An organic, charge-modulated field effect transistor for DNA detection

A novel DNA sensor able to detect the DNA hybridization in liquids is presented. The device is a charge sensor, realized with an organic field effect transistor, sensitive to the negatively charged DNA phosphates groups. Compared to other examples of DNA sensors based on organic transistors, this device has two noticeable features: the probe area is completely separated from the transistor area and the sensing mechanism is not reliant on the choice of the device materials. Moreover, the device architecture has been designed in order to avoid any damaging treatment that may reduce the stability of the organic semiconductor. These features make this device especially suitable for the realization of portable and low cost sensors. Two devices (one used as reference and the other as sensor) are measured at the same time in order to get rid of current drifts which are due to organic semiconductor degradation or bias stress, and to enhance variations induced by the DNA sensing mechanism.