Fabrication Of Microfluidic Structures Research Articles

Controlling wettability in paper by atmospheric-pressure microplasma processes to be used in µPAD fabrication

Paper-based microfluidic systems are of great interest for cheap, disposable point-of-care diagnostic devices, especially for the use in the developing countries. The development of reliable and cost-effective fabrication methods is therefore of great importance. We present two novel methods and experimental setups for the area-selective creation of hydrophilic channels and hydrophobic barriers utilizing atmospheric-pressure microplasmas based on dielectric barrier discharges within the pores of the paper substrate. One approach is based on a local plasma etching process which is able to remove a hydrophobic coating from the paper fibers, while a second, alternative method uses patterned plasma polymerization to deposit a hydrophobic coating on the fiber structure. Both methods utilize microstructured electrodes to shape the plasma discharge volume to allow the fabrication of microfluidic structures in the substrate. We report on the influence of various processing parameters on the fabrication process and compare the minimal structure dimensions obtained so far and maximum wicking distances achieved. Both fabrication methods led to promising results with structure dimensions of around 400 µm, but the plasma etching process turned out to be superior due to lower cost, faster processing, and better structure edge definition.

Fabrication of microfluidic structures in quartz via micro machining technologies

Microfluidic channels have been created for quartz material using micromechanical manufacturing technologies such as micro laser machining, micro ultrasonic machining, and ultra-precision machining. Ultra-precision machining has been used to manufacture cross-junction channels 14 µm wide and 28 µm deep with a three-dimensional triangle cross-section. Micro laser machining has been used to manufacture U-shaped and [InlineMediaObject not available: see fulltext.]-shaped microfluidic channels. Deep holes and microfluidic channels with a high slenderness ratio (width/depth) can be obtained by using micro ultrasonic machining technology. These three machining techniques are compared with respect to surface profiles and machining quality.

Design and application of low temperature co-fired ceramic substrates for sensors in road vehicles

Abstract Nowadays low temperature co-fired ceramics (further on: LTCC) are used in sensor technology as sensors and actuators. Sensors and actuators are playing an important role in intelligent road vehicles. These sensors and actuators are built up by LTCC Microsystems. The processing of starch powder and polymer based on sacrificial layer for fabrication of microfluidic structures of LTCC is described in this paper. In order to determine the optimal lamination parameters the quality of the structure was examined for 30 different temperature-pressure-time adjustments. Samples were examined by scanning acoustic microscope to detect the subsurface delamination and internal inhomogenities. The acoustic microscopic image of each sample from different lamination method was evaluated by image processing algorithm in MATLAB environment.

Plasma Etching of Poly(dimethylsiloxane): Roughness Formation, Mechanism, Control, and Application in the Fabrication of Microfluidic Structures

AbstractEtching of PDMS in SF6 plasmas is investigated as planar technology for the fabrication of microfluidic devices with simultaneous control of surface topography and wettability. Plasma conditions were optimized for high etch rate, which was achieved at high plasma powers and bias voltages, where PDMS microstructures exhibited good anisotropy. Depending on the etcher wall and the mask material, topography can be controlled from very rough to almost smooth. Independent control of the topography was achieved by treating the rough surfaces with wet etchants. Open microchannels of controlled surface roughness and wettability were fabricated. Subsequently, such microchannels were irreversibly sealed with a PDMS cover plate, for fabrication of enclosed microchannels. Plasma etching of PDMS is proven to be a reliable and indispensable method for the fabrication of microfluidic devices with desired wall roughness and wettability. magnified image

Selective Surface Patterning with an Electric Discharge in the Fabrication of Microfluidic Structures

Selective Surface Patterning with an Electric Discharge in the Fabrication of Microfluidic Structures

Selective Surface Patterning with an Electric Discharge in the Fabrication of Microfluidic Structures

Selective Surface Patterning with an Electric Discharge in the Fabrication of Microfluidic Structures