The dynamic processes occurring in microscopic, mesoscopic, and macroscopic organisms play key roles in device sensing and can be effectively monitored by impedance characterization. Graphene and its derivatives have attracted much attention for potential applications in biological sensing systems because of their unique 2D structural, surface and electronic properties. In this work, on-chip integrated impedance bio-sensors are demonstrated using coplanar waveguides (CPWs) as the sensing platform. Absorption of Chitoson and DNA on graphene /graphene derivatives leads to remarkable red-shift of the resonant frequencies. Substrate complex permittivity is extracted from momentum simulations. The imaginary part of the permittivity indicates significant leakage currents in the graphene/graphene derivatives, Chitoson, and DNA. © 2011 IEEE.