Modular membrane valves for universal integration within thermoplastic devices

Abstract

While much research has been conducted on elastomeric valves within PDMS microfluidic devices, we rarely see scalable manufacturing processes for integrating such valves into rigid thermoplastic devices. Most thermoplastic materials do not share intrinsic bonding compatibility to flexible elastomer membranes, making it difficult to ensure leak-proof operation of such valves within thermoplastic devices. In order to overcome bonding compatibility issues, we propose decoupling the valve architecture from the fluidic routing device layers. This can be achieved by prefabricating modular valves via molding processes and subsequently inserting them into thermoplastic layers containing valve seats. Thermoplastic layers containing modular valves are then thermally bonded to thermoplastic layers containing the fluidic routing channels, resulting in leak-proof valve integration. At valve actuation pressures of approximately 60 kPa, the modular membrane valves seal fluidic channels operating at a flow rate of 100 µl min−1. Modular valves that were incorporated into a concentration gradient generator demonstrated dynamically configurable fluid routing at a response frequency of 5 Hz. The integration of modular membrane valves is an effective solution to streamline and cost-down the manufacturing of hybrid elastomer–thermoplastic devices. As this solution does not rely on bonding compatibility between the elastomeric membranes and the thermoplastic device, it can be applied universally to solve integration issues for low-cost thermoplastic device fabrication.