An implantable medical device, a method of manufacturing, and a method of use are described. The implantable medical device includes an absorption bag connected by a cannula to a discharge bag. The implantable medical device also includes a reservoir external to the discharge bag and attached to a surface of the discharge bag. At least a portion of the absorption bag and at least a portion of a bottom surface of the reservoir are permeable to a predefined class of small molecules, such as molecular oxygen. The reservoir can retain live cells that rely on the small molecules for survival and growth. Based on concentration of the small molecules, the small molecules permeate into the absorption bag and are transported to the discharge bag for permeation into the reservoir, thereby providing a supply of the small molecules to the live cells.