The role of hydroxyapatite as solid signal on performance of PCL porous scaffolds for bone tissue regeneration

Abstract Highly porous composites made up of biodegradable poly‐ε‐caprolactone (PCL) and stoichiometric hydroxyapatite (HA) particles have been developed as substrate for bone‐tissue regeneration. The processing technique consists of phase inversion and particulate (salt crystals) leaching. Three different HA contents (13, 20 and 26 vol %) in PCL‐based composite were considered in this study. Pore microstructure with fully interconnected network and pore sizes ranging around a few hundred of μm (macroporosity) was obtained as a result of salt particles removal by leaching process. Several microns (microporosity) porosity was also created through phase inversion of polymer solution. Total porosity up to 95% was achieved. Human marrow stromal cells (MSC) were seeded onto porous PCL‐based composites for 1–5 weeks and cultured in osteogenic medium. MSC were able to adhere and grow on PCL‐based substrates with a plateau at 3–4 weeks. However, the small effect of bioactive signals on the biological response evaluated in MSC cell culture suggests a prior role of topography on the biological response. Importantly, the presence of HA as a bioactive solid signal determines an increase of mechanical properties. On the overall, the results indicated that porous PCL‐based composites are potential candidate for bone substitution with beneficial influence on structural characteristics by solid signal addition. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008