Effect of surface properties on protein adsorption of polyurethane membranes

Objectives: Surface properties of biomaterials play a vital role in their functionality. It has already been established that the initial rapid adsorption of proteins onto the biomaterials surface is of paramount importance in the long-term results of guided tissue regeneration (GTR) therapy. In contrast surface energy will affect adhesion between biomaterial and surrounded tissue which is a challenge in GTR treatment. In this study, the effect of surface properties of polyurethane membrane on protein absorption has been investigated by using contact angle measurement, FTIR and Raman spectroscopy.

Methods: Polyether polyurethane and PDMS containing polyurethanes were synthesised via two step, solution polymerization. Monomers used in this study were Polytetramethylene oxide (PTMO), hydroxyl terminated polydimethylsiloxane (PDMS) and 4,4'-methylene diphenyl diisocyanate (MDI), chain extended with 1,4-butane diol (BDO). Synthesised polymers were characterised using FTIR and Raman spectroscopy. Surface energy and wettability of polymeric membranes were determined by contact angle measurement. Synthetic membranes were soaked in Bovine Serum Albumin (BSA) solutions, (0.3mg/ml) in non-ionized water. Protein absorption of membranes was investigated using Raman and ATR-FTIR spectroscopy.

Results: PDMS containing polyurethane showed lower surface energy (28.047mN/m) in comparison with unmodified polyether urethane (35.608mN/m) so it could be considered as a hydrophobic surface. IR spectra were significantly informative, as changes observed in Amide I and II bands of proteins indicated that more proteins adsorb onto surface of the polyetherurethane membranes in comparison to PDMS containing polyurethane.

Conclusion: It was concluded that incorporation of PDMS in polyurethane will reduce protein absorption as well as reducing adhesion to surrounding tissue.