Preparation and in vitro characterization of scaffolds of poly(L-lactic acid) containing bioactive glass ceramic nanoparticles Zhongkui Hong, Rui L. Reis, Joa ˜o F. Mano * University of Minho, 3B ´ s Research Group – Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, Campus de Gualtar, 4710-057 Braga, Portugal IBB – Institute for Biotechnology and Bioengineering, Braga, Portugal Received 30 November 2007; received in revised form 4 March 2008; accepted 20 March 2008 Available online 1 April 2008 Abstract Porous nanocomposite scaffolds of poly(L-lactic acid) (PLLA) containing different quantities of bioactive glass ceramic (BGC) nano- particles (SiO 2 :CaO:P 2 O 5  55:40:5 (mol)) were prepared by a thermally induced phase-separation method. Dioxane was used as the sol- vent for PLLA. Introduction of less than 20 wt.% of BGC nanoparticles did not remarkably affect the porosity of PLLA foam. However, as the BGC content increased to 30 wt.%, the porosity of the composite was observed to decrease rapidly. The compressive modulus of the scaffolds increased from 5.5 to 8.0 MPa, while the compressive strength increased from 0.28 to 0.35 MPa as the BGC content increased from 0 to 30 wt.%. The in vitro bioactivity and biodegradability of nanocomposites were investigated by incubation in simu- lated body fluid (SBF) and phosphate-buffered saline, respectively. Scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction were employed to monitor the surface variation of neat PLLA and PLLA/ BGC porous scaffolds during incubation. PLLA/(20 wt.%)BGC composite exhibited the best mineralization property in SBF, while the PLLA/(10 wt.%)BGC composite showed the highest water absorption ability. Ó 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Keywords: Nanocomposites; Poly(L-lactic acid); Bioactive glass ceramic; Bone tissue engineering; Scaffolds 1. Introduction Tissue engineering has been considered as a practical therapeutic approach towards the regeneration of human tissue [1]. Biomaterials for application in tissue engineering could guide cell attachment, cell proliferation and tissue regeneration when implanted at the desired site in the patient’s body. Composites of polymers and bioactive ceramics have attracted increasing attention as promising biomaterials for bone tissue engineering [2–4]. Three- dimensional (3D) porous composite scaffolds can induce the ingrowth of cell to the desired shape and may facilitate the vascularization of new generated tissue [5,6]. The desirable combination of biocompatibility of biode- gradable polymers and the bioactivity of bioceramics could be achieved by preparation of porous polymer/ceramic composites by different methods [7–11]. Numerous biodegradable polymers have been used in the preparation of polymer/ceramic composite. These poly- mer included poly(L-lactic acid) (PLLA) [2,10–18], poly(caprolactone) [4,19,20], poly(glycolic acid) [21], poly(glycolide-co-lactide) [22,23], poly(caprolactone-co- lactide) [24,25] and polysaccharides [3,26–29]. Some ceramics and glasses can directly bond to living bone without the formation of surrounding fibrous tissue. In such cases a bone-like apatite layer is deposited in vivo between the implant and bone [30]. This mineraliza- tion ability has been defined as bioactivity of biomaterial. Hydroxyapatite (HA), which constitutes the inorganic frac- tion of bone, has been considered to be a bioactive material 1742-7061/$ - see front matter Ó 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.actbio.2008.03.007 * Corresponding author. Tel.: +351 253604497/253510320. E-mail address: jmano@dep.uminho.pt (J.F. Mano). Available online at www.sciencedirect.com Acta Biomaterialia 4 (2008) 1297–1306 www.elsevier.com/locate/actabiomat