Low cost disposable medical sensor fabricated on glass, paper or plastics

A medical sensor, comprising:

• a base structure comprising a functionalized sensing area disposed on a first electrode pad and a reference sensing area disposed on a second electrode pad, the first and second electrode pads disposed on the base structure with the second electrode pad physically separated from the first electrode pad;
• a transistor having a gate connected to the second electrode pad of the base structure and a drain, the transistor physically separate from the first electrode pad;
• and
• a pulse generator that generates a drain pulse and a gate pulse synchronized with the drain pulse, the pulse generator comprising a first pulse generator output that supplies the gate pulse and a second pulse generator output that supplies the drain pulse, the first pulse generator output connected to the first electrode pad and the second pulse generator output connected to the drain, where the transistor produces a drain current in response to the synchronized drain and gate pulses applied to the first electrode pad of the base structure and the drain of the transistor, the drain current corresponding to an amount of a target present in a sample disposed on the base structure.