In this paper, an electromagnetic characterization of a moveable wire electrode microchamber for nanosecond pulse delivery is proposed. The characterization of the exposure system was carried out through experimental measurements and numerical simulations. The frequency and time domain analyses demonstrate the utility of the proposed assembly for delivering pulses as short as 2.5 ns. High-voltage measurements (~1.2 kV) were also performed using pulse generators based on two different technologies with applied pulse durations of 5.0 and 2.5 ns. Validation of the delivery system was accomplished with biological experiments involving cell electroporation with 2.5 and 5.0 ns, 10-MV/m pulsed electric fields. A dose-dependent area increase (osmotic swelling) of the Jurkat cells was observed with pulses as short as 2.5 ns.