A method for producing an implant, the method includes providing a hollow biocompatible shell to be implanted in an organ of a patient. At least two filling materials are injected at one or more locations in the shell, such that a mixture of at least two of the filling materials is configured to produce gas bubbles within a bulk of the mixture. The gas bubbles are formed in the injected filling materials by heating the shell containing the mixture of the injected filling materials.
