Surface Modifications of Peot/pbt Copolymers for the Improvement of Bone Marrow Stromal Cell Attachment

s / 87 (2003) 199–308 299 interest. When injured, bone does not heal with a fibrous scar, as do virtually all other tissues. An attractive method of bone repair is to culture bone cells on polymer scaffolds in vitro and subsequently implant these artificial hybrid materials [2]. Interesting polymers for these scaffolds are PEOT/PBT block copolymers. The composition with 70 wt% PEO soft segment and PEO molecular weight 1000 (1000PEOT70PBT30) exhibits calcification and bone bonding properties after implantation in goats [3]. As discussed in the following, surface modification is necessary in order to in vitro culture cells on this copolymer composition. Besides important requirements like biocompatibility and biodegradability the implant also needs to be porous to allow for tissue ingrowth and stabilisation. Specifically interconnected pores larger than 200–400 mm and a minimum pore density of 75% are needed [4]. We aim at preparing PEO/PBT scaffolds varying in pore size (larger than 200 mm) and porosity (over 70%) for the tissue engineering of bone. To improve cell adhesion wet chemical and gas plasma treatments were studied. Experimental methods Materials Polymers were prepared by polycondensation as previously described [5]. Film preparation Films were solution cast from chloroform/hexafluoroisopropanol mixtures using a 750 mm casting knife or compression molded at 140 8C for 4 minutes. Porous scaffold preparation Typically mixtures of copolymer and sodium chloride particles (75–90 v%) of known sizes were compression molded in a hot press. The salt was leached out using demineralized water (4 days), followed by drying in a vacuum oven for 48 hours.