Femtosecond laser-induced KOH etching for in-volume microfluidic channels in corning EagleXG glass

초록

Conventional planar or two-dimensional (2D) microfluidic channels have traditionally been fabricated using polymer materials. Although these materials are widely applied across various fields, they exhibit significant limitations, including low throughput, restricted fluid flow rates, and limited particle-handling efficiency. In addition, polymer-based channels have issues such as low thermal and pressure tolerance, inadequate chemical resistance, and challenges with leakage and bonding integrity. In contrast, glass presents a promising alternative due to its superior optical properties, long-term stability, high temperature and chemical resistance, and minimal sample adsorption. However, the complexity of the microelectromechanical systems (MEMS) fabrication processes has historically hindered the use of glass in microfluidics. In this study, we introduce a novel method for fabricating in-volume 3D microfluidic channels within glass substrates via selective laser-induced etching. Using a femtosecond laser with potassium hydroxide (KOH) solution, we etched the CORNING EagleXG glass substrate under various laser parameters to optimize etching conditions. Etching process was conducted at 100 degrees C with durations ranging from 6 to 42 h, producing channel lengths from 147.33 mu m (6 h) to 556.66 mu m (42 h) and channel diameters ranging from 11.15 mu m to 49.72 mu m, respectively. This study demonstrates the process parameters necessary for reliable 3D microfluidic channel fabrication in glass. The findings demonstrate an effective fabrication approach that significantly expands the potential applications of glass microfluidic channels, especially using EagleXG glass, marking a promising advancement in the field.

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