We present in this paper a new CMOS interface for cell manipulation by dielectrophoresis and capacitive sensing system dedicated for a lab-on-a-chip. It fully integrates a signal generation circuit and a post-processing system to control parameters of each signal such as frequency, phase and amplitude. In addition, a large capacitive and low resistive load driver circuit is designed to deliver a current of 9 mA for each 16 electrodes as the microfluidic architecture is divided into 4 blocs containing 16 electrodes each one. Thus, the proposed CMOS chip provides 4-channel signals with individually controllable phase and amplitude. In addition, a capacitive sensing system has been integrated into the same chip to detect the capacitive change in the microchannel in the Lab-on-a-chip. The generated signals have a 2.5 peak-to-peak voltage range and 70 kHz frequency range while the detection system has a dynamic range of 1.5 V and a sensitivity of 11.8 fF/V.