Quantum dot (QD) gate FETs and the use of quantum dot (QD) gate FETs for the purpose of sensing analytes and proteins is disclosed and described. Analytes, proteins, miRNAs, and DNAs functionalized to the QDs change the charge density in the gate and hence the current-voltage characteristics. In one embodiment, QD-FETs, such as 3-state configurations, the binding of chemical and biological species change the drain current-gate voltage characteristics resulting in detection. In one embodiment, DNA sensing is done by its binding to an existing reference DNA functionalized on to quantum dots which are located in the gate region of the FET.