Master Bond MasterSil 151Med was used in research done by a scientist from Norwegian University of Science and Technology. Here is a quote from this work:
"The complete device must be encapsulated in a material that enables the user to change the power source, as well as to stay biocompatible. . . . The Master Bond silicone MasterSil 151Med was tested for water intrusion and easy removal . . . A moisture indicator paper was attached to the electrode pin conductors and inserted into a mold with the silicone. The sealing was then tested by being submerged in saline solution for 3 months. The result was that the silicone was completely sealed and fairly easy to remove, and is thus a simple and effective method for encapsulation."1
Sources:
1An Implantable Device for Electrical Nerve Stimulation. Lars Lyse Moen, thesis for Master of Science in Cybernetics. Norwegian University of Science and Technology, Department of Engineering Cybernetics, July 2014. http://daim.idi.ntnu.no/masteroppgaver/010/10757/masteroppgave.pdf