A glass-metal feedthrough includes: an external conductor including steel, having a coefficient of expansion αexternal, and having an opening formed therein; an internal conductor disposed in the opening, the internal conductor including steel and having a coefficient of expansion αinternal. The external conductor and the internal conductor are configured to not release nickel when in contact with a human or animal body or biological cells of a cell culture. A glass material surrounds the internal conductor within the opening and has a coefficient of expansion αglass. The coefficient of expansion αexternal of the external conductor and the coefficient of expansion αinternal of the internal conductor both are greater than the coefficient of expansion αglass of the glass material.