Chitosan/Poly(3-caprolactone) blend scaffolds for cartilage repair Sara C. Neves a, b , Liliana S. Moreira Teixeira c , Lorenzo Moroni c , Rui L. Reis a, b , Clemens A. Van Blitterswijk c , Natália M. Alves a, b , Marcel Karperien c , João F. Mano a, b, * a 3B’s Research Group e Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Department of Polymer Engineering, University of Minho, AvePark, Zona Industrial da Gandra, S. Cláudio do Barco 4806-909, Caldas das Taipas, Guimarães, Portugal b IBB e Institute for Biotechnology and Bioengineering, PT Associated Laboratory, Guimarães, Portugal c MIRA e Institute for BioMedical Technology and Technical Medicine, University of Twente, Department of Tissue Regeneration, P.O. Box 217, Enschede 7500 AE, The Netherlands article info Article history: Received 23 July 2010 Accepted 19 September 2010 Available online 27 October 2010 Keywords: Chitosan Polycaprolactone Scaffold Cartilage tissue engineering abstract Chitosan (CHT)/poly(3-caprolactone) (PCL) blend 3D fiber-mesh scaffolds were studied as possible support structures for articular cartilage tissue (ACT) repair. Micro-fibers were obtained by wet-spinning of three different polymeric solutions: 100:0 (100CHT), 75:25 (75CHT) and 50:50 (50CHT) wt.% CHT/PCL, using a common solvent solution of 100 vol.% of formic acid. Scanning electron microscopy (SEM) analysis showed a homogeneous surface distribution of PCL. PCL was well dispersed throughout the CHT phase as analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. The fibers were folded into cylindrical moulds and underwent a thermal treatment to obtain the scaffolds. mCT analysis revealed an adequate porosity, pore size and interconnectivity for tissue engineering applications. The PCL component led to a higher fiber surface roughness, decreased the scaffolds swelling ratio and increased their compressive mechanical properties. Biological assays were performed after culturing bovine articular chondrocytes up to 21 days. SEM analysis, live-dead and metabolic activity assays showed that cells attached, proliferated, and were metabolically active over all scaffolds formu- lations. Cartilaginous extracellular matrix (ECM) formation was observed in all formulations. The 75CHT scaffolds supported the most neo-cartilage formation, as demonstrated by an increase in glycosamino- glycan production. In contrast to 100CHT scaffolds, ECM was homogenously deposited on the 75CHT and 50CHT scaffolds. Although mechanical properties of the 50CHT scaffold were better, the 75CHT scaffold facilitated better neo-cartilage formation. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Articular cartilage (AC) regeneration using tissue engineering (TE) approaches has been primarily proposed due to its limited capacity of self-repair [1,2]. This mainly derives from the lack of a vasculature network, resulting in insufficient turn-over of healthy chondrocytes to the defective sites and low productivity of char- acteristic proteins of the surrounding extracellular matrix (ECM) [1,2]. Three-dimensional (3D) scaffolds are particularly important for AC TE approaches because the chondrogenic phenotype is maintained when chondrocytes are placed in a proper 3D envi- ronment [2]. Cartilage-specific ECM components play an important role in regulating expression of the chondrogenic phenotype and sup- porting chondrogenesis [3,4]. Chitosan (CHT), a naturally derived polysaccharide, is an excellent candidate as AC TE scaffolding biomaterial, due to its structural similarity with various glycos- aminoglycans (GAGs) found in cartilage [5]. It was shown to support chondrogenic activity [5] and to allow cartilage ECM proteins expression by chondrocytes [6,7]. However, the brittleness in the wet state (40e50% of strain at break) of CHT scaffolds [8] is a major drawback for application in AC TE. Among synthetic biomaterials, poly(3-caprolactone) (PCL) is highly appealing due to its (a) physical-chemical and mechanical characteristics [9], (b) easy process ability related to a relatively low melting temperature (ca. 60  C) [8], (c) non-toxic degradation products and (d) Food and Drug Administration (FDA) approval for biomedical applications [9]. It has been previously reported that chondrocytes attach and proliferate on PCL films [10] and, addi- tionally, start to produce a cartilaginous ECM in PCL scaffolds [11,12]. However, PCL main drawbacks as scaffolding material * Corresponding author. 3B’s Research Group e Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engi- neering and Regenerative Medicine, Department of Polymer Engineering, University of Minho, AvePark, Zona Industrial da Gandra, S. Cláudio do Barco 4806-909, Caldas das Taipas, Guimarães, Portugal. Tel.: þ351 253510904; fax: þ351 253510909. E-mail address: jmano@dep.uminho.pt (J.F. Mano). Contents lists available at ScienceDirect Biomaterials journal homepage: www.elsevier.com/locate/biomaterials 0142-9612/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.biomaterials.2010.09.073 Biomaterials 32 (2011) 1068e1079