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. 2025 Mar 24;15(4):207.
doi: 10.3390/bios15040207.

A Planar-Gate Graphene Field-Effect Transistor Integrated Portable Platform for Rapid Detection of Colon Cancer-Derived Exosomes

Zaiyu Zhang  1 , Luyang Zhang  1 , Yuting Huang  2   3 , Ziran Wang  1 , Zhongjing Ren  1
Affiliations

A Planar-Gate Graphene Field-Effect Transistor Integrated Portable Platform for Rapid Detection of Colon Cancer-Derived Exosomes

Zaiyu Zhang et al. Biosensors (Basel). .

Abstract

Early diagnosis of diseases would significantly increase the survival rate of cancer patients. However, current screening methods are complex and costly, making them unsuitable for rapid health diagnosis in daily life. Here, we develop a portable platform based on a planar-gate graphene field-effect transistor functionalized with polydopamine self-assembled film (PDA-GFET), capable of identifying colon cancer through the detection of EpCAM protein, which is expressed on colon cancer-derived exosomes, in clinical samples within 10 min. The PDA self-assembled film on the graphene and gate surface enhances the biosensor's functionalization area while suppressing non-specific adsorption, thereby achieving detection limits as low as 112 particles/mL. In addition, the PDA-GFET-based detection platform was used to identify EpCAM protein in real clinical samples from healthy individuals and colon cancer patients within 10 min, and the two showed significant differences (p < 0.001). Results indicate that the proposed PDA-GFET-based detection platform is expected to be a potential tool for the early diagnosis of colon cancer.

Keywords: GFET biosensor; colon cancer diagnosis; exosome detection; polydopamine.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
PDA-GFET-based detection platform. (a) The overall process of the PDA-GFET-based detection platform in clinical sample testing. (b) The planar-gate GFET functionalized for exosome detection using PDA and aptamer.
Figure 2
Figure 2
Characterization of PDA-GFET and exosomes. (a) Raman spectra of the bare graphene and after PDA modification. (b) EDS shows successful functionalization of PDA and aptamer. (c) Dirac curve response signal in functionalization processes. (d) Nanoparticle tracking analysis of purified exosomes.
Figure 3
Figure 3
Detection of colon cancer-derived exosomes in PBS. Photos of the planar-gate GFET with the Au planar gate (a) and a traditional-gate GFET with an external AgCl gate (b). The Dirac characteristic curve (c) and linear fitting (d) of the planar-gate PDA-GFET for exosome detection in PBS. The dashed line represents the average change of the Dirac point after 10 times measurements of the device in 1× PBS; the Dirac characteristic curve (e) and linear fitting (f) of the planar-gate PDA-GFET for exosome detection in PBS. The dashed line represents the average change of the Dirac point after 10 times measurements of the device in 1× PBS.
Figure 4
Figure 4
The PDA-GFET-based detection platform detects exosomes at different concentrations in undiluted FBS with its Dirac characteristic curve (a) and linear fitting (b).
Figure 5
Figure 5
PDA-GFET-based detection platform for clinical sample detection in colon cancer patients. (a) Field test photo of the PDA-GFET-based detection platform; Dirac response curves of healthy samples (b) and colon cancer samples (c); (d) Analysis of the significant difference in response signals between healthy samples and colon cancer samples (*** represents p < 0.001).
See this image and copyright information in PMC

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