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To overcome the limiting antigenic repertoire of protein sub-units and the side effects of adjuvants applied in second generation vaccines, the present work combined in vitro and in vivo manipulations to develop biomaterials allowing... more
To overcome the limiting antigenic repertoire of protein sub-units and the side effects of adjuvants applied in second generation vaccines, the present work combined in vitro and in vivo manipulations to develop biomaterials allowing natural antigen-loading and presentation in vitro and further activation of the immune response in vivo. 3-dimensional laser micro-textured implantable Si-scaffolds supported mouse macrophage adherence, allowed natural seeding with human serum albumin (antigen) and specific antibody and inflammatory cytokine production in vitro. Implantation of Si-scaffolds loaded with antigen-activated macrophages induced an inflammatory reaction along with antigen-specific antibody production in vivo, which could be detected even 30 days post implantation. Analysis of implant histology using scanning electron microscopy showed that Si-scaffolds could be stable for a 6-month period. Such technology leads to personalized implantable vaccines, opening novel areas of rese...
Research Interests: Materials Science, Chemistry, Immune response, Cell Adhesion, Treatment Outcome, and 15 moreMacrophages, Medicine, Biological Sciences, SEM, In Vitro, Animals, Male, Cell Transplantation, In Vivo, Immune system, Antigens, Antigen, Macrophage activation, Medical and Health Sciences, and Tissue Scaffolds
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ABSTRACT The control of the outgrowth of neuronal cultured cells is of critical importance in a wide spectrum of neuroscience applications including tissue engineering scaffolds and neural electrodes. However, the study of neuron cell... more
ABSTRACT The control of the outgrowth of neuronal cultured cells is of critical importance in a wide spectrum of neuroscience applications including tissue engineering scaffolds and neural electrodes. However, the study of neuron cell outgrowth on more complex topographies remains limited. Phenotype alteration of stem cells and differentiated neuronal cells cultured on traditional flat substrates that lack structural cues, emphasize the necessity to shift from 2D to 3D cell culture models. The aim of the present study was to investigate the cellular response to topographical cues both at the micro and the nanoscale. In particular, we have previously reported that the artificial surfaces obtained by direct femtosecond laser texturing of solid surfaces in reactive gas atmosphere exhibit roughness at both micro- and nano-scales that mimics the hierarchical morphology of natural surfaces [1]. Variation of the laser fluence, alters the surface morphology, while the respective patterned substrates exhibit different roughness ratios and wettabilities. Cells with nerve cell phenotype were cultured on the substrates. Results on the culture of PC12 cells showed that the morphology of microspiked surfaces alone can be used for directional cytoskeletal rearrangement and subsequent differentiation into a neuronal phenotype. Besides this, the experiments with DRG/SCG nerve cells showed a good attachment, outgrowth and network formation and depending on the substrate morphology there was a differential orientation of the cells. In particular, cells were randomly oriented on low roughness surfaces, whereas there was a trend for parallel alignment on the intermediate and high roughness substrates. Our results indicate a method to tune cell responses by proper selection of the surface free energy of the substrate and may be promising for the design of cell culture platforms with controlled differentiation environment.
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ABSTRACT The ability to produce idealized cellular constructs is essential for understanding and controlling intercellular processes and ultimately for producing engineered tissue replacements. Preliminary results have been obtained on... more
ABSTRACT The ability to produce idealized cellular constructs is essential for understanding and controlling intercellular processes and ultimately for producing engineered tissue replacements. Preliminary results have been obtained on collagen modification by irradiation with single and multiple pulses of femtosecond laser with variable pulse duration. Irradiation of collagen thin film by single pulses of femtosecond duration results in creation of foam layer with micrometer thickness. The structure and thickness of the layer strongly depends on the number of the applied laser pulses. The surface properties of collagen thin films before and after Ti-sapphire irradiation with 800 nm were investigated by means of the technique Field Emission Scanning Electron Microscope (FESEM). Based on the FESEM results, it was possible to identify an energy density range as the ablation threshold for collagen thin films. The laser-induced foam formation was characterized over the intensity range 3 - 4.2x1011 W/cm2. The results of the field emission scanning electron microscopy, showed that by tailoring the laser pulse duration, improved the uniformity of the pore network. Examination of the interaction of ultra-short laser pulses with collagen films is useful for controlling the chemical and microstructural modification of the created foam layer.
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... V. Melissinaki1, AA Gill2, I. Ortega2, M. Vamvakaki1, A. Ranella1, C. Fotakis1, M. Farsari1*, and F. Claeyssens2. 1Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH), N. Plastira... more
... V. Melissinaki1, AA Gill2, I. Ortega2, M. Vamvakaki1, A. Ranella1, C. Fotakis1, M. Farsari1*, and F. Claeyssens2. 1Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH), N. Plastira 100, 70013, Heraklion, Crete, Greece. ...
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THE IDENTIFICATION of HLA-G on placental cytotrophoblast cells opened new insights in defining the initial trigger by which the maternal immune system recognizes the fetal allograft and emits growth signals to the feto-placental unit. The... more
THE IDENTIFICATION of HLA-G on placental cytotrophoblast cells opened new insights in defining the initial trigger by which the maternal immune system recognizes the fetal allograft and emits growth signals to the feto-placental unit. The presence of an alternatively spliced mRNA giving rise to secreted HLA-G class I antigens makes these molecules very important candidates for explaining peripheral maternal immunostimulation and immunosuppression during pregnancy. In many cases, especially during transplantation, soluble MHC antigens have been shown to exert immunosuppressive activity. Therefore, during pregnancy, the maternal organism is expected to respond to the semior fully allogeneic fetus in a similar way, where soluble antigens during the first 2 months of gestation elaborate messages that are positive to fetal growth (immunostimulation) and thereafter, equilibrates fetal development by inducing specific immunosuppression. Disability of the maternal organism to elaborate these two types of reaction results in embryo loss, mainly during the first trimester of pregnancy, which in previous studies has been correlated with expression of class II MHC antigens on trophoblasts, normally absent from these cells throughout pregnancy. In the present study, using the monomorphic W6/32 and 7H3 antibodies, we define the levels of soluble HLA-G and HLA-DR respectively in the serum of healthy women before, during, and after pregnancy and compare them to cases of first-trimester fetal abortions of unknown etiology. Taking into consideration the obtained results, along with similar findings from animal experimental abortion models, we conclude that the levels of soluble class I/II in the maternal serum can be predictive to a successful pregnancy outcome.
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Research Interests: Endocrinology, Enzyme Inhibitors, Medicine, Biological Sciences, Lipopolysaccharide, and 15 moreCell line, Internal Medicine, Escherichia coli, Mice, Nitric oxide, Female, Animals, CHEMICAL SCIENCES, Lipopolysaccharides, Nitric Oxide Synthase, Fetus, Guanidines, Interleukin, Interferon gamma, and Medical and Health Sciences
Research Interests: Materials Science, Chemistry, Self Assembly, Crystallization, Nanowire, and 15 moreNanotechnology, Medicine, Multidisciplinary, Adsorption, Nanostructures, Fabrication, Nanostructure, Peptides, Particle Size, Surface Properties, Three Dimensional, Molecular Conformation, Materials Testing, Protein Binding, and binding sites
Disturbance of the cytokine equilibrium has been accused for many pathological disorders. Microbial infections, autoimmune diseases, graft rejection have been correlated to over- or under-production of specific cytokines which are... more
Disturbance of the cytokine equilibrium has been accused for many pathological disorders. Microbial infections, autoimmune diseases, graft rejection have been correlated to over- or under-production of specific cytokines which are produced as responder molecules to the various immune stimuli. The sole naturally occurring immune reaction in the organism is developed during the gestational period where, despite the presence of a semi-allogeneic graft, maternal immunoreactivity is driven to support fetal growth. The successful embryo development has been attributed to the important intervention of cytokines where some have been characterized as indispensable and others deleterious to fetal growth. However, the physiological levels of many factors during the gestational process have not been determined. Thus, in the present study we have measured and established the values of IL-1α, IL-2, IL-3, IL-4, IL-6, IL-10, IL-12, GM-CSF, TNF- α and IFN-γ during all phases of human pregnancy (firs...
Research Interests: Immunology, Cytokines, Medicine, Abortion, Pregnancy, and 7 moreHumans, Female, Cytokine, Immune system, Fetus, Gestation, and Pathological
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Research Interests: Structural Biology, Biology, Cell Biology, Confocal Microscopy, Medicine, and 15 moreCell Division, Structural, Embryo, Mice, Animals, In Vitro Fertilization, FRET, SHG, Embryonic Development, Body Patterning, Fertilization in Vitro, Polar Body, Embryos, Biochemistry and cell biology, and Cleavage furrow
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Research Interests: Immunology, Biology, Macrophages, Confocal Microscopy, Medicine, and 15 moreCell Culture, Cell line, Humans, Mice, Female, Animals, Antigen Presentation, Fluorescent Antibody Technique, Human Immunology, Cytoplasm, Antigen, Antigen presenting cells, Interferon gamma, Cell Membrane, and Human leukocyte antigen
Research Interests: Materials Science, Microfluidics, Laser, Cell Adhesion, Femtosecond Laser, and 15 moreNanotechnology, Surface Engineering, Medicine, Surface Chemistry, Cell Culture, Biomicrofluidics, Organic Semiconductor Laser, Surface modification, Classical Physics, Interdisciplinary Engineering, Materials Processing, Surface Energy, Nanostructured Material, D structure, and Electric Field
Research Interests: Materials Engineering, Chemistry, Biomedical Engineering, Laser, Fluorescence, and 15 moreFemtosecond Laser, Medicine, Protein Kinases, Lasers, Spectrophotometry, Laser Induced Fluorescence, Enzyme, Femtosecond, Surface Properties, Biomolecule, Microchemistry, Biological activity, Enzymatic Activity, Biological Assay, and Titin
The aim of this study is to investigate fibroblast cell adhesion and viability on highly rough three-dimensional (3D) silicon (Si) surfaces with gradient roughness ratios and wettabilities. Culture surfaces were produced by femtosecond... more
The aim of this study is to investigate fibroblast cell adhesion and viability on highly rough three-dimensional (3D) silicon (Si) surfaces with gradient roughness ratios and wettabilities. Culture surfaces were produced by femtosecond (fs) laser structuring of Si wafers and comprised forests of conical spikes exhibiting controlled dual-scale roughness at both the micro- and the nano-scale. Variable roughness could be achieved by changing the laser pulse fluence and control over wettability and therefore surface energy could be obtained by covering the structures with various conformal coatings, which altered the surface chemistry without, however, affecting morphology. The results showed that optimal cell adhesion was obtained for small roughness ratios, independently of the surface wettability and chemistry, indicating a non-monotonic dependence of fibroblast adhesion on surface energy. Additionally, it was shown that, for the same degree of roughness, a proper change in surface energy could switch the behaviour from cell-phobic to cell-philic and vice versa, transition that was always correlated to surface wettability. These experimental findings are discussed on the basis of previous theoretical models describing the relation of cell response to surface energy. The potential use of the patterned Si substrates as model scaffolds for the systematic exploration of the role of 3D micro/nano morphology and/or surface energy on cell adhesion and growth is envisaged.
Research Interests: Materials Science, Cell Adhesion, Scanning Electron Microscopy, Silicon, Nanotechnology, and 15 moreConfocal Microscopy, Medicine, Multidisciplinary, Adhesion, Surface Chemistry, Surface Roughness, Mice, Animals, Composite Material, T cells, Particle Size, Surface Properties, Surface Energy, Theoretical Model, and Surface Finish
ABSTRACT Materials processing by ultrafast lasers offers several attractive possibilities for micro/nano fabrication applications. Several exciting prospects arise in the context of surface and bulk laser induced modifications. These form... more
ABSTRACT Materials processing by ultrafast lasers offers several attractive possibilities for micro/nano fabrication applications. Several exciting prospects arise in the context of surface and bulk laser induced modifications. These form the basis for diverse applications, including the development and functionalization of laser engineered surfaces, the laser transfer of biomolecules and the functionalization of 3D structures constructed by multiphoton stereolithography. In particular, two examples will be discussed in the ...
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Cancer cure schemes are based on accurate diagnosis and treatment protocols that could have minimal side-effects for a patient. For this purpose the scientific community seeks cost-efficient advanced materials that serve the combined role... more
Cancer cure schemes are based on accurate diagnosis and treatment protocols that could have minimal side-effects for a patient. For this purpose the scientific community seeks cost-efficient advanced materials that serve the combined role of diagnosis and therapy. However, it is imperative that a so-called theranostic material is characterised in depth for its physical, chemical and biocompatibility properties. In order to address this challenge, we have developed size-controlled (50-100 nm), water-dispersible clusters of maghemite nanoparticles (NPs), named Colloidal Nanoclusters (CNCs). Characterization techniques (including, HRTEM, X-ray scattering, Mössbauer spectroscopy, SQUID magnetometry), combined with theoretical Monte Carlo simulations have probed the microscopic mechanisms that govern the growth and magnetic behaviour of these CNCs. We have found that such controlled nanoparticle assemblies, display collective magnetic behaviour as an outcome of the intra-cluster dipolar ...
Abstract Peptide-based arrays and patterns are a powerful tool in the study of protein functionality, with a variety of applications such as the study of interactions between peptides and enzymes, proteins and DNA. One of the main and... more
Abstract Peptide-based arrays and patterns are a powerful tool in the study of protein functionality, with a variety of applications such as the study of interactions between peptides and enzymes, proteins and DNA. One of the main and most critical issues is the generation of high density arrays which maintain the biological function of the peptides. In this study, we employ Laser-Induced Forward Transfer for the generation of high density photosensitive biotin arrays on ORMOCER®-coated surfaces. We then generate peptide microarrays, ...
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1H-NMR relaxometric experiments over an extended frequency range show that ferrimagnetic colloidal nanoclusters exhibit enhanced transverse relaxivity, r2.
Research Interests: Physics, Materials Science, Inorganic Chemistry, Magnetic Resonance Imaging, Nanoparticles, and 15 moreMagnetic Resonance Spectroscopy, Medicine, Magnetic nanoparticles, Mice, Animals, Colloids, Particle Size, Magnetic Nanoparticles, Cell Proliferation, Colloid, Cell Survival, Ferric Compounds, Nanocrystal, maghemite, and Cell culture techniques
The construction of the ideal three-dimensional scaffold for cell culture is one of the most intriguing topics in tissue engineering. It has been shown that cells can be cultured on most organic biomimetic materials, which now are losing... more
The construction of the ideal three-dimensional scaffold for cell culture is one of the most intriguing topics in tissue engineering. It has been shown that cells can be cultured on most organic biomimetic materials, which now are losing popularity in favour of novel, hybrid systems. In this study, a series of photosensitive sol-gel hybrid materials, based on silicon-zirconium and silicon-titanium oxides, have been investigated for their suitability in three-dimensional scaffold fabrication. These materials can be structured by two-photon polymerization, a laser-based technique allowing the fabrication of micrometre-size structures with submicron resolution. The work presented here examined the effect of the organic/inorganic composition of the materials on cell behaviour and the establishment of a 'cell-culture friendly' environment. This is vital for cell adhesion, growth and differentiation, as the organic part of the material provides the soft matrix for cell growth, whereas the inorganic component gives the mechanical stability and rigidity of the three-dimensional structures. In addition, the use of femtosecond laser structuring permits the fabrication of a wide range of mechanically stable scaffolds of different sizes and shapes to be tested in terms of cell viability, proliferation and orientation.
Research Interests: Materials Science, Biomedical Engineering, Cell Adhesion, Femtosecond Laser, Nanotechnology, and 15 moreMedicine, Cell Culture, Cell Differentiation, Biomedical Materials, Medical Biotechnology, Mice, Animals, Fabrication, Cell Viability, Materials Testing, Biocompatible Materials, Cell Survival, Cell Growth, Hybrid System, and Cell culture techniques
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Research Interests: Materials Science, Fluorescence Microscopy, Cell Adhesion, Nanotechnology, Medicine, and 15 moreAdhesion, Cell Culture, Cell line, Lasers, Mice, Animals, Nanostructures, Biofabrication, Microstructures, Polydimethylsiloxane, Elastic Modulus, Human Fibroblasts, Lactic Acid, Cell Survival, and fibroblasts
ABSTRACT Research on magnetic nanocrystals attracts wide-spread interest because of their challenging fundamental properties, but it is also driven by problems of practical importance to the society, ranging from electronics (e.g.... more
ABSTRACT Research on magnetic nanocrystals attracts wide-spread interest because of their challenging fundamental properties, but it is also driven by problems of practical importance to the society, ranging from electronics (e.g. magnetic recording) to biomedicine. In that respect, iron oxides are model functional materials as they adopt a variety of oxidation states and coordinations that facilitate their use. We show that a promising way to engineer further their technological potential in diagnosis and therapy is the assembly of primary nanocrystals into larger colloidal entities, possibly with increased structural complexity. In this context, elevated-temperature nanochemistry (c.f. based on a polyol approach) permitted us to develop size-tunable, low-cytotoxicity iron-oxide nanoclusters, entailing iso-oriented nanocrystals, with enhanced magnetization. Experimental (magnetometry, electron microscopy, Mössbauer and NMR spectroscopies) results supported by Monte Carlo simulations are reviewed to show that such assemblies of surface-functionalized iron oxide nanocrystals have a strong potential for innovation. The clusters’ optimized magnetic anisotropy (including microscopic surface spin disorder) and weak ferrimagnetism at room temperature, while they do not undermine colloidal stability, endow them a profound advantage as efficient MRI contrast agents and hyperthermic mediators with important biomedical potential.
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ABSTRACT Materials processing by ultrafast lasers offers several attractive possibilities for micro/nano fabrication applications. Several exciting prospects arise in the context of surface and bulk laser induced modifications. These form... more
ABSTRACT Materials processing by ultrafast lasers offers several attractive possibilities for micro/nano fabrication applications. Several exciting prospects arise in the context of surface and bulk laser induced modifications. These form the basis for diverse applications, including the development and functionalization of laser engineered surfaces, the laser transfer of biomolecules and the functionalization of 3D structures constructed by multiphoton stereolithography.
Patterning of neuronal outgrowth in vitro is important in tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. To date, this has been achieved with the aid of micro-and nanofabrication... more
Patterning of neuronal outgrowth in vitro is important in tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. To date, this has been achieved with the aid of micro-and nanofabrication techniques giving rise to various anisotropic topographies, either in the form of continuous or discontinuous structures. In this study we propose a currently unexplored geometry of a 3D culture substrate for neuronal cell growth comprising discontinuous subcellular micro-structures with anisotropic geometrical cross-section. Specifically, using laser precision 3D micro/nano fabrication techniques, silicon substrates comprising arrays of parallel oriented elliptical microcones (MCs) were fabricated to investigate whether a discontinuous geometry comprising anisotropic features at the subcellular level could influence the alignment of peripheral nervous system cell populations. It was shown that both Schwann cells and axons of sympathetic neurons were parallel oriented onto the MCs of elliptical shape, while they exhibited a random orientation onto the MCs of arbitrary shape. Notably, this topography-induced guidance effect was also observed in more complex cell culture systems , such as the organotypic culture whole dorsal root ganglia (DRG) explants. Our results suggest that a discontinuous topographical pattern could promote Schwann cell and axonal alignment, provided that it hosts anisotropic geometrical features, even though the sizes of those range at the subcellular length-scale. The laser-patterned arrays of MCs presented here could potentially be a useful platform for patterning neurons into artificial networks, allowing the study of neuronal cells interactions under 3D ex-vivo conditions.
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Research Interests: Inorganic Chemistry, Magnetic Resonance Imaging, Nanoparticles, Transmission Electron Microscopy, Magnetic Resonance Spectroscopy, and 10 moreMagnetic nanoparticles, Mice, Animals, Colloids, Particle Size, Surface Properties, Magnetic Nanoparticles, Cell Proliferation, Cell Survival, and Ferric Compounds
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Laser-induced forward transfer has been used for the deposition of photoactive biotin in micron-scale patterns. The process uses a 500fs pulsed KrF laser beam to transfer small amounts of a liquid solution target as micron-size droplets... more
Laser-induced forward transfer has been used for the deposition of photoactive biotin in micron-scale patterns. The process uses a 500fs pulsed KrF laser beam to transfer small amounts of a liquid solution target as micron-size droplets to a substrate placed parallel and in close proximity to it. The biomolecules remain active after the transfer; this is demonstrated through fluorescence assays. In addition to the laser parameters, those regarding the target composition and the receiving surface for the miniaturization of the ...
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ABSTRACT Research on magnetic nanocrystals attracts wide-spread interest because of their challenging fundamental properties, but it is also driven by problems of practical importance to the society, ranging from electronics (e.g.... more
ABSTRACT Research on magnetic nanocrystals attracts wide-spread interest because of their challenging fundamental properties, but it is also driven by problems of practical importance to the society, ranging from electronics (e.g. magnetic recording) to biomedicine. In that respect, iron oxides are model functional materials as they adopt a variety of oxidation states and coordinations that facilitate their use. We show that a promising way to engineer further their technological potential in diagnosis and therapy is the assembly of primary nanocrystals into larger colloidal entities, possibly with increased structural complexity. In this context, elevated-temperature nanochemistry (c.f. based on a polyol approach) permitted us to develop size-tunable, low-cytotoxicity iron-oxide nanoclusters, entailing iso-oriented nanocrystals, with enhanced magnetization. Experimental (magnetometry, electron microscopy, Mössbauer and NMR spectroscopies) results supported by Monte Carlo simulations are reviewed to show that such assemblies of surface-functionalized iron oxide nanocrystals have a strong potential for innovation. The clusters’ optimized magnetic anisotropy (including microscopic surface spin disorder) and weak ferrimagnetism at room temperature, while they do not undermine colloidal stability, endow them a profound advantage as efficient MRI contrast agents and hyperthermic mediators with important biomedical potential.