Patent ID: 7361500

Claim:
An apparatus for electrically contacting biological cells suspended in a liquid, said apparatus comprising: a substrate having at least one opening, a suction channel ending in said opening, said suction channel being adapted to provide a first hydrodynamic low pressure at the opening for immobilizing a cell having a cell membrane on top of said opening, a contact unit being arranged below the opening and comprising a contact tip, and at least one electrode for electrically contacting the cell when it is immobilized on top of said opening, wherein the contact tip comprises a top end projecting into said opening in such a way that said contact tip comes to bear against the cell membrane when the cell is immobilized on top of said opening, and further comprises a contact channel which opens at the top end in such a way that a second hydro-dynamic low pressure can be exerted upon the cell membrane, and wherein the electrode is arranged within said contact channel, and wherein the contact unit has a replaceable top part comprising the contact tip and a reusable bottom part comprising the electrode and a first section of the contact channel, wherein the top part further comprises an annular recess formed around the contact tip and facing the substrate, with the annular recess having a passage connected to the suction channel.