Synthesis, structural and mechanical properties of porous polymeric scaffolds for bone tissue regeneration based on neat poly(ε-caprolactone) calcium carbonate

The aim of the present study was to develop new materials which could be applicable as bone substitutes or be used in bone tissue engineering. Two types of porous scaffolds based on poly(epsilon-caprolactone) (PCL) were investigated. Type 1 scaffolds were prepared by solvent casting/particulate leaching technique, using NaCl with the grain size 250-500 mu m as a porogen. In the case of Type 2 scaffolds, the biodegradable polymer was blended with calcium carbonate, which, in contrast to NaCl, is not leached out from the product during manufacture, either in the form of calcite powder or aragonite (needle-like crystals). Influence of manufacturing technique and initial substrate composition on product properties was investigated. The tests involved porosity measurements, structure analysis by optical and scanning electron microscopy and mechanical studies (determination of compression strength and modulus). The results indicate the important role of the phase exchange process in the formation of micropores. In this process PCL precipitated from its acetone solution in the presence of water creating microporous three-dimensional polymer structures. The Type 1 scaffolds possessed both micropores and macropores. Good interconnectivity between the pores was observed for samples of the initial porogen content higher than 33%. Microporous samples containing inorganic filler have lower porosity and higher compression strength. For Type 2 scaffolds the shape of filler particles has an important influence on mechanical properties-replacing powder with needle-like crystals (in the same weight amount) results in a three- to five-fold increase in compression modulus. (c) 2006 John Wiley & Sons, Ltd.