There are some metals that are well known to be biocompatible, as in no immune response. The video in the article has diagram of the inner screws into her arm.

There are some metals that are well known to be biocompatible, as in no immune response. The video in the article has diagram of the inner screws into her arm. I'd guess the screws are Ti6Al4V, which is frequently used in knee replacements and other orthopedic surgeries.