Graphene Sensor Arrays for Rapid and Accurate Detection of Pancreatic Cancer Exosomes in Patients’ Blood Plasma Samples

Abstract

Biosensors based on graphene field effect transistors (GFETs) have the potential to enable the development of point-of-care diagnostic tools for early stage disease detection. However, issues with reproducibility and manufacturing yields of graphene sensors, but also with Debye screening and unwanted detection of nonspecific species, have prevented the wider clinical use of graphene technology. Here, we demonstrate that our wafer-scalable GFETs array platform enables meaningful clinical results. As a case study of high clinical relevance, we demonstrate an accurate and robust portable GFET array biosensor platform for the detection of pancreatic ductal adenocarcinoma (PDAC) in patients’ plasma through specific exosomes (GPC-1 expression) within 45 min. In order to facilitate reproducible detection in blood plasma, we optimized the analytical performance of GFET biosensors via the application of an internal control channel and the development of an optimized test protocol. Based on samples from 18 PDAC patients and 8 healthy controls, the GFET biosensor arrays could accurately discriminate between the two groups while being able to detect early cancer stages including stages 1 and 2. Furthermore, we confirmed the higher expression of GPC-1 and found that the concentration in PDAC plasma was on average more than 1 order of magnitude higher than in healthy samples. We found that these characteristics of GPC-1 cancerous exosomes are responsible for an increase in the number of target exosomes on the surface of graphene, leading to an improved signal response of the GFET biosensors. This GFET biosensor platform holds great promise for the development of an accurate tool for the rapid diagnosis of pancreatic cancer.

Detection of medically relevant volatile organic compounds with graphene field-effect transistors and separated by low-frequency spectral and time signatures

“…The end terminations of each metal pad (drain, source, and gate) located at the edge of the chip array were wire-bonded to a supporting printed circuit board (PCB) using a TPT HB wire bonder machine with a 50 μm thick Au wire. Electrical performance metrics obtained from the combination of this GFET chip array and a readout system (to be introduced in the following sections) have shown similarities to the curves provided by the manufacturer, namely the typical I DS – V DS linear profile and the transfer curve ( R DS – V GS ), the latter measured in PBS solution (thus yielding an electrolyte-based GFET sensing unit with top-gating 4,16 ).…”

“…In the medical field, GFET sensors or devices have already permitted the monitoring of disease biomarkers in cancer, 3,13,14 as well as respiratory, immunologic, neurodegenerative, 6,15 cancer 16 and infectious 17 conditions due in part to the ability of immobilizing antibodies, aptamers, or other molecules at the surface of graphene that bind to specific biological targets. However, functionalization of graphene with ligand molecules can involve multiple chemical steps that are both laborious and time-consuming, without the guarantee that non-specific adsorption of contaminant molecules will degrade sensor performance, or worse, destroy the graphene layer and associated materials, therefore making it impossible to re-use the sensing unit, especially in electrolyte-based GFETs.…”

A Panorama of Extracellular Vesicle Applications: From Biomarker Detection to Therapeutics

“…Similarly, another study used a 96-well electrochemical assay platform to analyze signals produced by antibody coated magnetic beads that were specific for selected EV biomarker targets . A field-effect transistor (FET) electrochemical assay employing an integrated antibody-conjugated 2D graphene functionalized gate electrode (carrier mobility >2000 cm 2 V s –1 ) has also been used to detect a biomarker-positive EV population in plasma samples . This approach employs high quality graphene that is grown by chemical vapor deposition to generate sensitive and inexpensive sensors that can be produced at scale.…”

Review—Prospects in Cancer Diagnosis: Exosome-Chip for Liquid Biopsy

“…This portable sensor could replace the gold standard in cancer diagnostics as it demonstrated clinical testing in plasma samples. 110 One of the interesting works for multiple exosome detection in clinical patient samples has been investigated by Zhang et al The exosome profiling platform (ExoProfile chip) was fabricated with the 3D nanostructures of patterned colloidal self-assembly for exosome immunophenotyping. This ExoProfile chip is multiplex and allows multiple analyte detection.…”