Thin Microfluidic Chips with Active Valves

Abstract We report the fabrication of very thin microfluidic active and passive devices on rigid and flexible substrates for sample-space-restricted applications. Thin glass coverslips are commonly used substrates, but these being fragile often crack during experiments, leading to device failure. Here, we used PET as a flexible substrate to fabricate robust thin devices. We proposed a simpler process for PET-PDMS bonding without any silane, adhesive, and/or plasma treatment. We presented the compatibility of the thin devices with a digital in-line holographic microscope (DIHM) as a use case. The substitution of the conventional microscope with DIHM in microfluidic large-scale integrated systems renders simplicity, cost-effectiveness, portability, and miniaturization of the overall system. It also enables a customized and parallel multisite optical observation for a complex microfluidic circuit chip. These chips comprise various microfluidic components made of active microvalves, particularly Quake valves. We also successfully demonstrated the function of microvalves fabricated with our method to regulate the fluidic flow. Thus, are suited to making sophisticated microfluidic circuit chips to fit a variety of applications like organ-on-chip, cell culture, wearable biosensors, pressure sensors, etc.