The improvement of surface treatment methods that permit the tuning of cell adhesion on the surface of biomaterials and devices is of considerable importance. Here, multi-walled carbon nanotubes (MWCNT) were modified with 4-aminothiophenol (4ATP). Then, electrodeposition of MWCNT-4ATP was carried out on 4ATP-modified screen-printed gold electrodes (SP-Au). After conjugation of Arginyl-glycyl-aspartic acid (RGD)-peptide on Poly(MWCNT-4ATP), the adhesion of U-87MG glioblastoma cells was examined by differential pulse voltammetry (DPV) technique. The synthesized MWCNT-4ATP and the obtained Poly(MWCNT-4ATP)/RGD surfaces were characterized using Scanning Electron Microscopy-Energy Dispersive X-Ray Spectrometer (SEM-EDS), Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-Ray Photoelectron Spectrometer (XPS). The linear range for U-87MG glioblastoma cells was 10