Bench scale glass-to-glass bonding for microfluidic prototyping

Microfluidics, an increasingly ubiquitous technology platform, has been extensively utilized in assorted research areas. Commonly, microfluidic devices are fabricated using cheap and convenient elastomers such as poly(dimethylsiloxane) (PDMS). However, despite the popularity of these materials, their disadvantages such like deformation under moderate pressure, chemical incompatibility, and surface heterogeneity have been widely recognized as impediments to expanding the utility of microfluidics. Glass-based microfluidic devices, on the other hand, exhibit desirable properties including rigidity, chemically inertness, and surface chemistry homogeneity. That the universal adoption of glass-based microfluidics has not yet been achieved is largely attributable to the difficulties in device fabrication and bonding, which usually require large capital investment. Therefore, in this work, we have developed a bench-scale glass-to-glass bonding protocol that allows the automated bonding of glass microfluidic devices within 6 h via a commercially available furnace. The quality of the bonds was inspected comprehensively in terms of bonding strength, channel deformation and reliability. Additionally, femtosecond pulsed laser micromachining was employed to rapidly engrave channels on a glass substrate with arbitrary-triangular in this case-cross-section. Bonded glass microfluidic devices with machined channels have been used to verify calculated capillary entry pressures. This combination of fast laser micromachining that produces arbitrary cross-sectioned microstructures and convenient bench-scale glass bonding protocol will facilitate a broad range of micro-scale applications.