A cell chip is a valuable tool to evaluate the effects of anticancer drugs, antibiotics and environmental toxicants on various kinds of cells. In this study, a conductive composite material composed of multi-walled carbon nanotubes (CNTs) and RGD-MAP-C peptide was fabricated on gold electrode surface for enhancing electrochemical signals from HEK293T cells. The topological characteristics and electrochemical performance of composite materials with different concentrations of CNTs were analyzed by scanning electron microscopy and cyclic voltammetry (CV), respectively. CNTs/RGD peptide composites (CP) electrode containing 20 microg/ml CNT was found to be excellent for improving the sensitivity of cell chip compared with that of bare gold or RGD peptide modified electrode. Finally, two kinds of nephrotoxic antibiotics were treated to HEK293T cells and their toxicity were successfully monitored by CV. Our CP composites can be used as a suitable conducting material for the fabrication of various kinds of cell-based chips.