Rapid fabrication of poly(dimethylsiloxane)-based microchip capillary electrophoresis devices using CO2 laser ablation

Abstract

The use of CO(2) laser ablation for the patterning of capillary electrophoresis (CE) microchannels in poly(dimethylsiloxane)(PDMS) is described. Low-cost polymer devices were produced using a relatively inexpensive CO(2) laser system that facilitated rapid patterning and ablation of microchannels. Device designs were created using a commercially available software package. The effects of PDMS thickness, laser focusing, power, and speed on the resulting channel dimensions were investigated. Using optimized settings, the smallest channels that could be produced averaged 33 microm in depth (11.1% RSD, N= 6) and 110 microm in width (5.7% RSD, N= 6). The use of a PDMS substrate allowed reversible sealing of microchip components at room temperature without the need for cleanroom facilities. Using a layer of pre-cured polymer, devices were designed, ablated, and assembled within minutes. The final devices were used for microchip CE separation and detection of the fluorescently labeled neurotransmitters aspartate and glutamate.

Fast production of microfluidic devices by CO2 laser engraving of wax‐coated glass slides

“…Aiming to overcome these disadvantages, polymeric materials such as PDMS , polycarbonate , polyester‐toner , and PMMA have been extensively used. In general, polymeric microchips have been produced by soft lithography , hot embossing , direct‐printing process and laser ablation resulting in faster production methodologies at lower costs. Engraving of glass substrates by femtosecond laser can eliminate the use of cleanroom environments as well as the need for masks and molds during the fabrication, but standard instruments are expensive and not commonly found in chemical laboratories .…”

“…Engraving of glass substrates by femtosecond laser can eliminate the use of cleanroom environments as well as the need for masks and molds during the fabrication, but standard instruments are expensive and not commonly found in chemical laboratories . On the contrary, standard‐grade CO 2 laser engraving has proven suitable for prototyping microfluidic devices in a variety of materials, including PDMS , PMMA , and paper . Due to the low thermal conductivity and significant coefficient of thermal expansion of common soda lime glass, fabrication of microfluidic devices by laser engraving often leads to cracking and/or a poor channel quality.…”

“… demonstrated the possibility of engraving low thermal expansion glasses like quartz, borofloat and Pyrex. The channels obtained featured a narrow Gaussian shape, typically obtained by CO 2 ablation of polymers under high power . Using a layer of water on the surface of the glass, small holes (100–200 μm of diameter) can be produced in Pyrex .…”

Microchip capillary electrophoresis for frontal analysis of free bilirubin and study of its interaction with human serum albumin

“…A quick and inexpensive alternative technology is the use of an infrared CO 2 laser to fabricate polymeric microstructures [33]. Several polymeric materials such as polyester (PE) [34], poly(dimethyl methoxysilane) (PDMS) [35], and PMMA [36] have been successfully used to fabricate microfluidic device by laser machining. It provides a fast and economic method to fabricate complicated microfluidic structure with minimum development time.…”

Stretchable optical waveguides

“…Although patterning of PDMS using wet chemical etching [12,13], reactive ion etching [12,14,15] and laser ablation [16] has been reported, mainly replication based microfabrication techniques are used, and are generally referred to as 'soft lithography' [17]. Specifically for fabricating waveguides in PDMS, several approaches have been reported differing in applied patterning technologies and methods to obtain the refractive index contrast required for waveguiding.…”