Laser patterning and packaging of CCD-CE-Chips made of PMMA

The rapid manufacturing of functional capillary electrophoresis (CE) chips made of polymethylmethacrylate (PMMA) based on laser processing technologies including structuring, surface functionalization and packaging was investigated. CO2 laser-assisted micro-patterning was demonstrated to have a great potential for the fabrication of micro-channel devices and the production capability of CO2 laser processes has been extended to micro-channels less than 30 μm width. A high reproducibility of micro-channel geometry was attained. The average deviation between the fabricated cross-section areas and the desired cross-section areas of micro-channels was better than 3%. The packaging of these micro-structured transparent polymers was successfully established with a laser transmission welding technique using high-power diode laser radiation. CE-chips with channel widths of 150, 100 and 50μm were fabricated and electro-analytically characterized. For this purpose high frequency contactless conductivity detection (CCD) was established. Detection of small ions (Li+, Na+, and K+) with concentrations down to 0.1 × 10−3 mol/l was performed. Analytical results compare well to those obtained by conventional hot embossing and thermal welding. Furthermore, UV-assisted surface modification can be used to influence the micro-analytical performance. The pattern qualities and analytical results show that laser-based technologies have a great potential for application in flexible and cost-efficient production of polymeric microfluidic devices.