Adjustable implant with self-sealing elastomeric membrane and methods of fabrication thereof

An adjustable implant for volumetrically altering, replacing, expanding, or augmenting tissues comprising an elastomeric membrane enclosed or partially enclosed about a main chamber, which is adapted to expand when filled with a fluid,

• wherein the membrane comprises:
• an outer zone formed from at least one outer elastomeric layer;
• an inner zone formed from at least one inner elastomeric layer;
• and
• a middle zone formed from at least one elastomeric middle layer positioned between at least a portion of the outer zone and at least a portion of the inner zone, and
• wherein a volume enclosed by the middle zone at the time of curing is larger than each of a volume enclosed by the inner zone at the time of curing and a volume enclosed by the outer zone at the time of curing, resulting in compression of the middle zone by at least one of the outer zone and the inner zone wherein the membrane includes a first end and a second end positioned to form an opening for accessing an interior of the main chamber, and wherein a plug is provided in the opening.