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Sarkar AS, Konidakis I, Gagaoudakis E, Maragkakis GM, Psilodimitrakopoulos S, Katerinopoulou D, Sygellou L, Deligeorgis G, Binas V, Oikonomou IM, Komninou P, Kiriakidis G, Kioseoglou G, Stratakis E. Liquid Phase Isolation of SnS Monolayers with Enhanced Optoelectronic Properties. Adv Sci (Weinh) 2023; 10:e2201842. [PMID: 36574469 PMCID: PMC9951343 DOI: 10.1002/advs.202201842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/20/2022] [Indexed: 06/17/2023]
Abstract
Recent advances in atomically thin two dimensional (2D) anisotropic group IVA -VI metal monochalcogenides (MMCs) and their fascinating intrinsic properties and potential applications are hampered due to an ongoing challenge of monolayer isolation. Among the most promising MMCs, tin (II) sulfide (SnS) is an earth-abundant layered material with tunable bandgap and anisotropic physical properties, which render it extraordinary for electronics and optoelectronics. To date, however, the successful isolation of atomically thin SnS single layers at large quantities has been challenging due to the presence of strong interlayer interactions, attributed to the lone-pair electrons of sulfur. Here, a novel liquid phase exfoliation approach is reported, which enables the overcome of such strong interlayer binding energy. Specifically, it demonstrates that the synergistic action of external thermal energy with the ultrasound energy-induced hydrodynamic force in solution gives rise to the systematic isolation of highly crystalline SnS monolayers (1L-SnS). It is shown that the exfoliated 1L-SnS crystals exhibit high carrier mobility and deep-UV spectral photodetection, featuring a fast carrier response time of 400 ms. At the same time, monolayer-based SnS transistor devices fabricated from solution present a high on/off ratio, complemented with a responsivity of 6.7 × 10-3 A W-1 and remarkable stability upon prolonged operation in ambient conditions. This study opens a new avenue for large-scale isolation of highly crystalline SnS and other MMC manolayers for a wide range of applications, including extended area nanoelectronic devices, printed from solution.
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Affiliation(s)
- Abdus Salam Sarkar
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
| | - Ioannis Konidakis
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
| | - E. Gagaoudakis
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
| | - G. M. Maragkakis
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
- Department of PhysicsUniversity of CreteHeraklion710 03Greece
| | - S. Psilodimitrakopoulos
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
| | - D. Katerinopoulou
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
- Department of PhysicsUniversity of CreteHeraklion710 03Greece
| | - L. Sygellou
- Institute of Chemical Engineering Sciences (ICE‐HT)Foundation of Research and TechnologyHellas, P.O. Box 1414Rio Patras26504Greece
| | - G. Deligeorgis
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
| | - Vassilios Binas
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
- Department of PhysicsUniversity of CreteHeraklion710 03Greece
| | - Ilias M. Oikonomou
- Department of PhysicsAristotle University of ThessalonikiThessaloniki54124Greece
| | - Philomela Komninou
- Department of PhysicsAristotle University of ThessalonikiThessaloniki54124Greece
| | - G. Kiriakidis
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
| | - G. Kioseoglou
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
- Department of Materials Science and TechnologyUniversity of CreteHeraklion710 03Greece
| | - E. Stratakis
- Institute of Electronic Structure and LaserFoundation for Research and Technology‐HellasHeraklion700 13Greece
- Department of PhysicsUniversity of CreteHeraklion710 03Greece
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2
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Konidakis I, Karagiannaki A, Stratakis E. Advanced composite glasses with metallic, perovskite, and two-dimensional nanocrystals for optoelectronic and photonic applications. Nanoscale 2022; 14:2966-2989. [PMID: 35142770 DOI: 10.1039/d1nr07711b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This article reviews the tremendous advancement of the optoelectronic and photonic properties of inorganic oxide glasses upon the incorporation of metallic, perovskite, and two-dimensional nanocrystals within their matrix. In the first part, we present the exploitation of typical inorganic oxide glasses as hosting platforms for the incorporation of metallic nanoparticles. Such a method offers tremendous advantages in terms of inducing plasmonic features that enable the tunability of the photonic properties of the embedded materials. Along similar lines, due to their exceptional photoluminescence properties all inorganic lead halide perovskites show enormous potential for next generation light-emitting, optoelectronic and photonic devices. To date, however, their usage is limited significantly by their poor chemical stability upon exposure to moisture, and lead toxicity issues. A recent and highly promising approach for overcoming these important challenges is the encapsulation of perovskite nanocrystals within inorganic oxide glasses. Based on this, in the second section we focus on the recent advancements in perovskite glasses in terms of the developed fabrication procedures and the resulting optoelectronic features, while considering the production limitations. In the last part, we consider the development of composite two-dimensional materials glass architectures in terms of the available synthesis routes and the novelty of their optical and emission features. Finally, future perspectives on the described composite glass systems in terms of potential applications are summarized.
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Affiliation(s)
- I Konidakis
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 70013 Heraklion-Crete, Greece.
| | - A Karagiannaki
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 70013 Heraklion-Crete, Greece.
| | - E Stratakis
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 70013 Heraklion-Crete, Greece.
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3
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Chukova O, Nedilko SA, Nedilko SG, Voitenko T, Androulidaki M, Manousaki A, Papadopoulos A, Savva K, Stratakis E. Pulsed laser deposition of the LaVO4:Eu, Ca nanoparticles on glass and silicon substrates. Appl Nanosci 2020. [DOI: 10.1007/s13204-020-01503-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Angelaki D, Kavatzikidou P, Fotakis C, Stratakis E, Ranella A. Laser-induced topographies enable the spatial patterning of co-cultured peripheral nervous system cells. Mater Sci Eng C Mater Biol Appl 2020; 115:111144. [PMID: 32600731 DOI: 10.1016/j.msec.2020.111144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/20/2020] [Accepted: 05/29/2020] [Indexed: 12/15/2022]
Abstract
The peripheral nervous system comprises glia and neurons that receive the necessary cues for their adhesion and proliferation from their extracellular milieu. In this study, a spatial platform of pseudoperiodic morphologies including patterns of nano- and micro- structures on Si were developed via direct ultrafast-laser structuring and were used as substrates for the patterning of co-cultured neuronal cells. The response of murine Schwann (SW10) and Neuro2a (N2a) cells were investigated both in monocultures and in a glia and neuronal co-culture system. Our results denoted that different types of neural tissue cells respond differently to the underlying topography, but furthermore, the presence of the glial cells alters the adhesion behavior of the neuronal cells in their co-culture. Therefore, we envisage that direct laser structuring that enables spatial patterning of the cells of the nervous system in a controllable manner according to the research needs, could in the future be a useful tool for understanding neural network interfaces and their electrical activity, synaptic processes and myelin formation.
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Affiliation(s)
- D Angelaki
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), Heraklion 711 10, Greece; Department of Physics, University of Crete, Heraklion 710 03, Greece.
| | - P Kavatzikidou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), Heraklion 711 10, Greece.
| | - C Fotakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), Heraklion 711 10, Greece; Department of Physics, University of Crete, Heraklion 710 03, Greece.
| | - E Stratakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), Heraklion 711 10, Greece; Department of Physics, University of Crete, Heraklion 710 03, Greece.
| | - A Ranella
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), Heraklion 711 10, Greece.
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Papadimitriou L, Manganas P, Ranella A, Stratakis E. Biofabrication for neural tissue engineering applications. Mater Today Bio 2020; 6:100043. [PMID: 32190832 PMCID: PMC7068131 DOI: 10.1016/j.mtbio.2020.100043] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 12/28/2022] Open
Abstract
Unlike other tissue types, the nervous tissue extends to a wide and complex environment that provides a plurality of different biochemical and topological stimuli, which in turn defines the advanced functions of that tissue. As a consequence of such complexity, the traditional transplantation therapeutic methods are quite ineffective; therefore, the restoration of peripheral and central nervous system injuries has been a continuous scientific challenge. Tissue engineering and regenerative medicine in the nervous system have provided new alternative medical approaches. These methods use external biomaterial supports, known as scaffolds, to create platforms for the cells to migrate to the injury site and repair the tissue. The challenge in neural tissue engineering (NTE) remains the fabrication of scaffolds with precisely controlled, tunable topography, biochemical cues, and surface energy, capable of directing and controlling the function of neuronal cells toward the recovery from neurological disorders and injuries. At the same time, it has been shown that NTE provides the potential to model neurological diseases in vitro, mainly via lab-on-a-chip systems, especially in cases for which it is difficult to obtain suitable animal models. As a consequence of the intense research activity in the field, a variety of synthetic approaches and 3D fabrication methods have been developed for the fabrication of NTE scaffolds, including soft lithography and self-assembly, as well as subtractive (top-down) and additive (bottom-up) manufacturing. This article aims at reviewing the existing research effort in the rapidly growing field related to the development of biomaterial scaffolds and lab-on-a-chip systems for NTE applications. Besides presenting recent advances achieved by NTE strategies, this work also delineates existing limitations and highlights emerging possibilities and future prospects in this field.
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Affiliation(s)
- L. Papadimitriou
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, 71003, Greece
| | - P. Manganas
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, 71003, Greece
| | - A. Ranella
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, 71003, Greece
| | - E. Stratakis
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, 71003, Greece
- Physics Department, University of Crete, Heraklion, 71003, Crete, Greece
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6
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Brintakis K, Gagaoudakis E, Kostopoulou A, Faka V, Argyrou A, Binas V, Kiriakidis G, Stratakis E. Ligand-free all-inorganic metal halide nanocubes for fast, ultra-sensitive and self-powered ozone sensors. Nanoscale Adv 2019; 1:2699-2706. [PMID: 36132711 PMCID: PMC9419230 DOI: 10.1039/c9na00219g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 05/22/2019] [Indexed: 05/30/2023]
Abstract
Ligand-free all-inorganic lead halide nanocubes have been investigated as ozone sensing materials operating at room temperature. It is found that the nanocubes, crystallined in the orthorhombic CsPbBr3 structure, can operate at room temperature, be self-powered and exhibit high sensitivity and remarkable repeatability. More importantly, they demonstrate higher sensitivity (54% in 187 ppb) and faster response and recovery times compared to hybrid lead mixed halide perovskite (CH3NH3PbI3-x Cl x ) layers, which is the only lead halide perovskite material tested for ozone sensing, to date. Following the exposure to an ozone environment, the stoichiometry and the morphology of the nanocubes remain unaltered. The facile and easy fabrication process together with the high responsivity and stability to the ozone environment makes the bare CsPbBr3 nanocubes a promising material for sensing applications. The sensing properties of the nanoparticulate metal halides presented here provide new exciting opportunities towards engineering reliable and cheap sensing elements for room-temperature operated and self-powered sensors.
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Affiliation(s)
- K Brintakis
- Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas P.O. Box 1385 Heraklion 70013 Crete Greece
| | - E Gagaoudakis
- Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas P.O. Box 1385 Heraklion 70013 Crete Greece
- University of Crete, Department of Physics 710 03 Heraklion Crete Greece
| | - A Kostopoulou
- Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas P.O. Box 1385 Heraklion 70013 Crete Greece
| | - V Faka
- Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas P.O. Box 1385 Heraklion 70013 Crete Greece
- University of Crete, Department of Physics 710 03 Heraklion Crete Greece
- University of Crete, Department of Materials Science and Technology 710 03 Heraklion Crete Greece
| | - A Argyrou
- Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas P.O. Box 1385 Heraklion 70013 Crete Greece
- University of Crete, Department of Materials Science and Technology 710 03 Heraklion Crete Greece
| | - V Binas
- Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas P.O. Box 1385 Heraklion 70013 Crete Greece
- University of Crete, Department of Physics 710 03 Heraklion Crete Greece
- Crete Center for Quantum Complexity and Nanotechnology, Department of Physics, University of Crete 71003 Heraklion Greece
| | - G Kiriakidis
- Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas P.O. Box 1385 Heraklion 70013 Crete Greece
- University of Crete, Department of Physics 710 03 Heraklion Crete Greece
| | - E Stratakis
- Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas P.O. Box 1385 Heraklion 70013 Crete Greece
- University of Crete, Department of Physics 710 03 Heraklion Crete Greece
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Kostopoulou A, Vernardou D, Savva K, Stratakis E. All-inorganic lead halide perovskite nanohexagons for high performance air-stable lithium batteries. Nanoscale 2019; 11:882-889. [PMID: 30608506 DOI: 10.1039/c8nr10009h] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
All-inorganic Cs4PbBr6 perovskite nanohexagons, pre-synthesized by a room temperature co-precipitation method, have been electrochemically investigated in a conventional aqueous electrolyte for potential application as an anode material in Li-ion batteries. The nanohexagons were uniformly deposited on ITO precoated glass substrate and subsequently annealed at ambient air to form a mechanically stable perovskite layer. These perovskite layers showed excellent performance during continuous Li-ion intercalation/deintercalation scans in an aqueous electrolyte, exhibiting a diffusion coefficient of 7.34 × 10-8 cm2 s-1, a specific discharge capacity of 377 mA h g-1, a capacity retention of 75% and coulombic efficiency that deteriorated to 98% after 100 scans. A water-triggered transformation of the Cs4PbBr6 to the CsPb2Br5 was initially observed followed by a reversible Li intercalation/deintercalation in the CsPb2Br5 structure for 40 consecutive scans. Following this period, an irreversible conversion reaction of CsPb2Br5 to CsBr and PbBr2 took place. The excellent electrochemical performance observed is promising towards the potential application of all-inorganic perovskite nanocrystals for air-stable, lithium storage applications.
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Affiliation(s)
- A Kostopoulou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, 71110 Crete, Greece.
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8
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Kostopoulou A, Sygletou M, Brintakis K, Lappas A, Stratakis E. Low-temperature benchtop-synthesis of all-inorganic perovskite nanowires. Nanoscale 2017; 9:18202-18207. [PMID: 29159334 DOI: 10.1039/c7nr06404g] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A facile, low-temperature precipitation-based method is utilized for the synthesis of ultra-thin and highly uniform cesium lead bromide perovskite nanowires (NWs). The reactions facilitate the NWs' crystalline nature over micron-size lengths, while they impart tailored nanowire widths that range from the quantum confinement regime (∼7 nm) down to 2.6 nm. This colloidal synthesis approach is the first of its kind that is carried out on the work-bench, without demanding chemical synthesis equipment. Importantly, the NWs' photoluminescence is shown to improve over time, with no requirement for tedious post-synthesis surface treatment.
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Affiliation(s)
- A Kostopoulou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Vassilika Vouton, Heraklion, 71110, Crete, Greece.
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Yiannakou C, Simitzi C, Manousaki A, Fotakis C, Ranella A, Stratakis E. Cell patterning via laser micro/nano structured silicon surfaces. Biofabrication 2017; 9:025024. [PMID: 28485302 DOI: 10.1088/1758-5090/aa71c6] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The surface topography of biomaterials can have an important impact on cellular adhesion, growth and proliferation. Apart from the overall roughness, the detailed morphological features, at all length scales, significantly affect the cell-biomaterial interactions in a plethora of applications including structural implants, tissue engineering scaffolds and biosensors. In this study, we present a simple, one-step direct laser patterning technique to fabricate nanoripples and dual-rough hierarchical micro/nano structures to control SW10 cell attachment and migration. It is shown that, depending on the laser processing conditions, distinct cell-philic or cell-repellant patterned areas can be attained with a desired motif. We envisage that our technique could enable spatial patterning of cells in a controllable manner, giving rise to advanced capabilities in cell biology research.
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Affiliation(s)
- Ch Yiannakou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion, 71110, Crete, Greece. Department of Physics, University of Crete, Heraklion, 71003, Crete, Greece
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10
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Simitzi C, Ranella A, Stratakis E. Controlling the morphology and outgrowth of nerve and neuroglial cells: The effect of surface topography. Acta Biomater 2017; 51:21-52. [PMID: 28069509 DOI: 10.1016/j.actbio.2017.01.023] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 12/23/2016] [Accepted: 01/05/2017] [Indexed: 02/07/2023]
Abstract
Unlike other tissue types, like epithelial tissue, which consist of cells with a much more homogeneous structure and function, the nervous tissue spans in a complex multilayer environment whose topographical features display a large spectrum of morphologies and size scales. Traditional cell cultures, which are based on two-dimensional cell-adhesive culture dishes or coverslips, are lacking topographical cues and mainly simulate the biochemical microenvironment of the cells. With the emergence of micro- and nano-fabrication techniques new types of cell culture platforms are developed, where the effect of various topographical cues on cellular morphology, proliferation and differentiation can be studied. Different approaches (regarding the material, fabrication technique, topographical characteristics, etc.) have been implemented. The present review paper aims at reviewing the existing body of literature on the use of artificial micro- and nano-topographical features to control neuronal and neuroglial cells' morphology, outgrowth and neural network topology. The cell responses-from phenomenology to investigation of the underlying mechanisms- on the different topographies, including both deterministic and random ones, are summarized. STATEMENT OF SIGNIFICANCE There is increasing evidence that physical cues, such as topography, can have a significant impact on the neural cell functions. With the aid of micro-and nanofabrication techniques, new types of cell culture platforms are developed and the effect of surface topography on the cells has been studied. The present review article aims at reviewing the existing body of literature reporting on the use of various topographies to study and control the morphology and functions of cells from nervous tissue, i.e. the neuronal and the neuroglial cells. The cell responses-from phenomenology to investigation of the underlying mechanisms- on the different topographies, including both deterministic and random ones, are summarized.
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Affiliation(s)
- C Simitzi
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion 71003, Greece
| | - A Ranella
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion 71003, Greece
| | - E Stratakis
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion 71003, Greece.
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Petridis C, Savva K, Kymakis E, Stratakis E. Laser generated nanoparticles based photovoltaics. J Colloid Interface Sci 2017; 489:28-37. [DOI: 10.1016/j.jcis.2016.09.065] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/25/2016] [Accepted: 09/26/2016] [Indexed: 11/30/2022]
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Kakavelakis G, Alexaki K, Stratakis E, Kymakis E. Efficiency and stability enhancement of inverted perovskite solar cells via the addition of metal nanoparticles in the hole transport layer. RSC Adv 2017. [DOI: 10.1039/c7ra00274b] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Inverted perovskite solar cells with enhanced efficiency and stability are fabricated based on a nanoparticles doped hole transport layer.
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Affiliation(s)
- G. Kakavelakis
- Center of Materials Technology and Photonics
- Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- Heraklion 71004
- Greece
| | - K. Alexaki
- Institute of Electronic Structure and Laser (IESL)
- Foundation for Research and Technology-Hellas (FORTH)
- Heraklion
- Greece
- Physics Department
| | - E. Stratakis
- Department of Materials Science and Technology
- University of Crete
- Heraklion
- Greece
- Institute of Electronic Structure and Laser (IESL)
| | - E. Kymakis
- Center of Materials Technology and Photonics
- Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- Heraklion 71004
- Greece
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Paradisanos I, Pliatsikas N, Patsalas P, Fotakis C, Kymakis E, Kioseoglou G, Stratakis E. Spatial non-uniformity in exfoliated WS2 single layers. Nanoscale 2016; 8:16197-16203. [PMID: 27381081 DOI: 10.1039/c6nr03597c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Monolayers of transition metal dichalcogenides (TMDs) are atomically thin two-dimensional crystals with attractive optoelectronic properties, which are promising for emerging applications in nanophotonics. Here, we report on the extraordinary spatial non-uniformity of the photoluminescence (PL) and strain properties of exfoliated WS2 monolayers. Specifically, it is shown that the edges of such monolayers exhibit remarkably enhanced PL intensity compared to their respective central area. A comprehensive analysis of the recombination channels involved in the PL process demonstrates a spatial non-uniformity across the monolayer's surface and reflects on the non-uniformity of the intrinsic electron density across the monolayer. Auger electron imaging and spectroscopy studies complemented with PL measurements in different environments indicate that oxygen chemisorption and physisorption are the two fundamental mechanisms responsible for the observed non-uniformity. At the same time Raman spectroscopy analysis shows remarkable strain variations among the different locations of an individual monolayer, however such variations cannot be strictly correlated with the non-uniform PL emission. Our results shed light on the role of the chemical bonding in the competition between exciton complexes in monolayer WS2, providing a method of engineering new nanophotonic functions using WS2 monolayers. It is therefore envisaged that our findings could find diverse applications towards the development of TMD-based optoelectronic devices.
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Affiliation(s)
- I Paradisanos
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, 71110 Crete, Greece.
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14
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Stylianakis MM, Konios D, Kakavelakis G, Charalambidis G, Stratakis E, Coutsolelos AG, Kymakis E, Anastasiadis SH. Efficient ternary organic photovoltaics incorporating a graphene-based porphyrin molecule as a universal electron cascade material. Nanoscale 2015; 7:17827-17835. [PMID: 26458268 DOI: 10.1039/c5nr05113d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A graphene-based porphyrin molecule (GO-TPP) was synthesized by covalent linkage of graphene oxide (GO) with 5-(4-aminophenyl)-10,15,20-triphenyl porphyrin (TPP-NH2). The yielded graphene-based material is a donor-acceptor (D-A) molecule, exhibiting strong intermolecular interactions between the GO core (A) and the covalently anchored porphyrin molecule (D). To demonstrate the universal role of GO-TPP as an electron cascade material, ternary blend organic photovoltaics based on [6,6]-phenyl-C71-butyric-acid-methyl-ester (PC71BM) as an electron acceptor material and two different polymer donor materials, poly[N-9'-hepta-decanyl-2,7-carbazole-alt-5,5-(40,70-di-2-thienyl-20,10,30-benzothiadiazole)] (PCDTBT) and the highly efficient poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PTB7), were fabricated. The addition of GO-TPP into the active layer implies continuous percolation paths between the D-A interfaces, enhancing charge transport, reducing exciton recombination and thus improving the photovoltaic performance of the device. A simultaneous increase of short circuit current density (Jsc), open-circuit voltage (Voc) and fill factor (FF), compared to the PTB7:PC71BM reference cell, led to an improved power conversion efficiency (PCE) of 8.81% for the PTB7:GO-TPP:PC71BM-based device, owing mainly to the more efficient energy level offset between the active layer components.
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Affiliation(s)
- M M Stylianakis
- Center of Materials Technology and Photonics & Electrical Engineering Department, School of Applied Technology, Technological Educational Institute (TEI) of Crete, Heraklion, 71004, Crete, Greece.
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15
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Simitzi C, Efstathopoulos P, Kourgiantaki A, Ranella A, Charalampopoulos I, Fotakis C, Αthanassakis Ι, Stratakis E, Gravanis A. Data in support on the shape of Schwann cells and sympathetic neurons onto microconically structured silicon surfaces. Data Brief 2015; 4:636-40. [PMID: 26401519 PMCID: PMC4560728 DOI: 10.1016/j.dib.2015.07.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 07/21/2015] [Accepted: 07/22/2015] [Indexed: 11/07/2022] Open
Abstract
This article contains data related to the research article entitled “Laser fabricated discontinuous anisotropic microconical substrates as a new model scaffold to control the directionality of neuronal network outgrowth” in the Biomaterials journal [1]. Scanning electron microscopy (SEM) analysis is performed to investigate whether Schwann cells and sympathetic neurons alter their morphology according to the underlying topography, comprising arrays of silicon microcones with anisotropic geometrical characteristics [1]. It is observed that although soma of sympathetic neurons always preserves its round shape, this is not the case for Schwann cells that become highly polarized in high roughness microconical substrates.
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Affiliation(s)
- C Simitzi
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece ; Department of Biology, University of Crete, Heraklion, Greece
| | - P Efstathopoulos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
| | - A Kourgiantaki
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
| | - A Ranella
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece
| | - I Charalampopoulos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
| | - C Fotakis
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece ; Department of Physics, University of Crete, Heraklion, Greece
| | - Ι Αthanassakis
- Department of Biology, University of Crete, Heraklion, Greece
| | - E Stratakis
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece ; Department of Materials Science and Technology, University of Crete, Heraklion, Greece
| | - A Gravanis
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece ; Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
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16
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Simitzi C, Efstathopoulos P, Kourgiantaki A, Ranella A, Charalampopoulos I, Fotakis C, Athanassakis I, Stratakis E, Gravanis A. Laser fabricated discontinuous anisotropic microconical substrates as a new model scaffold to control the directionality of neuronal network outgrowth. Biomaterials 2015. [PMID: 26210178 DOI: 10.1016/j.biomaterials.2015.07.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
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 microstructures 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 lengthscale. 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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Affiliation(s)
- C Simitzi
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece; Department of Biology, University of Crete, Heraklion, Greece
| | - P Efstathopoulos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
| | - A Kourgiantaki
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
| | - A Ranella
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece
| | - I Charalampopoulos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
| | - C Fotakis
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece; Department of Physics, University of Crete, Heraklion, Greece
| | - I Athanassakis
- Department of Biology, University of Crete, Heraklion, Greece
| | - E Stratakis
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece; Department of Materials Science and Technology, University of Crete, Heraklion, Greece.
| | - A Gravanis
- Foundation for Research and Technology-Hellas (F.O.R.T.H.), Institute of Electronic Structure and Laser (I.E.S.L.), Heraklion, Greece; Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
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17
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Paci B, Kakavelakis G, Generosi A, Rossi Albertini V, Wright JP, Ferrero C, Konios D, Stratakis E, Kymakis E. Stability enhancement of organic photovoltaic devices utilizing partially reduced graphene oxide as the hole transport layer: nanoscale insight into structural/interfacial properties and aging effects. RSC Adv 2015. [DOI: 10.1039/c5ra24010g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
A powerful insight into the structural and interfacial properties of post-fabricated bulk heterojunction (BHJ) organic photovoltaic (OPV) devices, utilizing partially reduced graphene oxide as the hole transport layer, is reported.
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Affiliation(s)
- B. Paci
- Istituto di Struttura della Materia
- CNR
- 00133 Roma
- Italy
| | - G. Kakavelakis
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- School of Engineering
- Heraklion
- Greece
| | - A. Generosi
- Istituto di Struttura della Materia
- CNR
- 00133 Roma
- Italy
| | | | - J. P. Wright
- European Synchrotron Radiation Facility
- 38000 Grenoble
- France
| | - C. Ferrero
- European Synchrotron Radiation Facility
- 38000 Grenoble
- France
| | - D. Konios
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- School of Engineering
- Heraklion
- Greece
| | - E. Stratakis
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- School of Engineering
- Heraklion
- Greece
| | - E. Kymakis
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- School of Engineering
- Heraklion
- Greece
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18
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Krassas M, Kakavelakis G, Stylianakis MM, Vaenas N, Stratakis E, Kymakis E. Efficiency enhancement of organic photovoltaic devices by embedding uncapped Al nanoparticles in the hole transport layer. RSC Adv 2015. [DOI: 10.1039/c5ra14017j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The effects of incorporating uncapped aluminum nanoparticles, fabricated by laser ablation in liquid, in the hole transport layer of organic photovoltaic devices were systematically investigated. Resulting in about 9% enhancement in the power conversion efficiency.
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Affiliation(s)
- M. Krassas
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- Heraklion 71004
- Greece
- Department of Materials Science and Technology
| | - G. Kakavelakis
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- Heraklion 71004
- Greece
- Department of Materials Science and Technology
| | - M. M. Stylianakis
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- Heraklion 71004
- Greece
| | - N. Vaenas
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- Heraklion 71004
- Greece
| | - E. Stratakis
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- Heraklion 71004
- Greece
- Department of Materials Science and Technology
| | - E. Kymakis
- Center of Materials Technology and Photonics & Electrical Engineering Department
- Technological Educational Institute (TEI) of Crete
- Heraklion 71004
- Greece
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Viskadouros G, Zak A, Stylianakis M, Kymakis E, Tenne R, Stratakis E. Enhanced field emission of WS₂ nanotubes. Small 2014; 10:2398-403. [PMID: 24610733 DOI: 10.1002/smll.201303340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/30/2014] [Indexed: 05/09/2023]
Abstract
Results on electron field emission from free standing tungsten disulfide (WS2) nanotubes (NTs) are presented. Experiments show that the NTs protruding on top of microstructures are efficient cold emitters with turn-on fields as low as 1 V/μm and field enhancement of few thousands. Furthermore, the emission current shows remarkable stability over more than eighteen hours of continuous operation. Such performance and long-term stability of the WS2 cathodes is comparable to that reported for optimized carbon nanotube (CNTs) based emitters. Besides this, it is found that the WS2 cathodes prepared are less sensitive than CNTs in chemical reactive ambients. The high field enhancement and superior reliability achieved indicates a potential for vacuum nanoelectronics and flat panel display applications.
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Affiliation(s)
- G Viskadouros
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion, 71110, Crete, Greece; Technical University of Crete, 73100, Hania, Greece; Electrical Engineering Department and Center of Materials Technology & Laser, School of Applied Technology, Technological Educational Institute of Crete, Heraklion, 71004, Crete, Greece
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Simitzi C, Stratakis E, Fotakis C, Athanassakis I, Ranella A. Microconical silicon structures influence NGF-induced PC12 cell morphology. J Tissue Eng Regen Med 2013; 9:424-34. [PMID: 24497489 DOI: 10.1002/term.1853] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 08/21/2013] [Accepted: 11/08/2013] [Indexed: 11/07/2022]
Abstract
Micro-and nanofabrication techniques provide the opportunity to develop new types of cell culture platform, where the effect of various topographical cues on cellular functions such as proliferation and differentiation can be studied. In this study, PC12 cells were cultured on patterned silicon (Si) surfaces comprising arrays of microcones (MCs) exhibiting different geometrical characteristics and surface chemistries. It was illustrated that, in the absence of nerve growth factor (NGF), PC12 cells increased proliferation on all types of patterned surface, as compared to flat Si surfaces. However, in the presence of NGF, PC12 cells showed different responses, depending on the plating surface. Unlike low and intermediate rough MC surfaces, highly rough ones exhibiting large distances between MCs did not support PC12 cell differentiation, independently of the MCs' chemical coatings. These results suggest that the geometrical characteristics of MCs alone can influence specific cellular functions. Tailoring of the physical properties of arrays of Si MCs in order to identify which combinations of MC topologies and spatially defined chemistries are capable of driving specific cellular responses is envisaged.
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Affiliation(s)
- C Simitzi
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas (IESL-FORTH), Heraklion, Greece; Department of Biology, University of Crete, Heraklion, Crete, Greece
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21
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Paci B, Bailo D, Albertini VR, Wright J, Ferrero C, Spyropoulos GD, Stratakis E, Kymakis E. Spatially-resolved in-situ structural study of organic electronic devices with nanoscale resolution: the plasmonic photovoltaic case study. Adv Mater 2013; 25:4760-4765. [PMID: 23893424 DOI: 10.1002/adma.201301682] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Indexed: 06/02/2023]
Abstract
A novel high spatial resolution synchrotron X-ray diffraction stratigraphy technique has been applied in-situ to an integrated plasmonic nanoparticle-based organic photovoltaic device. This original approach allows for the disclosure of structure-property relations linking large scale organic devices to length scales of local nano/hetero structures and interfaces between the different components.
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Affiliation(s)
- B Paci
- Istituto di Struttura della Materia C.N.R., Via Fosso del Cavaliere 100. 00133 Roma, Italy.
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22
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Barberoglou M, Gray D, Magoulakis E, Fotakis C, Loukakos PA, Stratakis E. Controlling ripples' periodicity using temporally delayed femtosecond laser double pulses. Opt Express 2013; 21:18501-18508. [PMID: 23938722 DOI: 10.1364/oe.21.018501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate the capability to control the ripple periodicity on polycrystalline ZnO films by applying temporally delayed femtosecond double pulses. It is shown that there is a characteristic pulse separation time for which one can switch from low- to high- spatial-frequency ripple formation. Results are interpreted based on the relation of the characteristic delay time with the electron-phonon relaxation time of the material. Our results indicate that temporal pulse shaping can be advantageously used as a mean to control the periodic nanoripples' formation and thus the outcome of laser assisted nanofabrication process, which is desirable for the applications of nanopatterned transparent semiconductors.
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Affiliation(s)
- M Barberoglou
- Foundation for Research & Technology – Hellas, Institute of Electronic Structure and Laser P. O. Box 1527, Heraklion GR-71110, Greece
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23
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Stratakis E, Ranella A, Fotakis C. Biomimetic micro∕nanostructured functional surfaces for microfluidic and tissue engineering applications. Biomicrofluidics 2011; 5:13411. [PMID: 21522501 PMCID: PMC3082348 DOI: 10.1063/1.3553235] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 12/26/2010] [Indexed: 05/05/2023]
Abstract
This paper reviews our work on the application of ultrafast pulsed laser micro∕nanoprocessing for the three-dimensional (3D) biomimetic modification of materials surfaces. It is shown that the artificial surfaces obtained by femtosecond-laser processing of Si in reactive gas atmosphere exhibit roughness at both micro- and nanoscales that mimics the hierarchical morphology of natural surfaces. Along with the spatial control of the topology, defining surface chemistry provides materials exhibiting notable wetting characteristics which are potentially useful for open microfluidic applications. Depending on the functional coating deposited on the laser patterned 3D structures, we can achieve artificial surfaces that are (a) of extremely low surface energy, thus water-repellent and self-cleaned, and (b) responsive, i.e., showing the ability to change their surface energy in response to different external stimuli such as light, electric field, and pH. Moreover, the behavior of different kinds of cells cultured on laser engineered substrates of various wettabilities was investigated. Experiments showed that it is possible to preferentially tune cell adhesion and growth through choosing proper combinations of surface topography and chemistry. It is concluded that the laser textured 3D micro∕nano-Si surfaces with controllability of roughness ratio and surface chemistry can advantageously serve as a novel means to elucidate the 3D cell-scaffold interactions for tissue engineering applications.
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Ranella A, Barberoglou M, Bakogianni S, Fotakis C, Stratakis E. Tuning cell adhesion by controlling the roughness and wettability of 3D micro/nano silicon structures. Acta Biomater 2010; 6:2711-20. [PMID: 20080216 DOI: 10.1016/j.actbio.2010.01.016] [Citation(s) in RCA: 246] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 11/14/2009] [Accepted: 01/11/2010] [Indexed: 02/05/2023]
Abstract
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.
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Affiliation(s)
- A Ranella
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, (IESL-FORTH), Heraklion, Greece
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25
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Vernardou D, Vlachou K, Spanakis E, Stratakis E, Katsarakis N, Kymakis E, Koudoumas E. Influence of solution chemistry on the properties of hydrothermally grown TiO2 for advanced applications. Catal Today 2009. [DOI: 10.1016/j.cattod.2009.02.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Experimental results are presented on the formation of self-organized nanostructures (NSs) on a bulk Al target under its ablation in liquids--water and ethanol--with short laser pulses from 180 femtoseconds (fs) through 350 picoseconds (ps). NSs are characterized by atomic force microscopy, field emission scanning electron microscopy, optical absorption spectroscopy and x-ray diffraction. The period of NSs does not depend on the laser wavelength used from 248 through 800 nm and is approximately 200 nm. NSs on Al show the characteristic absorption peak in the near UV which has been attributed to plasmon oscillation of electrons. The wings of this peak, extending to the visible, lead to a distinct yellow coloration of the processed Al surface. Ultrafast laser structuring of bulk aluminum in liquids may be potentially a promising technique for efficient production of nanosized aluminum.
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Affiliation(s)
- E Stratakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), PO Box 1527, Heraklion 711 10, Greece
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27
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Stratakis E, Kymakis E, Spanakis E, Tzanetakis P, Koudoumas E. Polymer-nanotube composite mats with improved field emission performance and stability. Phys Chem Chem Phys 2009; 11:703-9. [DOI: 10.1039/b813198h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zorba V, Persano L, Pisignano D, Athanassiou A, Stratakis E, Cingolani R, Tzanetakis P, Fotakis C. Making silicon hydrophobic: wettability control by two-lengthscale simultaneous patterning with femtosecond laser irradiation. Nanotechnology 2006; 17:026. [PMID: 34911211 DOI: 10.1088/0957-4484/17/13/026] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Indexed: 06/14/2023]
Abstract
We report on the wettability properties of silicon surfaces, simultaneously structured on the micrometre-scale and the nanometre-scale by femtosecond (fs) laser irradiation to render silicon hydrophobic. By varying the laser fluence, it was possible to control the wetting properties of a silicon surface through a systematic and reproducible variation of the surface roughness. In particular, the silicon-water contact angle could be increased from 66° to more than 130°. Such behaviour is described by incomplete liquid penetration within the silicon features, still leaving partially trapped air inside. We also show how controllable design and tailoring of the surface microstructures by wettability gradients can drive the motion of the drop's centre of mass towards a desired direction (even upwards).
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Affiliation(s)
- V Zorba
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete, Greece
- Physics Department, University of Crete, Heraklion 710 03, Greece
| | - L Persano
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete, Greece
- National Nanotechnology Laboratory (NNL) of National Research Council (CNR), Via Arnesano, 73100, Lecce, Italy
| | - D Pisignano
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete, Greece
- National Nanotechnology Laboratory (NNL) of National Research Council (CNR), Via Arnesano, 73100, Lecce, Italy
| | - A Athanassiou
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete, Greece
| | - E Stratakis
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete, Greece
- Materials Science and Technology Department, University of Crete, Heraklion 710 03, Greece
| | - R Cingolani
- National Nanotechnology Laboratory (NNL) of National Research Council (CNR), Via Arnesano, 73100, Lecce, Italy
| | - P Tzanetakis
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete, Greece
- Physics Department, University of Crete, Heraklion 710 03, Greece
| | - C Fotakis
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete, Greece
- Physics Department, University of Crete, Heraklion 710 03, Greece
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Pateraki LE, Stratakis E. Synthesis and organization of vitellogenin and vitellin molecules from the land crab Potamon potamios. Comp Biochem Physiol B Biochem Mol Biol 2000; 125:53-61. [PMID: 10840641 DOI: 10.1016/s0305-0491(99)00160-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have previously reported that vitellogenin (Vg) of some female animals contained four polypeptides with molecular mass of 181, 115, 105 and 85 kDa, whereas Vg of most animals contained three polypeptides with molecular mass of 115, 105 and 85 kDa. In the present investigation, we examined whether the 181 kDa polypeptide is the precursor of 115 and 105 kDa Vg and vitellin (Vn) polypeptides. Labeling studies, using [35S]methionine on normal vitellogenic animals, showed that the radioactivity was distributed first among the 181 and 85 kDa polypeptides. SDS-PAGE analysis of purified hemolymph Vg from eyestalk ablated female animals revealed in most animals two polypeptides with an apparent molecular mass of 181 and 85 kDa. These results from in vivo experiments corroborated the view that the 115 and 105 kDa Vg and Vn polypeptides are derived from heaviest 181 kDa polypeptide. In addition it was demonstrated that hepatopancreas and ovary of Potamon potamios incubated in vitro with [35S]methionine synthesized five polypeptides with apparent molecular mass of 224, 181, 115, 105, and 85 kDa while the hepatopancreas appeared to secrete the 181, 115, 105 and 85 kDa polypeptides. The major 115, 105 and 85 kDa polypeptides were found to be components of egg Vn, while the 224 kDa polypeptide was found to be minor component of Vg and Vn from hepatopancreas and ovary extracts, respectively. We conclude that the Vn polypeptides produced by ovary are similar to those produced by hepatopancreas.
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Affiliation(s)
- L E Pateraki
- Department of Biology, University of Crete, Heraklion, Greece
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Pateraki LE, Stratakis E. Characterization of vitellogenin and vitellin from land crab Potamon potamios: identification of a precursor polypeptide in the molecule. J Exp Zool 1997; 279:597-608. [PMID: 9399431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A female-specific protein, vitellogenin (Vg), and its corresponding egg vitellin (Vn) were identified in the land crab Potamon potamios. Electrophoretic analysis of the hemolymph protein during the annual reproduction cycle revealed that the processing of vitellogenesis did not occur in males or in females of a previtellogenic stage. The analysis of ovarian and egg extracts revealed the presence of Vn, which was identical to Vg. Both Vg and Vn were present in three different aggregational states that represented monomeric, dimeric, and trimeric species of the proteins. In both proteins, the predominant form was the dimeric, which had a molecular mass of 551 kDa for Vg and 510 kDa for Vn. Under denaturing conditions, each of the individual Vg and Vn aggregates released three polypeptides with molecular masses of 115, 105, and 85 kDa. In spite of the difference in terms of native molecular mass, the Vg and Vn were similar in their lipid, carotenoid, and carbohydrate composition. However, Vg of some animals contained a fourth polypeptide with a molecular mass of 181 kDa. This polypeptide and the three other Vg and Vn polypeptides were immunoreactive against anti-Vg prepared from the 85 kDa Vg polypeptide. Furthermore, proteolytic cleavage experiments confirmed that the 115 and 105 kDa Vg polypeptides were derived from the 181 kDa polypeptide. We conclude that the presence of the 181 kDa polypeptide in the Vg molecule resulted in the higher molecular mass of Vg.
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Affiliation(s)
- L E Pateraki
- Department of Biology, University of Crete, Heraklion, Greece
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Stratakis E, Fragkiadakis G, Carpeli-Moustaizi E. Isolation and characterization of a non sex-specific lipoprotein from hemolymph of fresh water crab Potamon potamios. Biol Chem Hoppe Seyler 1992; 373:665-74. [PMID: 1418681 DOI: 10.1515/bchm3.1992.373.2.665] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A non sex-specific high density lipoprotein (HDL) was isolated from the hemolymph of male fresh water crab Potamon potamios. Antiserum against male lipoprotein precipitated a lipoprotein from ovigerous and non ovigerous females. The lipoprotein was isolated by a combination of KBr density gradient ultracentrifugation and gel filtration on Bio-Gel A-1.5m. Two yellow bands with hydrated density of 1.08 and 1.10 g x ml-1 were observed following density gradient ultracentrifugation. Native polyacrylamide electrophoresis showed a low- and a high-mobility band, staining with Sudan black. Both native bands were resolved to a single 128 kDa band in SDS-PAGE. The relative molecular masses of the two bands, as determined by gel filtration and native gradient gel electrophoresis, were 230 and 440 kDa, respectively. Since the lipid content was 50% and the molecular mass of the apoprotein was 128 kDa, we suggest that the lipoprotein is a monomer and a dimer. Chemical cross-linking experiments support this observation. The isoelectric point of the lipoprotein was pH 5.8. The amino-acid composition was also determined. The lipoprotein contained 50% lipids, with phospholipids being the predominant species (80%). Phosphatidylcholine (66%) and phosphatidylethanolamine (16%) were the predominant phospholipids. The fatty acid content of the lipoprotein was also determined. The lipoprotein contained 68% unsaturated fatty acids with oleate being the dominant species (35%).
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Affiliation(s)
- E Stratakis
- Department of Biology, University of Crete, Greece
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Tentes I, Stratakis E. Partial purification and properties of (Na+ + K+)-ATPase from Potamon potamios. Comp Biochem Physiol C Comp Pharmacol Toxicol 1991; 100:619-24. [PMID: 1687561 DOI: 10.1016/0742-8413(91)90050-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. The tissue distribution of the (Na+ + K+)-ATPase in the freshwater/land crab Potamon Potamios was studied. 2. Gills were found to display the highest total activity in the whole animal (47%) but the highest specific activity was detected in the heart (15.15 mumol Pi/mg protein/min). 3. All other organs tested were found to have low enzyme activity. 4. The freshwater/land crab ATPase enzyme was inhibited by ouabain with a Ki of 0.5 mM.Km values for ATP, Mg2+ and K+ were 1.4, 4.0 and 1.2 mM respectively. The enzyme also showed a break in the Arrhenius plot at 23 degrees C. 5. A purification method of microsomal ATPase is described involving ultracentrifugation and electrofocusing.
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Affiliation(s)
- I Tentes
- Institute of Molecular Biology and Biotechnology, Research Center of Crete, Heraklion, Greece
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Stratakis E, Linzen B. Carbonate dehydratase (carbonic anhydrase) in a spider. Association with the hemolymph lipoprotein. Hoppe Seylers Z Physiol Chem 1984; 365:1187-97. [PMID: 6440849 DOI: 10.1515/bchm2.1984.365.2.1187] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Carbonate dehydratase was detected dissolved in the hemolymph of the tarantula, Eurypelma californicum. The enzyme was purified 31-fold by gel filtration, anion-exchange chromatography, a second gel filtration, and finally, preparative polyacrylamide gel electrophoresis. Zinc content increased during purification to up to 2.4 mol Zn/100 000 g of protein (= 1.58 mg Zn/g protein). In the polyacrylamide electrophoresis of tarantula hemolymph under non-denaturing conditions three major protein bands were observed: hemocyanin, a 16 S lipoprotein and the active band which migrated closely behind the 16 S lipoprotein. After treatment with sodium dodecyl sulfate both the carbonate dehydratase-active protein and the lipoprotein revealed bands corresponding to Mr = 95 000 and 110 000, respectively, but the enzymatically active protein revealed an additional third band with Mr = 40 000. The latter band is though to represent the 'true' carbonate dehydratase protein. Upon isoelectric focusing of material containing carbonate dehydratase activity and lipoprotein, bands were obtained at pH 5.45, 5.6 and 5.7. The band at pH 5.6 contained the peak of enzyme activity, and upon dodecyl sulfate-polyacrylamide gel electrophoresis showed the highest proportion of the 40-kDa polypeptide. It is concluded that tarantula carbonate dehydratase, instead of forming a high molecular mass aggregate, is associated with the 16 S lipoprotein, the latter serving as a carrier for the enzyme. The lipoprotein is probably also involved in other transport processes. It is present in great excess and may therefore occur in two forms, charged with carbonate dehydratase or uncharged. Tarantula carbonate dehydratase is inhibited by acetazolamide and by dansylamide, but not by a number of other known inhibitors, most notably not by 4-(aminomethyl)benzenesulfonamide. Treatment with 1M urea does not affect specific enzyme activity, while 2M urea inhibits by 50%. 2-Mercaptoethanol inhibits activity by 50% at 0.1M. Like other carbonate dehydratases, the tarantula enzyme shows esterase activity. The Km for 4-nitrophenyl acetate is 5mM.
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