Biomaterials 23 (2002) 1169–1185 Fused deposition modeling of novel scaffold architectures for tissue engineering applications Iwan Zein a , Dietmar W. Hutmacher b, *, Kim Cheng Tan c , Swee Hin Teoh a a Laboratory for Biomedical Engineering (LBME), E305-16, Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore b Department of Orthopaedic Surgery, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074, Singapore c Temasek Engineering School, Temasek Polytechnic, 21 Tampines Avenue 1, Singapore, 529757, Singapore Received 13 November 2000; accepted 22 June 2001 Abstract Fused deposition modeling, a rapid prototyping technology, was used to produce novel scaffolds with honeycomb-like pattern, fully interconnected channel network, and controllable porosity and channel size. A bioresorbable polymer poly(e-caprolactone) (PCL) was developed as a filament modeling material to produce porous scaffolds, made of layers of directionally aligned microfilaments, using this computer-controlled extrusion and deposition process. The PCL scaffolds were produced with a range of channel size 160–700 mm, filament diameter 260–370 mm and porosity 48–77%, and regular geometrical honeycomb pores, depending on the processing parameters. The scaffolds of different porosity also exhibited a pattern of compressive stress–strain behavior characteristic of porous solids under such loading. The compressive stiffness ranged from 4 to 77 MPa, yield strength from 0.4 to 3.6MPa and yield strain from 4% to 28%. Analysis of the measured data shows a high correlation between the scaffold porosity and the compressive properties based on a power–law relationship. r 2001 Elsevier Science Ltd. All rights reserved. Keywords: Tissue engineering; Scaffold; Fused deposition modeling; Bioresorbable polymer; Porosity; Interconnected channel network; Compressive properties 1. Introduction Different processing techniques have been developed to build scaffolds for tissue engineered constructs [1,2]. These conventional techniques include fiber-bonding, solvent casting and particulate leaching, membrane lamination, melt molding, thermally induced phase separation and gas foaming. None of these conventional techniques has allowed researchers to build scaffoldsF with a completely interconnected pore network with large interconnection channels, a highly regular and reproducible scaffold morphologyFby using a compu- ter-controlled design and fabrication process [2]. The imperfection of the conventional techniques has encour- aged the use of a rapid prototyping (RP) technology, also known as solid freeform fabrication (SFF) technol- ogy, in the scaffold design and fabrication stages of tissue engineering. At present, there are a number of RP techniques that have been reported on fabrication of bioresorbable scaffolds. Three-dimensional printing (3DP) led the group with the most publications as a new method of scaffold fabrication using poly(lactic acid) and poly(lactic-co-glycolic acid) [3–5]. The 3DP method requires the use of organic solvents as binder for the powder-based aliphatic polyesters. The other two methods reported recently are known as multi-phase jet solidification [6] and shape deposition manufacturing [7,8]. Our group has applied fused deposition modeling (FDM) [9] to design and fabricate bioresorbable scaffolds with a fully interconnected channel network. In comparison with other SFF techniques, the FDM method does not require any solvent and offers great ease and flexibility in material handling and processing. The use of a filament modeling material also reduces its residence time in the heating compartment and allows continuous production without the need of replacing feedstock. *Corresponding author. 0142-9612/02/$-see front matter r 2001 Elsevier Science Ltd. All rights reserved. PII:S0142-9612(01)00232-0