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

## TL;DR

This paper shows that common food-wrap film can replace expensive TPU membranes in microfluidic devices, offering a low-cost and accessible solution for creating valves and pumps.

## Contribution

The study introduces food-wrap film as a novel, low-cost alternative to TPU membranes for microfluidic on-chip valves and pumps.

## Key findings

- FWF valves maintained reliable sealing at 40 psi and stable flow rates during peristaltic operation.
- FWF sustained over one million actuation cycles without performance degradation and withstood burst pressures up to 60 psi.
- FWF's thermal resistance enabled effective bonding with PMMA layers, simplifying device assembly.

## Abstract

Microfluidic devices rely on precise fluid control to enable complex operations in diagnostics, chemical synthesis, and biological research. Central to this control are microvalves, which regulate on-chip flow but require flexible membranes for active operation. While the laser cutting of thermoplastics offers a fast, automated method for fabricating rigid microfluidic components, integrating flexible elements like valves and pumps remains a key challenge. Thermoplastic polyurethane (TPU) membranes have been adopted to address this need but are costly and difficult to procure reliably. In this study, we present commercial food-wrap film (FWF) as a low-cost, widely available alternative membrane material. We demonstrate FWF’s compatibility with laser-cut thermoplastic microfluidic devices by successfully fabricating Quake-style valves and peristaltic pumps. FWF valves maintained reliable sealing at 40 psi, maintained stable flow rates of ~1.33 μL/min during peristaltic operation, and sustained over one million continuous actuation cycles without performance degradation. Burst pressure testing confirmed robustness up to 60 psi. Additionally, FWF’s thermal resistance up to 140 °C enabled effective thermal bonding with PMMA layers, simplifying device assembly. These results establish FWF as a viable substitute for TPU membranes, offering an accessible and scalable solution for microfluidic device fabrication, particularly in resource-limited settings where TPU availability is constrained.