Fabrication and in vitro characterization of porous biodegradable composites based on phosphate glasses and oligolactide-containing polymer networks Delia S. Brauer, 1 Christian Ru ¨ ssel, 2 Sebastian Vogt, 3 Ju ¨ rgen Weisser, 3 Matthias Schnabelrauch 3 1 Department of Preventive and Restorative Dental Sciences, University of California San Francisco, 707 Parnassus Avenue, San Francisco, California 94143 2 Otto-Schott-Institut, Friedrich-Schiller-Universita ¨t Jena, Fraunhoferstr. 6, D-07743 Jena, Germany 3 INNOVENT e.V., Biomaterials Department, Pru ¨ ssingstr. 27B, D-07745 Jena, Germany Received 26 October 2005; revised 15 February 2006; accepted 18 April 2006 Published online 29 September 2006 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jbm.a.30902 Abstract: Degradable porous composite materials for use as temporary bone replacement or tissue engineering scaf- folds were produced using a methacrylate-modified oligo- lactide polymer network and phosphate invert glasses in the system P 2 O 5 –CaO–MgO–Na 2 O–(TiO 2 ). Porous glasses with an open interconnective porosity were produced by a salt sintering process. Compressive strengths were signifi- cantly enhanced by polymer coating of the inner surface of the porous glasses or by fabrication of glass powder-rein- forced porous polymer specimens. In vitro degradation in simulated body fluid showed a degradation pattern of the composites which could be modulated by the composition and resulting solubility of the incorporated glass phase. Cytocompatibility of the composites was investigated in a FDA/EtBr viability assay using an MC3T3-E1 osteoblast- like cell line and showed good biocompatibility of the materials in vitro. Ó 2006 Wiley Periodicals, Inc. J Biomed Mater Res 80A: 410–420, 2007 Key words: composite; phosphate glass; degradation; bone regeneration; osteoblast INTRODUCTION Large bone defects due to trauma or tumor resec- tion create needs for synthetic bone replacement materials, which eliminate the need for donor bone. Porous biomaterials are of special interest for use as synthetic bone substitutes, as they allow for the in- growth of cells and tissue offshoots into the cavities, thereby establishing bonds that in corresponding nonporous devices would be developed only super- ficially. 1–3 However, in many cases the regeneration of bone is favored over bone replacement. Resorb- able porous implant materials can support this re- generation by bridging large defects. The porosity of the implant can act as a guide rail for the new bone growing in, and resorption of the implant materials begins simultaneously. For successful application, degradable porous im- plants should meet certain requirements. They need to be biocompatible, their rate of degradation should closely match the rate of tissue replacement and their mechanical properties should match those of the tissues at the implantation site. Furthermore, it should be possible to process the scaffolds into a va- riety of shapes. Over the last decades, ceramics, glasses, and glass- ceramics have opened new possibilities in the de- velopment of implant materials, as their chemical compositions can be adjusted to obtain the desired properties. 4–6 Glasses are an interesting range of mate- rials, especially for the development of degradable materials for use as temporary implants or tissue engineering material. Phosphate glasses have been increasingly studied for biomaterial applications, as they dissolve in aqueous media and their degradation rate can easily be adjusted by altering their composi- tion. 7–10 Furthermore, their composition is similar to that of the mineral phase of bone, which makes them potentially useful for promoting the regeneration of soft as well as hard connective tissue. However, in comparison with metals and poly- mers, glasses do not offer adjusted mechanical prop- Correspondence to: D. S. Brauer; e-mail: delia.brauer@ucsf. edu, delia.brauer@web.de Contract grant sponsor: Ministry of Science, Research and Art of Thuringia, Germany; contract grant number: B 478-02001 ' 2006 Wiley Periodicals, Inc.