Yes, you can target one or a small number of cells. The number of cells that you can target depends of the size of your target area. For complete exposure, the target area should not exceed the delivery zone size, that is created by the BioPen system.
You can adjust the size of the delivery zone via the BioPen software. The size of the delivery zone varies between:
20-160 μm in length 90-110 μm in width