Abstract

Versatility-driven Membrane Valve Designs for Thermoplastic Microfluidic Devices

Alicia Toh Guek Geok, Research Engineer, Singapore Institute Of Manufacturing Technology

Since the discovery of soft lithography[1] and microfluidic large scale integration[2], PDMS[3] membrane valves have become fundamental elements for flow control in microfluidic platforms. With increased commercialization of microfluidic platforms for biological assays, companies have long sourced for versatile and scalable methods to integrate elastomeric membrane materials into low-cost thermoplastic device manufacturing. While several groups have proposed chemistry-based coupling to integrate elastomeric membranes into thermoplastic devices[4-5], the limited range of materials that can be chemically coupled, presents problems for high versatility device production. In this paper, we present the design and control of pressure-actuated membrane valve modules made of soft materials such as PDMS and RTV silicone, and a biocompatible elastomer- PVS[6]. These valve modules were self-aligned in valve seats within thermoplastic devices made of PMMA[7], PC[8] and COC[9]. Because valve modules are mechanically embedded, this design is amenable to any combination of elastomeric and thermoplastic materials. Valve module functions were demonstrated in the flow selection of 200micron wide delivery channels for dynamic concentration gradient generation in bioassays. At <50 cents to fabricate, this design significantly lowers the production cost of membrane valves in thermoplastic devices and is scalable to existing microfluidic platforms that utilize thermoplastic microarray formats.