Common Food-Wrap Film as a Cost-Effective and Readily Available Alternative to Thermoplastic Polyurethane (TPU) Membranes for Microfluidics On-Chip Valves and Pumps

Abstract

Recently, there has been an increasing effort in developing new fabrication methods for rapid prototyping of microfluidic chips using laser cutting and 3D printing. However, although these approaches can readily generate rigid parts of the devices, it is not trivial to integrate flexible components (e.g. on-chip valve and/or pump membranes) within the same build. This has led to the recent adoption of thermoplastic polyurethane (TPU) membranes sandwiched between the rigid layers to introduce the necessary flexibility to the chips. Despite its utility, TPU is not without its challenges—it is relatively expensive and surprisingly difficult to source. To overcome these difficulties, our study introduces the use of common food wrapping film as a cost-effective and readily available alternative to TPU, demonstrating its compatibility in fabricating essential microfluidic components such as on-chip valves and peristaltic pumps. Our findings show that this alternative maintains the performance standards required for sophisticated microfluidic applications while significantly alleviating logistical and financial constraints. The results show high cyclability of the membrane, up to 850,000 in continuous testing conditions, at 1 Hz, while also can block the fluid flow at as low as 250 kPa. Regarding the micropumps, it was shown that adequate flow rate of around 4 μL/min can be achieved.