In present study, an efficient solvent-free foaming method aided by supercritical carbon dioxide (sc-CO2) is developed to prepare porous PLGA/PCL bilayer membranes for potential guided tissue regeneration (GTR) applications. First rheological properties and foaming behaviors of PLGA and PCL were studied in detail. Compared with PLGA, PCL had lower viscosity with loss tangent tan delta over 1 thus got bigger and highly interconnected pores after foaming. Based on this, membranes with distinct porous PCL and PLGA bilayer were prepared via a one-step foaming. SEM showed the pore size of the PCL layer was 80-100 mu m, and that of the PLGA layer was less than 10 mu m. Through tensile tests these membranes exhibited a tensile strength of 4.02 MPa and a elongation at break of 57.7 %, meeting the mechanical requirements of GTR. Further cell tests demonstrated that the PCL layer suited for the proliferation of osteoblasts and the PLGA layer inhibited the ingrowth of fibroblasts. The porous PLGA/PCL bilayer membranes fabricated using this one-step foaming meet the requirements of GTR and possess great commercial potential. (C) 2018 Elsevier B.V. All rights reserved.