Simple Surface Modification of Poly(dimethylsiloxane) via Surface Segregating Smart Polymers for Biomicrofluidics
Originally published in Scientific Reports volume 9, Article number: 7377 (2019).
https://www.nature.com/articles/s41598-019-43625-5#rightslink
Abstract
Poly(dimethylsiloxane) (PDMS) is likely the most popular material for microfuidic devices in lab-on-achip and other biomedical applications. However, the hydrophobicity of PDMS leads to non-specifc adsorption of proteins and other molecules such as therapeutic drugs, limiting its broader use. Here, we introduce a simple method for preparing PDMS materials to improve hydrophilicity and decrease nonspecifc protein adsorption while retaining cellular biocompatibility, transparency, and good mechanical properties without the need for any post-cure surface treatment. This approach utilizes smart copolymers comprised of poly(ethylene glycol) (PEG) and PDMS segments (PDMS-PEG) that, when blended with PDMS during device manufacture, spontaneously segregate to surfaces in contact with aqueous solutions and reduce the hydrophobicity without any added manufacturing steps. PDMS-PEGmodifed PDMS samples showed contact angles as low as 23.6°±1° and retained this hydrophilicity for at least twenty months. Their improved wettability was confrmed using capillary fow experiments. Modifed devices exhibited considerably reduced non-specifc adsorption of albumin, lysozyme, and immunoglobulin G. The modifed PDMS was biocompatible, displaying no adverse efects when used in a simple liver-on-a-chip model using primary rat hepatocytes. This PDMS modifcation method can be further applied in analytical separations, biosensing, cell studies, and drug-related studies.