The adhesion and proliferation of fibroblast onto the surface of an implant biomedical device can lead to fibrous tissue encapsulation. The fibrous encapsulation can be detrimental to various implant applications, such as drug delivery devices. Therefore, the development of a nonfouling surface is necessary for the implantable drug delivery devices.

Poly(ethylene glycol) (PEG) is a nontoxic and nonimmunogenic polymer. PEG has the ability to inhibit cell adhesion on a surface due to its hydrophilicity, steric hindrance, and chain mobility. To produce a nonfouling surface, a new method was proposed for grafting PEG on the polycaprolactone (PCL) porous membrane surface. In this study, PEG(400)-monoacrylate was pre-coated on the PCL membrane surface. By using oxygen plasma, PEG could be successfully bonded on the PCL membrane.

The operating condition of the oxygen plasma was optimized to prevent fibroblast adhesion. When the membrane was treated with soaking in a 0.1M PEG (Mw 400)-monoacrylate solution and the oxygen plasma of 25W power for 5 seconds, there was around 90% less number of fibroblast attached onto the PEG-grafted PCL porous membrane than the untreated membrane surface. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) showed that the intensity of a PEG characteristic peak (~1100 cm-1) increased significantly for the (Mw 400)-grafted membrane. Moreover, the contact angle for the PEG (Mw 400)-grafted surface was decreased significantly in comparison with the untreated membrane. Therefore, the anti-biofouling surface of the PEG-grafted PCL porous membrane can be obtained for the implant drug delivery devices.