Mechanical properties and cell cultural response of polycaprolactone scaffolds designed and fabricated via fused deposition modeling

A number of different processing techniques have been developed to design a nd fabricate three-dimensional (3D) scaffolds for tissue-engineering applic ations. The imperfection of the current techniques has encouraged the use o f a rapid prototyping technology known as fused deposition modeling (FDM). Our results show that FDM allows the design and fabrication of highly repro ducible bioresorbable 3D scaffolds with a fully interconnected pore network . The mechanical properties and in vitro biocompatibility of polycaprolacto ne scaffolds with a porosity of 61 +/- 1% and two matrix architectures were studied. The honeycomblike pores had a size falling within the range of 36 0 x 430 x 620 mum. The scaffolds with a 0/60/120 degrees lay-down pattern h ad a compressive stiffness and a 1% offset yield strength in air of 41.9 +/ - 3.5 and 3.1 +/- 0.1 MPa, respectively, and a compressive stiffness and a 1% offset yield strength in simulated physiological conditions (a saline so lution at 37 degreesC) of 29.4 +/- 4.0 and 2.3 +/- 0.2 MPa, respectively. I n comparison, the scaffolds with a 0/72/144/36/108 degrees lay-down pattern had a compressive stiffness and a 1% offset yield strength in air of 20.2 +/- 1.7 and 2.4 +/- 0.1 MPa, respectively, and a compressive stiffness and a 1% offset yield strength in simulated physiological conditions (a saline solution at 37 degreesC) of 21.5 +/- 2.9 and 2.0 +/- 0.2 MPa, respectively. Statistical analysis confirmed that the five-angle scaffolds had significa ntly lower stiffness and 1% offset yield strengths under compression loadin g than those with a three-angle pattern under both testing conditions (p le ss than or equal to 0.05). The obtained stress-strain curves for both scaff old architectures demonstrate the typical behavior of a honeycomb structure undergoing deformation. In vitro studies were conducted with primary human fibroblasts and periosteal cells. Light, environmental scanning electron, and confocal laser microscopy as well as immunohistochemistry showed cell p roliferation and extracellular matrix production on the polycaprolactone su rface in the Ist culturing week. Over a period of 3-4 weeks in a culture, t he fully interconnected scaffold architecture was completely 3D-filled by c ellular tissue. Our cell culture study shows that fibroblasts and osteoblas t-like cells can proliferate, differentiate, and produce a cellular tissue in an entirely interconnected 3D polycaprolactone matrix. (C) 2001 John Wil ey & Sons, Inc.