Protein Compatible Polymer Brushes on Polymeric Substrates Prepared by Surface-Initiated Transfer Radica Polymerization

Materials for insulin containers and delivery systems should comply with requirements like compatibility with proteins, sterilisability, 'good barrier properties towards preservatives, and no toxic leachables. The number of commercially available polymer materials which can be u sed is rather limited.

Therefore, a polymer coating containing some of the required properties may expand the use ofpolymers in medical devices. 'The approach was to graft polymer brushes from initiator-functionalized substrates using Surface-Initiated Atom TnlJlsfer Radical Polymerization (SI ATRP). Initial studies have been made with model systems of poly(ether ether ketone) (PEEK) films as they can easily be functionalized [1].

Moreover, the inert material polypropylene has successfully beel! activated using a photochemical method [2]. Different polymers including PEG-like matenals have been investigated as coating materials. ATR FTIR, water contact angle measurements, Thermal Gravimetric Analysis (TGA), and X-ray Photoelectron Spectroscopy (XPS) confirmed that hydrophilic polymers have been grafted from the surface.

The surface topography which was evaluated by Atomic Force Microscopy (AFM) did not change when the PEEK films were modified. The surface roughness should either be unchanged or decreased as it 'will affect the protein adsorption [3]. 1. O. Noiset, C. Henneuse, Y.-J. Schneider, J. Marchand-Brynaert Macromolecules 30 (1997) 540-548 2.

J. Huang, H. Murata, R.R. Koepsel, A.J. Russell, K. Matyjaszewski Biomacromolecules 8 (2007) 1396-1399 3. A.F. von Recum, T.~~. van KootenJ Biomat Sci-Polym E 7 (1995) 181-198.