We report a novel interdigital sensor and actuator device based on branched tree-like carbon nanotubes (CNT) on silicon-based membranes with a high capacitance value. The presence of tree-like CNTs leads to a high overlap between interdigital fingers owing to their three dimensional nanometric features, hence increasing the value of the capacitance from 0.2 to 15 pF. The electromechanical behavior of the device has been investigated with monitoring capacitive characteristics of the sensor. An almost linear rise in the capacitance value by applying the external voltage is observed which could be due to the modulated overlapping between neighboring electrodes. The response of the sensor/actuator device to various frequencies has been studied.