+ uptake was omitted by culturing the cells on coral skeletons coated with gold, cell survival was reduced but not arrested, suggesting a role for matrix architecture in neural survival. In addition, we found that the effects of scaffold architecture and chemistry on cell survival were more profound for neurons than for astrocytes. We submit that translocation of calcium from the biomaterial to the cells activates a variety of membrane-bound signalling molecules and leads to the subsequent cell behaviour. This kind of cell,material interaction possesses great potential for fabricating advanced biomaterials for neural tissue-engineering applications. Copyright © 2008 John Wiley & Sons, Ltd. [source] A finite element-based approach for whole-system simulation of packaging systems for their improved design and operationPACKAGING TECHNOLOGY AND SCIENCE, Issue 4 2009Ben James Hicks Abstract The introduction of legislation to minimize packaging waste requires consumer goods manufacturers to use lighter-weight materials and increase the use of recycled materials. This is demanding that machinery manufacturers provide highly flexible machines and tooling capable of handling these materials and new package designs. However, the ability of manufacturers to achieve this is all but prevented by a lack of fundamental understanding of machine,material interactions and an ability to generate such understanding. One way to overcome this is to use advanced simulation tools to represent the whole system including machine, process, materials and product. A finite element-based simulation has been created to represent the in-process behaviour of a packing system. The simulation focuses on the critical transition between flattened and erected states of a carton. In order to successfully simulate such a complex process, there are a number of major challenges concerning the representation of packaging materials and their properties, changing material behaviour during processing, machinery simulation and process modelling (simulating the interfacial interactions that take place during processing). The application of the whole-system simulation for the purposes of improved design and operation are discussed with respect to four activities: design and set-up of tooling, determination of optimal process settings, specification of material properties and the design of the pack. In all cases, a strong correlation was observed between the theoretical results and those obtained practically, thereby enabling quantitative understanding and quantitative rules to be generated. Copyright © 2009 John Wiley & Sons, Ltd. [source] Impact of environmental conditions on the performance of cartonboard skilletsPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2005C. Berry Abstract This paper discusses the importance of understanding machine,material interaction for achieving high process efficiencies. In the area of cartoning, the performance of cartonboard and hence the efficacy of the machine,material interactions can be significantly altered by changes in environmental conditions. In this paper, the process of carton conversion is dealt with and its performance during creasing, folding and subsequent erection is considered. An experimental programme was created to investigate the effect of moisture on the carton performance and in particular the important attribute of ,spring back'. The results of the experimental investigation are discussed with respect to the accepted understanding of the behaviour of cellulose structures. From this discussion, the implications for processing of cartonboard are identified and guidelines and considerations for storage and handling are proposed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Quantitative Analysis of Human Platelet Adhesions Under a Small-Scale Flow DeviceARTIFICIAL ORGANS, Issue 4 2010Katsuko S. Furukawa Abstract To realize real-time evaluation of human platelet adhesions onto material surfaces with small volumes of human platelet suspensions, we developed an apparatus consisting of a modified cone and plate-type viscometer, combined with an upright epi-fluorescence microscope. The apparatus allowed real-time evaluation of platelet,material interactions and the initial event of thrombus formation, using small platelet suspension volumes (7.5 µL) under shear flow conditions. To study the dynamic behavior of platelet,material interaction, we chose five representative opaque and transparent materials: acrylate resin (AC), polytetrafluoroethylene (PTFE), polyvynylchrolide (PVC), glass, and a monolayer of human normal umbilical cord vein endothelial cells (EC) on glass under shear flow conditions. The values of adhesiveness of human platelets to the test materials in descending order were as follows: AC > PTFE > PVC > glass > human EC. Under this new small-scale flow system, we could obtain highly reproducible data, which were comparable with results from a previously developed large-scale flow system. Therefore, the newly developed cone and plate-type rheometer is a useful instrument for testing and screening materials, and allows precise quantitative evaluation of human platelet adhesion. [source] Mapping the Interactions among Biomaterials, Adsorbed Proteins, and Human Embryonic Stem CellsADVANCED MATERIALS, Issue 27 2009Ying Mei An integrated high-throughput polymer synthesis and rapid material/protein/cell interaction assays were developed to optimize stem cell microenvironments. Microarrayed polymers were synthesized and studied for the ability to support the growth of partially differentiated human embryonic stem cells. In parallel, a programmed laser scanning cytometry system was developed to allow for rapid quantification of cell material interaction. [source] Calcium Phosphate-Based Resorbable Ceramics: Influence of MgO, ZnO, and SiO2 DopantsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2006Amit Bandyopadhyay Resorbable calcium phosphate (CaP)-based biomaterials are important because they can significantly improve health care by shortening the time necessary for restoration of functional loading of grafted bones. Although synthetic CaPs show exceptional similarities to natural bone, however, they are deficient in one major area, in that they do not have the same mineral content of bone. The focus of our work is to understand the influence of dopants on the physical, mechanical, and biological properties of tricalcium phosphate (TCP) resorbable ceramics with special emphasis toward in vitro strength degradation and cell,materials interactions as a function of time. For this purpose, ,-TCP was doped with magnesia (MgO), zinc oxide (ZnO), and silica (SiO2). Those dopants were added as individual dopants, and their binary and ternary compositions. It was found that these dopants significantly influenced densification behavior and as sintered microstructures of TCP. In vitro mineralization studies in simulated body fluids (SBF) for 12 weeks showed apatite growth on the highly porous compositions either on the surface or inside. From scanning electron microscopic analysis it was evident that surface degradation occurred on all compositions in SBF. Compression strengths for samples up to 12 weeks in SBF showed that it is possible to tailor strength loss behavior through compositional modifications. The highest compression strength was found for binary MgO,ZnO doped TCP. Overall, samples showed either a similar strength level during the 12 weeks test period, or a continuous decrease or a continuous increase in strength depending on dopant chemistry or amount. In vitro human osteoblast cell culture was used to determine influence of dopants on cell-materials interactions. All samples were non-toxic and biocompatible. Dopant chemistry also influenced adhesion, proliferation, and differentiation of osteoblastic precursor cell line 1 (OPC1) cells on these matrices. [source] | |||||||||||||