An artificial intervertebral disc and disc nucleus are described herein having chambers and dampening members. The dampening members may be within or outside of the main body of the device. The chambers may be filled with a suitable liquid, gas, or both, and separated by valves to regulate flow of fluid between chambers, within a dampening member, between the main body and dampening member, or all of the above. Chambers may be filled with responsive hydrogels, EPAM, or other suitable materials, and the device may have activation plates or members, a strain gauge, a pressure sensor, or other means for detecting changes in the materials and/or triggering desired changes in the materials in order to mimic the behavior of a healthy native disc or disc nucleus. A control system may be in communication with the device for receiving feedback and delivering stimuli to initiate desired changes in the fluids or other materials. Membranes may be of variable permeability and may be metallized to ensure as low permeability as possible. Dampening members may be filled during manufacture with carbon dioxide or other suitable gas which may be in a supercritical state and allowed to return to ambient temperature and gaseous state or by other means. Methods of manufacture, delivery of the artificial disc and related structures, and methods of treatment are also described.