An automated sampling workflow for parallel long-term membrane diffusion cell testing

Abstract

Permeation tests are an important but time-intensive component of membrane characterization that often requires recurring data collection over extended periods of time. Here we present a new workflow for automating long-term membrane permeation testing. Through the use of open-source software and 3D-printed labware, we have automated and parallelized the periodic collection of liquid samples from membrane diffusion cell tests conducted in H-cells. Capable of parallelizing up to 8 H-cell diffusion tests at a time, this workflow allows for round-the-clock data collection without the need for manual sampling. In tandem with UV-vis characterization, we demonstrate the usage of this workflow by measuring the diffusion coefficients of four aqueous dyes of varying composition through poly(ethylene glycol) diacrylate (PEGDA)-based hydrogel membranes. The materials and scripts presented here have been published for easy implementation to other research projects that require repeated sample collection over extended periods of time. Developed with standard labware and tools in mind, this workflow is not only compatible with the Opentrons OT2 robot, but could also be adapted to other commercially available liquid handling platforms.