Investigation and improvement of reversible microfluidic devices based on glass-PDMS-glass sandwich configuration

Reversibly assembled microfluidic devices are dismountable and reusable, which is useful for a number of applications such as micro- and nano-device fabrication, surface functionalization, complex cell patterning, and other biological analysis by means of spatial-temporal pattern. However, reversible microfluidic devices fabri- cated with current standard procedures can only be used for low-pressure applications. Assembling technology based on glass-PDMS-glass sandwich configuration provides an alternative sealing method for reversible microfluidic devices, which can drastically increase the sealing strength of reversibly adhered devices. The improvement mecha- nism of sealing properties of microfluidic devices based on the sandwich technique has not been fully characterized, hindering further improvement and broad use of this technique. Here, we characterize, for the first time, the effect of various parameters on the sealing strength of reversible PDMS/glass hybrid microfluidic devices, including contact area, PDMS thickness, assembling mode, and external force. To further improve the reversible sealing of glass-PDMS-glass microfluidic devices, we propose a new scheme which exploits mechanical clamp- ing elements to reinforce the sealing strength of glass- PDMS-glass sandwich structures. Using our scheme, the glass-PDMS-glass microchips can survive a pressure up to 400 kPa, which is comparable to the irreversibly bonded PDMS microdevices. We believe that this bonding method may find use in lab-on-a-chip devices, particularly in active high-pressure-driven microfluidic devices.