In dental practice, membranes are used as a barrier to prevent soft tissue ingrowth and create space for slowly regenerating periodontal and bony tissues. The aim of this study was to develop a biodegradable membrane system which can be used for guided tissue or bone regeneration. Three types of composite fibrous membranes based on nano-apatite (nAp) and poly(epsilon-caprolactone) (PCL) were made by electrospinning, i.e. n0 (nAp:PCL = 0:100), n25 (nAp:PCL = 25:100) and n50 (nAp:PCL = 50:100) with average fiber diameters ranging from 320 to 430 nm. Their structural, mechanical, chemical and biological properties were evaluated. Tensile test revealed that n25 had the highest strength and toughness, indicating there is an optimal ratio of nAp to polymer for mechanical reinforcement. Subsequently, a simulated body fluid immersion test confirmed that the presence of nAp enhanced the bioactive behavior of the membranes. Finally, an in vitro osteoblast cell study showed that all membranes supported proliferation, but the presence of nAp facilitated an early cell differentiation. This study demonstrated that an electrospun membrane incorporating nAp is strong, enhances bioactivity and supports osteoblast-like cell proliferation and differentiation. The membrane system can be used as a prototype for the further development of an optimal membrane for clinical use. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.