Surface Modification of Polydimethylsiloxane via Combined Aminolysis and Alcoholysis Generating Cell Adhesive and Antifouling Properties

Abstract

Polydimethylsiloxane (PDMS) is an elastomeric polymer frequently used as implant material, for flexible tubing and in microfluidic devices. The pronounced hydrophobic surface of this unique material impedes many applications where a good wetting behavior is required. Consequentially, various ways of surface modifications have been used to introduce new properties. Plasma treatment is the most popular technique in this respect, but is not generally applicable, especially if hardly accessible surfaces are to be modified. A novel wet-chemistry-based modification scheme yielding an amino-functionalized PDMS surface using a combined alcoholysis/aminolysis reaction is presented. Biological applications are exemplified by the conjugation of the RGD peptide, or polyethylene glycol (PEG) and heparin, yielding surfaces with cell-adhesive or nonthrombogenic properties, respectively. The effect of subsequent conjugation with an adhesive peptide is tested in cell culture. Additionally, two antifouling surfaces generated by coupling heparin and polyethylene glycol respectively are shown to improve the materials resistance to platelet adhesion drastically while simultaneously preventing hydrophobic recovery of the PDMS surface. The findings provide a versatile means of surface functionalization of PDMS substrates and is suitable for many biomedical applications.