Rapid cell-patterning and microfluidic chip fabrication by crack-free CO2 laser ablation on glass

Abstract

This paper uses a widely available CO2 laser scriber (λ = 10.6 µm) to perform the direct-writing ablation of quartz, borofloat and pyrex substrates for the development of microfluidic chips and cell chips. The surface quality of the ablated microchannels and the presence of debris and distortion are examined by scanning electron microscopy, atomic force microscopy and surface profile measurement techniques. The developed laser ablation system provides a versatile and economic approach for the fabrication of glass microfluidic chips with crack-free structures. In the laser writing process, the desired microfluidic patterns are designed using commercial computer software and are then transferred to the laser scriber to ablate the trenches. This process eliminates the requirement for corrosive chemicals and photomasks, and hence the overall microchip development time is limited to less than 24 h. Additionally, since the laser writing process is not limited by the dimensions of a photomask, the microchannels can be written over a large substrate area. The machining capability and versatility of the laser writing system are demonstrated through its application to the fabrication of a borofloat microfluidic chip and the writing of a series of asymmetric trenches in a microwell array. It is shown that the minimum attainable trench width is 95 µm and that the maximum trench depth is 225 µm. The system provides an economic and powerful means of rapid glass microfluidic chip development. A rapid cell-patterning method based on this method is also demonstrated.