Vertical Graphene-Based Biosensor for Tumor Cell Dielectric Signature Evaluation

Abstract

The selective and rapid detection of tumor cells is of critical consequence for the theragnostic field of tumorigenesis; conventional methods, such as histopathological diagnostic methods, often require a long analysis time, excessive analytical costs, complex operations, qualified personnel and deliver many false-positive results. We are considering a new approach of an electrochemical biosensor based on graphene, which is evidenced to be a revolutionary nanomaterial enabling the specific and selective capture of tumor cells. In this paper, we report a biosensor fabricated by growing vertically aligned graphene nanosheets on the conductive surface of interdigitated electrodes which is functionalized with anti-EpCAM antibodies. The dielectric signature of the three types of tumor cells is determined by correlating the values from the Nyquist and Bode diagram: charge transfer resistance, electrical double layer capacity, Debye length, characteristic relaxation times of mobile charges, diffusion/adsorption coefficients, and variation in the electrical permittivity complex and of the phase shift with frequency. These characteristics are strongly dependent on the type of membrane molecules and the electromagnetic resonance frequency. We were able to use the fabricated sensor to differentiate between three types of tumor cell lines, HT-29, SW403 and MCF-7, by dielectric signature. The proposed evaluation method showed the permittivity at 1 MHz to be 3.63 nF for SW403 cells, 4.97 nF for HT 29 cells and 6.9 nF for MCF-7 cells.

Vertical Graphene-Based Electrochemical Biosensor for Detection of Specific Chemotherapeutic Agents

“…The technological flow for the fabrication of the electrochemical sensor with IDE modified with vertical graphene is presented in our previous work [25]. The main steps of the flow consisted of: ( 1…”

“…The modified sensors were then tested by applying 10 µl of bleomycin (10 mM) to the active area of the sensors under the same conditions 2.2.3.2. Vertical graphene-based IDE Gold nanoparticles (AuNPs) were synthesized using a previously reported method [25] employing 0.3 mM HAuCl4 as a metal precursor and 1% sodium citrate as a reducing agent. To bind the thiolated DNA sequence on VG-based sensors, we decorated the carbonic nanomaterial with AuNPs (approximately 30 nm) through electrostatic interaction between the negative charge of nanoparticles and the positive amino group from the APTES structure.…”

“…The vertical graphene, acting as an active layer for the analyte of interest, demonstrated enhanced sensitivity, selectivity, minimal interference with biological matrices and prolonged stability. The electrochemical sensor was fabricated by growing vertically aligned graphene nanosheets on the conductive surface (Au) of interdigitated electrodes, and vertical graphene was decorated with gold nanoparticles (AuNPs) [25].…”

Characterization of Electrical Properties of 3d Printed Biosensors With Various Electrode Geometries

“…Six different active areas of the working electrode were used to vary the active area of the working electrode. Figure 6 presents the Nyquist plot for impedance response that shows the surface and volume diffusion competition coupled with the electric charge exchange processes [19,20]. From the data obtained from the Nyquist plot, an equivalent circuit model for a biosensor is created, Fig.…”

Perspective of Using Vertically Oriented Graphene as an Electrochemical Biosensing Platform

“…Burinaru et al introduced an electrochemical impedance spectroscopy biosensor in a microfluidic device for circulating tumor cell (CTC) detection [18]. Tincu et al developed a biosensor with vertically aligned nanosheets and anti-EpCAM antibodies [19].…”