Femtosecond laser-inscripted direct ultrafast fabrication of a DNA distributor using microfluidics

A femtosecond laser can be used for single or multiple writing processes to create sub 10-μm lines or holes directly without the use of masks. In this study, we characterized the depth and width of micro-channels created by femtosecond laser micro-scribing in polydimethylsiloxane (PDMS) under various energy doses (1%, 5%, 10%, 15% and 20%) and laser beam passes (5, 10 and 15). Based on a microfluidic simulation in a bio-application, a DNA distributor was designed and fabricated based on an energy dose of 5% and a laser beam pass of 5. The simulated depth and width of the micro-channels was 3.58 and 5.27 μm, respectively. The depth and width of the micro-channels were linearly proportional to the energy dose and the number of laser beam passes. In a DNA distribution experiment, a brighter fluorescent intensity for YOYO-1 Iodide with DNA was observed in the middle channels with longer DNA. In addition, the velocity was the lowest as estimated in the computational simulation. The polymer processability of the femtosecond laser and the bio-applicability of the DNA distributor were successfully confirmed. Therefore, a promising technique for the maskless fabrication of sub 10-μm bio-microfluidic channels was demonstrated.