the present invention relates to a membrane comprising at least one positively charged , synthetic , hydrophobic polymer , at least one hydrophilic polymer and at least one plasticizer ; wherein said membrane is flexible and is capable of supporting at least one of cell adherence , cell proliferation or cell differentiation . the invention further relates to use of a membrane of the invention in the preparation of an implantable devices including cell delivery systems , cell growing surfaces and scaffolds . the invention further provides methods for promoting tissue regeneration in a defected tissue region applying membranes of the invention .