S. Szilasi - Academia.edu (original) (raw)

Papers by S. Szilasi

Research paper thumbnail of Fabrication of a microfluidic cell capture device by the combination of proton beam writing and soft lithography: 1. design and feasibility

ELECTROPHORESIS, 2015

Design, fabrication, integration, and feasibility test results of a novel microfluidic cell captu... more Design, fabrication, integration, and feasibility test results of a novel microfluidic cell capture device is presented, exploiting the advantages of proton beam writing to make lithographic irradiations under multiple target tilting angles and UV lithography to easily reproduce large area structures. A cell capture device is demonstrated with a unique doubly tilted micropillar array design for cell manipulation in microfluidic applications. Tilting the pillars increased their functional surface, therefore, enhanced fluidic interaction when special bioaffinity coating was used, and improved fluid dynamic behavior regarding cell culture injection. The proposed microstructures were capable to support adequate distribution of body fluids, such as blood, spinal fluid, etc., between the inlet and outlet of the microfluidic sample reservoirs, offering advanced cell capture capability on the functionalized surfaces. The hydrodynamic characteristics of the microfluidic systems were tested with yeast cells (similar size as red blood cells) for efficient capture.

Research paper thumbnail of Fabrication of a microreactor by proton beam writing technique

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2009

Microreactors are innovative and promising tools in technology nowadays because of their advantag... more Microreactors are innovative and promising tools in technology nowadays because of their advantages compared to the conventional-scale reactors. These advantages include vast improvements in surface to volume ratio, energy efficiency, reaction speed and yield and increased control of reaction conditions, to name a few examples.

Research paper thumbnail of Si micro-turbine by proton beam writing and porous silicon micromachining

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 2009

A 3D Si micro-turbine characterized by high aspect ratio vertical walls was formed by the combina... more A 3D Si micro-turbine characterized by high aspect ratio vertical walls was formed by the combination of proton beam writing (PBW) and subsequent selective porous Si (PS) etching. Crystal damages generated by the implanted protons result in increased resistivity, thereby limit or even prevent the current to flow through the implanted area during electrochemical etching. Characteristic feature of the proposed process is that the shape of the micro electro-mechanical (MEMS) components is defined by two implantation energies. A higher energy is applied for defining the housing of the device while the lower energy is used to write the moving components. The implantation energies were selected such as to result appropriate difference between the two projected ranges, thereby providing structures with different height after development. The thickness of the walls of the moving component and the isotropic etching profile of the electrochemical PS formation was also taken into consideration. The electrochemical etching is driven until the sacrificial PS layer completely underetches the moving components, but the etch-front does not reach the bottom of the housing. Therefore, the dissolution of PS results in a ready-to-operate device with a released moving component embedded in the cavity of the housing. This work is the first demonstration of a silicon device containing a moving part made by proton beam writing.

Research paper thumbnail of Nanochannel alignment analysis by scanning transmission ion microscopy

Nanotechnology, 2010

In this paper a study on the ion transmission ratio of a nanoporous alumina sample is presented. ... more In this paper a study on the ion transmission ratio of a nanoporous alumina sample is presented. The sample was investigated by scanning transmission ion microscopy (STIM) with different beam sizes. The hexagonally close-packed Al(2)O(3) nanocapillary array, realized as a suspended membrane of 15 microm thickness, had pore diameters of approximately 215 nm and spacing of approximately 450 nm. When the proton beam size was limited to a single domain, a peak transmission ratio of 19% was observed as is expected from the geometry (approximately 19-20%). This result points out an almost perfectly parallel alignment of the capillaries within one domain. However, for larger beam scanning areas (sampling multiple domains) the transmission ratio was reduced to 5%. The STIM analysis over an area larger than the typical domain size revealed an overall capillary angular spread of approximately 2 degrees.

Research paper thumbnail of 4 He + Ion Beam Irradiation Induced Modification of Poly(dimethylsiloxane). Characterization by Infrared Spectroscopy and Ion Beam Analytical Techniques

Research paper thumbnail of Test of image acceleration by distant collision of proton microbeam

Journal of Physics: Conference Series, 2012

ABSTRACT Charged particles in front of surfaces always accelerate towards the surface due to the ... more ABSTRACT Charged particles in front of surfaces always accelerate towards the surface due to the attractive image force between the charge and the surface. It is shown that using capillary transmission by charged particle projectiles the image acceleration can be clearly studied without close collision with the inner surface. We present experimental studies of the deflection of the proton microbeam with energy of 1 MeV as a function of the entering beam position parallel to the capillary axis when they pass through the steel macro-capillary.

Research paper thumbnail of Fabrication of a microfluidic cell capture device by the combination of proton beam writing and soft lithography: 1. design and feasibility

ELECTROPHORESIS, 2015

Design, fabrication, integration, and feasibility test results of a novel microfluidic cell captu... more Design, fabrication, integration, and feasibility test results of a novel microfluidic cell capture device is presented, exploiting the advantages of proton beam writing to make lithographic irradiations under multiple target tilting angles and UV lithography to easily reproduce large area structures. A cell capture device is demonstrated with a unique doubly tilted micropillar array design for cell manipulation in microfluidic applications. Tilting the pillars increased their functional surface, therefore, enhanced fluidic interaction when special bioaffinity coating was used, and improved fluid dynamic behavior regarding cell culture injection. The proposed microstructures were capable to support adequate distribution of body fluids, such as blood, spinal fluid, etc., between the inlet and outlet of the microfluidic sample reservoirs, offering advanced cell capture capability on the functionalized surfaces. The hydrodynamic characteristics of the microfluidic systems were tested with yeast cells (similar size as red blood cells) for efficient capture.

Research paper thumbnail of Fabrication of a microreactor by proton beam writing technique

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2009

Microreactors are innovative and promising tools in technology nowadays because of their advantag... more Microreactors are innovative and promising tools in technology nowadays because of their advantages compared to the conventional-scale reactors. These advantages include vast improvements in surface to volume ratio, energy efficiency, reaction speed and yield and increased control of reaction conditions, to name a few examples.

Research paper thumbnail of Si micro-turbine by proton beam writing and porous silicon micromachining

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 2009

A 3D Si micro-turbine characterized by high aspect ratio vertical walls was formed by the combina... more A 3D Si micro-turbine characterized by high aspect ratio vertical walls was formed by the combination of proton beam writing (PBW) and subsequent selective porous Si (PS) etching. Crystal damages generated by the implanted protons result in increased resistivity, thereby limit or even prevent the current to flow through the implanted area during electrochemical etching. Characteristic feature of the proposed process is that the shape of the micro electro-mechanical (MEMS) components is defined by two implantation energies. A higher energy is applied for defining the housing of the device while the lower energy is used to write the moving components. The implantation energies were selected such as to result appropriate difference between the two projected ranges, thereby providing structures with different height after development. The thickness of the walls of the moving component and the isotropic etching profile of the electrochemical PS formation was also taken into consideration. The electrochemical etching is driven until the sacrificial PS layer completely underetches the moving components, but the etch-front does not reach the bottom of the housing. Therefore, the dissolution of PS results in a ready-to-operate device with a released moving component embedded in the cavity of the housing. This work is the first demonstration of a silicon device containing a moving part made by proton beam writing.

Research paper thumbnail of Nanochannel alignment analysis by scanning transmission ion microscopy

Nanotechnology, 2010

In this paper a study on the ion transmission ratio of a nanoporous alumina sample is presented. ... more In this paper a study on the ion transmission ratio of a nanoporous alumina sample is presented. The sample was investigated by scanning transmission ion microscopy (STIM) with different beam sizes. The hexagonally close-packed Al(2)O(3) nanocapillary array, realized as a suspended membrane of 15 microm thickness, had pore diameters of approximately 215 nm and spacing of approximately 450 nm. When the proton beam size was limited to a single domain, a peak transmission ratio of 19% was observed as is expected from the geometry (approximately 19-20%). This result points out an almost perfectly parallel alignment of the capillaries within one domain. However, for larger beam scanning areas (sampling multiple domains) the transmission ratio was reduced to 5%. The STIM analysis over an area larger than the typical domain size revealed an overall capillary angular spread of approximately 2 degrees.

Research paper thumbnail of 4 He + Ion Beam Irradiation Induced Modification of Poly(dimethylsiloxane). Characterization by Infrared Spectroscopy and Ion Beam Analytical Techniques

Research paper thumbnail of Test of image acceleration by distant collision of proton microbeam

Journal of Physics: Conference Series, 2012

ABSTRACT Charged particles in front of surfaces always accelerate towards the surface due to the ... more ABSTRACT Charged particles in front of surfaces always accelerate towards the surface due to the attractive image force between the charge and the surface. It is shown that using capillary transmission by charged particle projectiles the image acceleration can be clearly studied without close collision with the inner surface. We present experimental studies of the deflection of the proton microbeam with energy of 1 MeV as a function of the entering beam position parallel to the capillary axis when they pass through the steel macro-capillary.