The present invention provides an implantable bioreactor comprising cells enclosed within an enclosure, said cells being capable of producing paracrine factors, wherein the enclosure is collapsible or expandable or both or neither, wherein the enclosure is semipermeable such that it provides containment of the cells preventing the egress of the cells while further providing a barrier that shields the cells from immunological attack, and wherein the enclosure is permeable to the entire secretome of the cell including exosomes, nucleic acids and proteins. The implantable bioreactor can have various configurations and can house internally a cell culture matrix than can include hydrogels, microbeads, and nanofiber matrices along with other active agents.