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Membraneless microfluidic enzymatic biofuel cells (μEBFCs) operated under the co-laminar flow of fuel and oxidant often face cross-mixing issues, especially at low flow rates. In this work, we propose a new approach to design the single-stream μEBFC based on the investigation of relative positions of the electrodes at the top and bottom of the microchannel. To achieve this, a μEBFC was fabricated with multiwalled carbon nanotube (MWCNT) electrodes via a stencil method. The bioanode and biocathode were modified with glucose dehydrogenase and laccase via direct covalent bonding, respectively. The best results were attained by placing the cathode at the top and anode at the bottom of the microchannel in a Y-shaped two streamflow μEBFC. When a single electrolyte stream was used to achieve more practicality and ease of use, the performance was reduced by 40%. However, with the new design of electrodes in single-stream μEBFC, i.e. cathode at the top and anode at the bottom facing each other in the microchannel, the performance was recovered by 20%. This corresponds to maximum current and power density of 216 ± 12 μA cm−2 and 69.2 ± 9.2 μW cm−2, respectively. The stacking ability of the device was realized by connecting the two cells in series and parallel. The maximum power density delivered by the two single-stream μEBFCs’ stack reached 160 μW cm−2 at 0.3 V. Thus, this study validates the viability of using single-stream μEBFCs in large stacks to power microelectronics more simply and practically.

Fully automated system for sample preparation in molecular diagnostics was developed. The small cartridge with multiple chambers and a rotating valve was designed for automated processes such as extraction, separation and purifications during the DNA sample preparation. The automated processes such as injection, mixing, capturing and valve on/off motions were controlled by an affordable, motorized control system. We demonstrated the automated DNA extraction of pathogenic bacteria using this system. The deviations in the purity and real-time polymerase chain reaction (PCR) detection of the automated DNA extraction samples were clearly decreased. The device provided rapid, reliable, and reproducible sample preparation in comparison with manual DNA extraction. This automated platform can be utilized in emergent point-of-care testing of infectious disease and foodborne bacteria.

We present a 512-channel geometric droplet-splitting microfluidic device that involves the injection of a premixed emulsion for microsphere production. The presented microfluidic device was fabricated using conventional photolithography and polydimethylsiloxane casting. The fabricated microfluidic device consisted of 512 channels with 256 T-junctions in the last branch. Five hundred and twelve microdroplets with a narrow size distribution were produced from a single liquid droplet. The diameter and size distribution of prepared micro water droplets were 35.29 µm and 8.8% at 10 mL/h, respectively. Moreover, we attempted to prepare biocompatible microspheres for demonstrating the presented approach. The diameter and size distribution of the prepared poly (lactic-co-glycolic acid) microspheres were 6.56 µm and 8.66% at 10 mL/h, respectively. To improve the monodispersity of the microspheres, we designed an additional post array part in the 512-channel geometric droplet-splitting microfluidic device. The monodispersity of the microdroplets prepared with the microfluidic device combined with the post array part exhibited a significant improvement.

We developed an integrated PCR system that performs automated sample preparation and fast polymerase chain reaction (PCR) for application in point-of care (POC) testing. This system is assembled from inexpensive 3D-printing parts, off-the-shelf electronics and motors. Molecular detection requires a series of procedures including sample preparation, amplification, and fluorescence intensity analysis. The system can perform automated DNA sample preparation (extraction, separation and purification) in ≤5 min. The variance of the automated sample preparation was clearly lower than that achieved using manual DNA extraction. Fast thermal ramp cycles were generated by a customized thermocycler designed to automatically transport samples between heating and cooling blocks. Despite the large sample volume (50 μL), rapid two-step PCR amplification completed 40 cycles in ≤13.8 min. Variations in fluorescence intensity were measured by analyzing fluorescence images. As proof of concept of this system, we demonstrated the rapid DNA detection of pathogenic bacteria. We also compared the sensitivity of this system with that of a commercial device during the automated extraction and fast PCR of Salmonella bacteria.

The present study investigated the effects of silica aerogel inclusion on the stability of heat generation and heat-dependent electrical characteristics of cementitious composites with carbon nanotube (CNT). The heat generation and heat-dependent electrical characteristics of the specimens were explored under the monotonic and cyclic heating conditions and they were discussed in terms of compressive strength and SEM test results. The test results indicated that the addition of the silica aerogel improved the stability of heat generation and changes in the electrical resistivity of up to 63% and 68%, respectively, upon 20 cycles of the heating tests. The enhancement in the electrical properties is attributed to the fact that the incorporated silica aerogel mitigated the re-distribution of CNT particles due to hydration reaction during the heating process, which in turn improved the stability of heat generation and heat-dependent electrical characteristics of the cementitious composites.

A soundwave is transmitted by adjacent molecules in the medium, and depending on the type of sound, it exhibits various characteristics such as frequency, sound pressure, etc. If the acoustic wavelength of the soundwave is sufficiently long compared with the size of an acoustic element, physical analysis within the sound element could be simplified regardless of the shape of the acoustic element: this is called &ldquo, long wavelength approximation&rdquo, A Helmholtz resonator, a representative acoustic element which satisfies the &ldquo, long wavelength theory&rdquo, consists of a neck part and a cavity part. The Helmholtz resonators can absorb certain frequencies of sound through resonance. To exhibit attenuation properties at ultrasound range, the Helmholtz resonator should be made into a microscale since Helmholtz resonators should satisfy the &ldquo, In this study, Helmholtz resonator inspired acoustic elements were fabricated using MEMS technology, and acoustic attenuation experiments in a water bath were conducted using various shapes and materials. As a result, the fabricated samples showed admirable attenuation properties up to ~13 dB mm&minus, 1 at 1 MHz. The results were analyzed to derive the necessary conditions for the fabrication of acoustic elements with acoustic attenuation properties in ultrasound range.

With increasing interest in induced pluripotent stem cells (iPSCs) in the field of stem cell research, highly efficient infection of somatic cells with virus factors is gaining importance. This paper presents a method of employing microfluidic devices for dynamic cell culture and virus infection in a microchannel. The closed space in the microchannel provided a better environment for viruses to diffuse and contact cell surfaces to infect cells. The microfluidic devices were fabricated by photolithography and soft lithography. NIH/3T3 fibroblast cells were cultured in the microfluidic device in static and dynamic conditions and compared with the conventional culture method of using Petri dishes. Virus infection was evaluated using an enhanced green fluorescent protein virus as a model. Dynamic culture in the microchannel showed similar growth of cells to that in Petri dish culture, but the virus infection efficiency was four-times higher. The proposed dynamic culture system could be useful in iPSC research by providing efficient virus infection tools.

We present geometrically passive T-junction breakup as a high-throughput preparation method for polymer microcarriers. In passive T-junction breakup, an alternative method that can satisfy requirements for uniform size distribution and high production, a polymer solution droplet is split into numerous smaller droplets as it passes T-junctions, and is then polymerized into particles as solvents evaporate. Microparticles generated from poly(lactic-co-glycolic acid) (PLGA) were used to demonstrate the applicability of this method. The proposed method of droplet fission, controlled by microfluidic flow, allowed for preparation of biopolymer particles at 8000 Hz and size distribution of CV < 5%. Feasibility of the prepared PLGA microparticles was verified as microcarriers for functional materials: lidocaine, carbon nanotubes (CNTs), and 3T3 cells. The prepared microparticles showed a slower and more linear drug release profile compared to those generated using the conventional evaporation method. Highly porous microparticles were also prepared successfully using gelatin as a porogen in the T-junction breakup device.

Environmentally friendly microstructure molds with montmorillonite (MMT) or multi-walled carbon nanotube (MWCNT) reinforced polyethylene glycol diacrylate (PEGDA) nanocomposites have been prepared for miniaturized device applications. The micropatterning of MMT/PEGDA and MWCNT/PEGDA with 0.5 to 2.0 wt% of MMTs and MWCNTs was achieved through a UV curing process with micro-patterned masks. Hexagonal dot arrays and complex patterns for microstructures of the nanocomposites were produced and characterized with an optical microscope; their thermal properties were studied by thermogravimetric analysis (TGA). The TGA results showed that these nanocomposites were thermally stable up to 350 °C. Polydimethylsiloxane thin replicas with different microstructures were prepared by a casting method using the microstructured nanocomposites as molds. It is considered that these microstructure molds of the nanocomposites can be used as microchip molds to fabricate nanobio-chips and medical diagnostic chip devices.

In the present work, two types of cost-effective bio-electrodes were fabricated by immobilizing Laccase on commercially available pencil graphite leads, and their electro catalytic activity have been examined. The first type of electrode (E 1 ) was fabricated by electro polymerization of polyaniline on pencil graphite leads on which multi walled carbon nanotubes (MWCNT) was immobilized by covalent bonding, while the second type of electrode (E 2 ) was fabricated by direct coating of MWCNT on pencil graphite leads. Two types of bio-cathodes were fabricated by immobilizing Laccase on the two types of electrodes by covalent bonding. The scanning electron microscopy (SEM) revealed three dimensional porous networks providing large surface area for enzyme immobilization. The maximum open circuit potential (OCP) for E 1 and E 2 bio-cathodes were measured 0.58 V and 0.60 V respectively vs Ag/AgCl reference electrode. The maximum current density observed for E 1 and E 2 electrodes were 295.7 μAcm −2 and 228.94 μAcm −2 respectively. Both electrodes exhibited excellent stability, conserving more than 75% of its optimum activity during the period of measurement.

Display Omitted We demonstrate the fabrication method of enzyme-modified, 3D microelectrode arrays for microfluidic biofuel cells.The 3D microelectrode arrays were fabricated using CNT/Nafion nanocomposites and hydrogel microstencils.We could able to make micro-porous structure of the 3D microelectrode arrays using a plasma-etching process.This enzyme-modified, micro-porous, 3D microelectrode can improve performance of microfluidic biofuel cells. Enzyme-modified, three-dimensional (3D) microelectrode arrays for microfluidic biofuel cell applications were fabricated using carbon nanotube (CNT) reinforced Nafion? nanocomposites and hydrogel microstenciling. CNT/Nafion nanocomposites were prepared by dispersing oxidized, multi-walled CNTs in Nafion solution. A hydrogel microstencil was fabricated using photolithography, soft lithography, and capillary-force lithography. After structuring the nanocomposites with the microstencil, a plasma-etching process was applied to the surface of the nanocomposite in order to obtain a micro-porous structure. Enzymes could be successfully immobilized on the micro-porous structures of nanocomposite surfaces using direct covalent binding.

We present a 512-microchannel geometrical passive breakup device for the mass production of microdroplets. The mass production is achieved through the passive breakup of a droplet into two droplets. The microchannel geometry in the microfluidic device was designed and optimized by focusing on stable droplet splitting for microdroplet preparation and minimizing the hydraulic resistance of the microchannel for achieving high throughput, the minimization of hydraulic resistance was achieved by employing analytical approaches. A total of 512 microdroplets could be prepared from a single liquid plug by making the liquid plug pass through nine sequential T-junctions in the microfluidic device, which led to the splitting of droplets. The microfluidic device was fabricated using conventional photolithography and polydimethylsiloxane (PDMS) casting. We estimated the performance of the microfluidic device in terms of the size distribution and production rate of microdroplets. Microdroplets with a diameter of 40.0 &plusmn, 2.2 &micro, m were prepared with a narrow size distribution (coefficient of variation (CV) &lt, 5.5%) for flow rates of disperse (Qd) and continuous phase (Qc) of 2 and 3 mL/h, respectively. Microdroplet production rates were measured using a high-speed camera. Furthermore, monodisperse microdroplets were prepared at 42.7 kHz for Qd and Qc of 7 and 15 mL/h, respectively. Finally, the feasibility of the fabricated microfluidic device was verified by using it to prepare biodegradable chitosan microspheres.

Photolithography is undoubtedly the most widely used patterning method for the fabrication of micro-and nanofeatures, despite the recent development in some unconventional fabrication techniques that are poised to take over certain applications. But photolithography is still the main fabrication method in industry. To step forward in many applied areas, however, large-area, continuous fabrication system needs to be developed. However photolithography has not been extended to large area continuous patterning like other printing technologies. Photolithography is currently based on wafer scale fabrication and metal deposition process is performed under high vacuum condition. Here we report the development of continuous roll type contact photolithography which is termed photo roll lithography (PRL) and vacuum-free metal filling method. Continuous patterning is achieved was by employing a flexible photomask with Al patterns, which was fabricated by conventional photolithography method. Also, metal nanopowder was stuffed in fabricated PR patterns by puffs, instead of conventional deposition methods. As a feasible application, we demonstrated a fabrication of narrow bus wire for using on display devices.

A sensitive determination of a synthetic fluoroquinolone antibacterial agent, moxifloxacin (MOX), by an enhanced chemiluminescence (CL) method using a microfluidic chip is described. The microfluidic chip was fabricated by a soft-lithographic procedure using polydimethyl siloxane (PDMS). The fabricated PDMS microfluidic chip had three-inlet microchannels for introducing the sample, chemiluminescent reagent and oxidant, and a 500 µm wide, 250 µm deep and 82 mm long microchannel. An enhanced CL system, luminol–ferricyanide, was adopted to analyze the MOX concentration in a sample solution. CL light was emitted continuously after mixing luminol and ferricyanide in the presence of MOX on the PDMS microfluidic chip. The amount of MOX in the luminol–ferricyanide system influenced the intensity of the CL light. The linear range of MOX concentration was 0.14–55.0 ng/mL with a correlation coefficient of 0.9992. The limit of detection (LOD) and limit of quantification (LOQ) were 0.06 and 0.2 ng/mL respectively. The presented method afforded good reproducibility, with a relative standard deviation (RSD) of 1.05% for 10 ng/mL of MOX, and has been successfully applied for the determination of MOX in pharmaceutical and biological samples. Copyright © 2013 John Wiley & Sons, Ltd.

This paper presents a microfluidic approach towards the fabrication of highly monodisperse polyurea microcapsules, 35–500 μm in size, containing n -octadecane (phase change material, PCM). The synthesis consisted of the following two steps: (i) emulsification of n –octadecane, isophorone diisocyanate (IPDI) and dibutyltin dilaurate (DBTDL) in an aqueous mixture of tetraethylenepentamine (TEPA), poly (vinyl alcohol) and sodium dodecyl sulfate (SDS)and (ii) in situ polycondensation between TEPA and IPDI along and outside the tube length. The resulting PCM@polyurea microcapsules underwent a rapid and repeated liquid/solid phase transformation at different temperatures. The average sizes and morphology of the microcapsules were controlled by tuning the flow rate of either the continuous or discontinuous phase. The morphology, polycondensation and phase change behavior of the microcapsules were investigated by optical microscopy equipped with a thermostat plate, scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. The effect of the hydrophobic Fe 3 O 4 nanoparticles (NPs) on the crystallization behavior was also examined in cases of microcapsules with or without NPs.

We present a fabrication method of PDMS microtemplates and their applications into a localized culture of primary mammalian cells. Three types of microtemplates of microwell, microstencil and microcontact printing stamp (mCP) were fabricated, and their feasibilities into cell culture were studied. All of microtemplates were fabricated by PDMS casting from SU-8 mold prepared by photolithography. The pattern used in the test was 500 microm dots. In the culture test of microstencil, a stencil was placed on a glass disk coated with Poly-D-Lysine (PDL) layer. In the other test of microcontact printing, PDL layer was patterned by microcontact printing. The mammalian cells of mouse embryonic fibroblasts (MEF) and cortical neuron were successfully cultured into micropatterns by using the microtemplates. The results showed that cells could be cultured into micropatterns with precisely controlled manner at any shapes and specific size for bioscience study and bioengineering applications.

In this presentation, we propose a fabrication method of PDMS stencil to apply into a localized culture of NIH/3T3 cells. PDMS stencil was fabricated by nitrogen gas blowing and soft lithography from preparing SU-8 master mold by photolithography. PDMS stencil pattern was production of the circle size 20 to . In the culture test of PDMS stencil, a stencil was placed on a glass disk. The NIH/3T3 cells were successfully cultured into micropatterns by using the PDMS stencil. The results showed that cells could be cultured into micropatterns with precisely controlled manner at any shapes and specific size for bioscience study and bioengineering applications.

A sensitive chemiluminescence (CL) method on chip coupled with microfluidic system has been reported for the determination of L-phenylalanine (L-PA). A microfluidic chip device with the detection chamber capable of fast sensing light emitted from the luminol and hydrogen peroxide CL reaction catalyzed by copper sulphate was fabricated for the determination of L-PA. The microfluidic chip was fabricated by a soft-lithographic procedure using polydimethyl siloxane (PDMS). The fabricated PDMS microfluidic chip had four inlet microchannels for introducing the sample, chemiluminescent reagent, Cu(II), and oxidant, and a 500 μm wide, 250 μm deep, and 82 mm long microchannel. The detection was based on the enhancement effect of L-PA on the CL signals of luminol–H2O2–Cu2+ system in an alkaline medium. The CL intensity of the system was enhanced linearly with the concentration of L-PA in the range of 1.5 × 10−9–1.2 × 10−7 mol L−1. The limit of detection was found to be 2.4 × 10−10 mol L−1 with the relative standard deviation of 1.8%. The presented method offers a simple, rapid and easy to handle analytical technique in terms of sensitivity, dynamic range and low detection limit for the determination of L-PA in diet soft drinks and pharmaceutical injection samples.

A rapid and sensitive chemiluminescence (CL) system coupled with a microfluidic chip has been presented to determine vitamin B12 (VB12) based on the reaction of luminol and silver nitrate (AgNO(3)) in the presence of gold nanoparticles (AuNPs). A microfluidic chip was fabricated by a soft-lithographic procedure using polydimethyl siloxane (PDMS) having four inlets and one outlet with a 200 μm wide, 250 μm deep, and 100 mm long microchannel. Ag(+) was used as a chemiluminogenic oxidant in this CL reaction which oxidized luminol to produce strong CL signal in the presence of AuNPs. Luminol reacted with AgNO(3) under the catalysis of AuNPs to produce luminol radicals which reacted with dissolved oxygen and emitted CL light. The proposed CL system was applied to determine the amount of VB12 in VB12 tablets and multivitamin. Under the optimum conditions, the CL intensity of the system was increased with the concentration of VB12 in the range of 0.25-100 ng mL(-1) with the correlation coefficient of 0.9982. The limit of detection was found to be 0.04 ng mL(-1) with the relative standard deviation of 1.56 % for five replicate determinations of 25 ng mL(-1) of VB12. The CL reaction mechanism was demonstrated by UV-visible spectra and CL emission spectra.

A light scanning device with two microfluidic hemicylindrical lenses was demonstrated for adjustable laser sheet beam scanning applications. An elastomeric hemicylindrical lens, whose focal length can be adjusted by control of the applied fluidic pressure, was fabricated by application of the pressurized casting process on polydimethylsiloxane (PDMS) obtained from a prepared microsized mold. The hemicylindrical lens consisted of a thin membrane, a liquid chamber and a microchannel. The applied fluidic pressure deformed the lens membrane and changed the lens shape. The change of the lens shape allowed beam shape transformation or beam scanning according to the relative size of the beam to the lens. By orthogonally placing two microfluidic lenses of different sizes, 1 mm × 5 mm and 3 mm × 15 mm, respectively, a spot laser beam from a 200μm-large pinhole was transformed into laser sheet, and then the laser sheet was scanned. The relationship between the lens properties, including lens curvature and laser beam shaping according to different applied pressures on the lens, were systematically investigated. Laser beam scanning properties of the microfluidic light scanning device were also characterized for various applied pressures and offset distances.

We measured experimentally the properties of fluid dynamics, velocity fields, and the pressure, around stenotic obstruction located inside a circular channel structure. Particle image velocimetry system was employed to obtain velocity fields at the central section of the circular channel in the streamwise direction. The stenosis model used was made of acrylic material with different stenotic aspect ratios. The working fluid was water and it was returned by a centrifugal pump system. Pressure measurements were carried out to validate the effect of a narrow passageway. Results showed that the acceleration of gap flow through stenotic obstruction and the pressure drop in the recirculation regime behind the stenosis model can be observed.

A direct patterning for a barrier rib using the roll-imprinting process is getting more interests in display manufacturing fields. Master roll patterning is one of the important issues in the roll-imprinting process. In this study, a novel fabrication process of micro-patterning on a roller surface by applying the photolithography process is studied. Because the roller surface was a cylindrical shape, the designed pattern was made by using a film mask. Special jigs and roll holder were designed and used for the photolithography on the roll substrate. The roll patterning results showed a feasibility of the proposed method for the photolithography on the roll’s surface.

This paper describes a novel technique for fabrication of micro- and nanofluidic device that consists of a carbon nanotube (CNT) and a polydimethylsiloxane (PDMS) microchannel. Single CNT was placed at desired locations using dielectrophoresis (DEP) and PDMS microchannel was constructed on the aligned CNT via photolithography and soft lithography techniques. This technique enables a CNT to be seamlessly embedded in a PDMS microchannel. Moreover, controlling the PDMS curing condition enables the construction of the device with or without a CNT (the device without CNT has a trace nanochannel in PDMS). Preliminary flow tests such as capillary effect and pressure-driven flow were performed with the fabricated devices. In the capillary effect tests, the flow stopped at the nanochannel in both devices. In the pressure-driven flow lower flow resistance was observed in the device with a CNT.

In this study, the mass fabrication of microelectrode tools for microelectrochemical machining (MECM) was studied using microfabrication processes. The cantilever type geometry of microelectrodes was defined by photolithography processes, and metal patterns were made for electrical contacts. Various fabrication processes were studied for the fabrication of microelectrode tools, such as wet etching, lift-off, and electroforming for metal layer patterning. MECM test results showed feasibility of the fabricated electrode tools. The microfabricated electrodes can be used as micromachining tools for various electrical micromachining of steel mold and parts of microdevices.

We report the results of diffuser lithography applied to a negative-type thick photoresist to fabricate 3-dimensional microstructures suspended on supports. When UV light passes through a diffuser film, the direction of the light is randomized because of the irregular surface of the diffuser. By exposing through a diffuser on a Cr-mask, a circular or an elliptical cross-section of exposed region can be formed on a spin-coated photoresist. When applied to a negative-type thick photoresist, diffuser lithography gives a 3-dimensional circular cross-section of the exposed and cross-linked regions, which could be used for making suspended microstructures. The size of the exposed region has been controlled by the dose of the UV light. The current study clearly shows that the depth of exposed region of photoresist is affected by the geometry of the pattern. By controlling the depth of the exposed region using different pattern size, beam structures suspended on the support structures could be fabricated by single exposure process. The characteristics of the diffuser lithography process were investigated on a negative type photopolymer, SU-8, with different doses of UV-light and different geometry.

Three-dimensional (3D) electrode microarrays with multi-walled carbon nanotubes (MWCNTs) reinforced Nafion nanocomposites were prepared for microfluidic biofuel cells. The oxidized MWCNTs (ox-MWCNTs) were prepared using chemical reactions with 60% nitric acid solution with pristine MWCNTs at 120 degrees C for 12 hrs with a nitrogen gas flow environment. Ox-MWCNTs in the range of 1 to 20 wt.% based on the Nafion polymer weight were reinforced to Nafion nanocomposites by solution casting. The micro-porous structure of the ox-MWCNTs reinforced Nafion nanocomposites was prepared by plasma etching for 5 to 20 min. The 10 wt.% ox-MWCNTs reinforced Nafion nanocomposite produced stable micro-porous structures of 3D electrodes by 10 min plasma etching. Micro-scale 3D structures of MWCNTs reinforced Nafion nanocomposites in a diameter range of 47 to 300 μm were prepared by the micro-stencil assisted casting. To characterize the 3D electrode microarrays, the physical geometry and the reinforced MWCNT dispersion in the nanocomposite structure were examined using a scanning electron microscope (SEM) and an optical microscope. Thermal property measurements of the ox-MWCNTs reinforced Nafion nanocomposites with 10 min of plasma etching, and without plasma etching were made. Both showed stable thermal properties over 300 degrees C. The proposed 3D electrode microarray of MWCNT/Nafion nanocomposites with micro-porous structures can be applied to miniaturized fuel cell devices.

SU-8 is a photoplastic polymer with a wide range of possible applications in microtech- nology. Cantilevers designed for atomic force microscopes were fabricated in SU-8. The mechanical properties of these cantilevers were investigated using two microscale testing techniques: contact surface profilometer beam deflection and static load deflection at a point on the beam using a specially designed test machine. The SU-8 Young's modulus value from the microscale test methods is approximately 2-3 GPa.

A rapid and simple method to fabricate tiny shadow-masks and their use in multi-layer surface patterning with in situ micromechanical alignment is presented. Instead of using silicon micromachining with through-wafer etching to define the thin membrane with etched apertures, we are using photoplastic SU-8-based resist as structural material of both membrane and support rim. Two layers, 5 and 150 μm thick, are structured by lithography and finally released from the surface. The free-standing SU-8 membranes have apertures ranging from 6 to 300 μm. They are placed and mechanically fixed to the surface, which needs to be patterned. Deposition by evaporation of Cr, Au, Al or other material through the membrane apertures results in an accurate 1:1 replication of the aperture pattern. In view of multi-layer patterning, we used in situ micromechanical alignment pins or jigs and achieved an overlay precision of

Haptic is a tactile feedback technology which has the advantage of the sense of touch by applying forces, vibrations or motions to the user. To use the haptic device for remote control, it is need to sense the object. These sensors are called as haptic sensor, and it senses the magnitude, direction, and distribution of a force. The sensed force data are used to reproduce the boundary limit of remote user's movement or the reactions from objects. We develop an elastic material based tactile sensor for sensing the reaction force and the shape of contact surface. Sensor surface is made of Poly-dimethylsiloxane(PDMS) and it has small patterns with chrome. The deformation of these patterns is calculated by computer vision. By this process we could know the amount force that gave from some object. We performed the experiment with force sensor to find the relationship between the force and deformation of surface.

The determination of L-ascorbic acid (AA) by a high throughput chemiluminescence (CL) method using a metal ion attached multiwalled carbon nanotubes (MWCNTs) immobilized microfluidic chip has been developed. The method is based on enhancing CL intensity of the luminol-hydrogen peroxide system with the immobilized metal-MWCNTs in the microfluidic chip and on the quenching of CL intensity with addition of AA. The effects of pH, concentrations of luminol, hydrogen peroxide and metal ions on the CL intensity were investigated and optimized. The calibration curve for AA was linear over the range of 1.6×10 -8 M to 6.4×10 -7 M, the correction coefficient was 0.98913 and the detection limit was 1.11×10 -9 M.

A low-cost method for nanostencil fabrication is demonstrated. The micro-stencils were fabricated by means of standard MEMS processes of conventional photolithography and bulk etching of Si substrate. The size of the micro-apertures was reduced down to sub-micron-meter scale by the additional deposition of SiO2 on SiN stencil membrane. In this study, 500- mum-thick SiO2 were deposited by PECVD from upside and downside of the stencil in order to study the size reduction of the apertures. Because the micro-aperture has a taper in the membrane of the micro-stencil due to SiN membrane etching, the deposition rate showed different with deposition direction.

In this study, an air-knife system was developed for the automated fabrication of polymer microstencils with microscale perforated patterns. Blowing compressed N2 gas through the air knife provided a uniform laminar gas flow of high intensity suitable for perforating holes in the stencil. The polydimethylsiloxane (PDMS) stencil was replicated from a master mold prepared by photolithography. When the prepolymer of PDMS was spin-coated onto the master mold, a thin layer of the prepolymer remained on top of the master's structure and consequently prevented the formation of the perforated patterns. This residual layer was easily removed by the presented air knife. The air-knife system controlled the flow rate of N2 gas and the conveying speed of the master mold; therefore, the system possessed high reproducibility compared to manual gas blowing. Its use reduced the fabrication time for perforated biocompatible polymer microstencils, allowing for their mass production via an automated system. The validity of this suggested method was proven through experiments and was evaluated by application in various fields.

A rapid and simple fabrication method to construct tiny shadow-masks and their use in multi-layer surface patterning with in-situ micromechanical alignment is presented. Free-standing shadow-mask membranes are made of a 5-µm-thick SU-8 based resist layer by photolithography. They are supported by a 1-mm-large and 150-µm-thick SU-8 rim. The membrane has apertures with feature sizes ranging from 6–300 µm. Multiple layer deposition by electron beam evaporation of Cr, Au and Al through the membrane apertures results in aligned multilayer patterns. By using in-situ micromechanical alignment pins or jigs we achieved an overlay precision of < 2 µm in both, x and y direction. The resistless shadow mask deposition technique eliminates photolithography processes and allows surface patterns to be made in a rapid and vacuum-clean way on arbitrary millimeter-size surfaces, and at low-cost.

An elastomeric microfluidic lens of variable focal length was fabricated by single casting from a microfabricated mold. The lens is a poly(dimethylsiloxane) (PDMS) microfluidic chamber covered with a thin membrane. By introducing fluid inside, the pressure varied in the microfluidic chamber, which produced a shift in the microlens focal plane resulting in a change in the back focal length of the lens. Hot pressing was used to fabricate the microfluidic chamber and membrane in a single body. The fabrication processes are simple, avoid handling difficulties of the thin membrane, and provide uniform thickness of the membrane, which essentially affect lens performance. The optical properties of the lens such as lens shape, back focal length, and numerical aperture were calculated and measured at various lens geometries and applied pressures. The back focal length of the lens changed approximately from 30 to 5 mm. The relationships of the optical properties, namely, back focal length and numerical aperture, with applied pressure were studied and verified using optical image tests. The variable focal length of the microfluidic lens is critical to increase the efficiency of light detection in optical or biophotonic applications.

We are reporting for the first time the pH responsiveness of liquid crystal (LC) microdroplets decorated with an amphiphilic block copolymer of PAA-b-LCP. We successfully demonstrated the adsorption of block copolymer on LC droplets by fluorescence microscopy and pH response to the radial-to-bipolar orientational change of the LC droplets by changing pH from 12 to 2 through the polarized optical microscope (POM). We believe that our results may pave the way for the generation of monodisperse droplets decorated by various amphiphilic block copolymers which respond to several kinds of the external stimuli. These developments may be important for potential applications of the LC droplets in sensing and encapsulation fields.

A new concept based on microstructuring techniques is presented to achieve size-dependent electrophoretic migration of DNA in free solution. Topographically structured microfluidic channels with periodical cavities in the range of the radius of gyration of the tested DNA molecules (< 3 µm) are produced by moulding of polydimethylsiloxane on a master wafer fabricated by contact lithography of SU-8 photoresist. The electrophoretic migration of single DNA molecules stained with the intercalator YOYO was investigated by real-time fluorescence video microscopy. It could be demonstrated for large DNA molecules that [lambda]-DNA (48 kbp) always migrated significantly faster than T2-DNA (164 kbp) in the two tested microchannel layouts. Integration into a microdevice for DNA separation in free solution is now in progress.