Perspective of Using Vertically Oriented Graphene as an Electrochemical Biosensing Platform

Electrochemical sensors based on vertically oriented graphene (VG) have gained attention in recent years due to the unique properties of VG, such as its large surface area, biocompatibility, and high electrical conductivity. In this paper, we studied an electrochemical sensor with interdigitated electrodes modified with VG as an essential interface for the identification of two types of human colon adenocarcinoma cells: SW403 (high invasiveness) and HT29 (low invasiveness). Both cell lines have epithelial morphology, and we tested the electrochemical sensor on different concentrations of SW403 and HT29 cells. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for morphological characterization of VG deposited on the working interdigitated electrodes, Raman spectroscopy was used to evaluate the graphitic nature of the VG growth on electrodes, and atomic force microscopy (AFM) was used to study the rugosity of the VG. Fourier-transform infrared spectrometry (FTIR) was used to study the configurations of the chemical bonds in the VG used for the working electrode of the electrochemical sensor. Vertically oriented graphene improves the sensor's response on the cell lines, as evaluated by electrochemical impedance spectroscopy (EIS).