Bi-layered constructs based on poly(L-lactic acid) and starch for tissue engineering of osteochondral defects S. Ghosh a,c , J.C. Viana b,c , R.L. Reis a,c , J.F. Mano a,c, ⁎ a 3B's Research Group, Biomaterials, Biodegradables and Biomimetics, Campus de Gualtar, 4710–057 Braga, Portugal b IPC, Institute for Polymers and Composites, Campus de Azurém, 4800–058, Guimarães, Portugal c Department of Polymer Engineering, University of Minho, 4800–058, Guimarães, Portugal Received 6 December 2006; accepted 11 December 2006 Available online 18 January 2007 Abstract Articular cartilage has a limited capacity to repair itself, and conventional therapeutic approaches have shown to have limited success as they are deficient and inconsistent in long-term repair. Tissue engineering has shown to be an alternative route to regenerate articular defects. In this work, new bi-layered scaffolds are developed in order to enhance the integration between the engineered cartilage tissue and the corresponding subchondral bone. The concept includes the use of a common polymer in both sides, poly(L-lactic acid), PLLA, to increase the bonding between them, and the use of compression moulding followed by particle leaching to process porous scaffolds with controllable porosities. A compact layer could be observed between the two layers that could be useful for independent cell culturing of the developed osteochondral constructs. A blend of starch and PLLA was used in the cartilage side, which was found to possess adequate hydration capability. For the bone region, where more stiffness and strength was required, PLLA reinforced with hydroxyapatite was used. Preliminary bioactivity tests demonstrated that the bone-layer could induce the formation of a calcium–phosphate layer in vitro, whereas the cartilage layer does not exhibit the ability for calcification. © 2007 Published by Elsevier B.V. Keywords: Osteochondral scaffolds; Tissue engineering; Articular cartilage; Biodegradable polymers 1. Introduction The repair of articular cartilage, as a result of trauma, tumour resection or degeneration, remains an intractable problem, due to the poor natural healing capacity of this tissue owing to its avascular nature [1]. The new extra-cellular matrix synthesised by the chondrocytes and their proliferation, as a response to injury, does not completely repair the tissue defect and both processes will typically cease too soon [2]. There are now a range of surgical procedures and cell-based therapies that helps in delaying the need of joint replacing surgery. Those include resurfacing with periosteum or perichondrium [3,4], condrocyte [5–7], osteochondral [8] and mesenchymal stem cell transplan- tation [9]. However, it has been reported that these approaches are far to give a complete and long-term cartilage healing. Mosaicplasty is a surgical method that integrates well the subchondral bone into the host tissue, but has the disadvantages of limited amount of autogeneous tissue, elimination of healthy tissue and donor-site morbidity [10,11]. Tissue engineering approaches have great potential in the biological and functional regeneration of cartilage, allowing for overcoming the lack of donor tissue and to promote a biologically and mechanically functional tissue [12–16]. Adequate cell sources, ideally extracted from the own patient, should be supported within a three-dimensional scaffold, with a pre-defined size and shape, being subsequent implanted after sufficient extra-cellular matrix and cells have been produced in vitro. Despite the success in growing cartilage in vitro, the limited success in vivo results in part to the lack of integration with surrounding cartilage and subchondral bone. To improve integration, TE approaches have used multiphase constructs utilizing different materials and internal architectures, in which one region is designed to the repair of the cartilage whereas the other region will specifically integrate to the subchondral bone. Available online at www.sciencedirect.com Materials Science and Engineering C 28 (2008) 80 – 86 www.elsevier.com/locate/msec ⁎ Corresponding author. 3B's Research Group, Biomaterials, Biodegradables and Biomimetics, Campus de Gualtar, 4710–057 Braga, Portugal. E-mail address: jmano@dep.uminho.pt (J.F. Mano). 0928-4931/$ - see front matter © 2007 Published by Elsevier B.V. doi:10.1016/j.msec.2006.12.012