Glass-metal feedthrough

An element for insertion into or attachment to a human or animal body or biological living cells containing cell cultures, the element comprising:

• a glass-metal feedthrough comprising:
• an external conductor having a coefficient of expansion αexternal, and having an opening formed therein;
• an internal conductor disposed in the opening, the internal conductor comprising iron and having a coefficient of expansion αinternal, the external conductor and the internal conductor being configured to not release nickel when in contact with a human or animal body or biological cells of a cell culture;
• and
• a glass material surrounding the internal conductor within the opening and having a coefficient of expansion αglass, the coefficient of expansion of the internal conductor αinternal and the coefficient of expansion of the external conductor αexternal are such that a joint pressure on the internal conductor of at least 30 MPa is generated in a temperature range of 20° C. to a glass transformation temperature of the glass material.