Fabrication of PEG-Plasticized Epoxy Resin-Based Microfluidic Chips by Casting over PMMA Mold for PCR Applications: Influence CO2 Laser-Ablation Parameters of Mold

Abstract

Despite dimethyl siloxane (PDMS) being one of the most used microfluidics chips, its micromachining techniques are infeasible for the mass production of commercial devices. This study proposed Epoxy Resin (ER) as a promising, cost-effective alternative to PDMS in lab-on-chip applications, including Polymerase Chain Reactions (PCR). Moreover, a novel, rapid and non-photolithographic approach has been developed for micromachining epoxy microfluidic chips. A new method for fabricating epoxy resin and polyethylene glycol (PEG) hybrid (ER-PEG) microchannels was developed by casting replication over PMMA molds. A PMMA piece was engraved with a CO2 laser in the raster mode to produce the mold for the ER-PEG casting first. A positive mold was fabricated from a polymethyl methacrylic acid (PMMA) sheet (6mm) by CO2 laser ablation. The microfluidic chips with the negative pattern were replicated by casting thermoset epoxy resin onto the micro-machined PMMA mold. The entire process, from device design conception to working device, can be completed in minutes. Herein, to enhance the surface roughness (Ra) of the ablated mold surface, different Distances to Focus (DF) were tried. The low Ra in the mold results in a low Ra in the replica. Also, the performance of ER-PEG in PCR was evaluated to verify the compatibility of the chip material to the PCR test.