A Study of Diffusion and Partitioning of Organic Compounds Into Polydimethylsiloxane (PDMS)

Polydimethylsiloxane (PDMS) has many advantages over other materials commonly used in the fabrication of microfluidic devices. PDMS is inexpensive, and also has excellent biocompatibility and optical transparency which makes it particularly well-suited for many biological applications. However, one disadvantage of PDMS is the potential for solvents to swell the material, and for hydrophobic organic compounds to partition from the aqueous phase into the PMDS walls of microfluidic devices. Very high surface area to volume ratios common in microfluidic devices exacerbates this problem. The goal of this study was to measure diffusion and partitioning of commonly used organic compounds including antibiotics as a function of PDMS formulation and treatments including monomer extraction and plasma activation of cured surfaces. This research provides the data necessary to more accurately model and predict partitioning and diffusion effects into and out of PDMS. Better prediction of micro-scale chemical conditions within microfluidic devices will enhance the utility of microfluidic approaches in the basic biological sciences.