An exemplary method of delivering drugs or vaccines includes applying a series of first electrical signals to an electrode to generate plasma. The first electrical pulses having a first duration, first voltage amplitude, and first rise time. Applying molecules, drugs or vaccines to an area of skin contacted by the plasma； and applying a series of second electrical signals to the electrode to generate plasma to contact the area of the skin. The second electrical pulses have a second duration, second voltage amplitude, and second rise time. The duration for the first electrical pulses is shorter than the duration for the second electrical pulses. The voltage amplitude of the second electrical pulses is larger than the first electrical pulses. The rise time of the second electrical pulses is shorter than the first electrical pulses.
