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Development of Electrochemical-based Immunosensor for
Colorectal Cancer Biomarker Detection in Serum and Stool
Pimporn Roeksrungruang1*, Deanpen Japrung2, Kanitha Patarakul1
1 Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University
2 National Nanotechnology Center, National Science and Technology Development Agency, Thailand
Science Park
3 Department of Microbiology, Faculty of Medicine, Chulalongkorn University
*Corresponding Author E-mail: pimmy5205085@gmail.com
Background: Abstract
Although the fecal immunochemical test (FIT) is available for home colorectal cancer (CRC)
screening, it demonstrates high sensitivity and specificity for detecting advanced cancers.
Serum carcinoembryonic antigen (SCEA) is useful for monitoring treatment response and
recurrence in diagnosed CRC patients. Recently, some studies have shown that fecal CEA
(FCEA) levels are significantly elevated and may exhibit higher sensitivity for early-stage
CRC than serum CEA. Enzyme-linked immunosorbent assay (ELISA), a traditional method
for CEA measurement, has limitations, including time-consuming, low reproducibility,
and high optical background. This study aims to develop a sandwich-type electrochemical
immunosensor for CEA detection in both serum and stool.
Methods: Anti-CEA (Ab1) is modified on a low-cost screen-printed carbon electrode (SPCE). For
the capture probe, gold nanoparticles (GNPs) are sequentially modified with streptavidin
(SA), Nile blue A (NBA), and biotinylated anti-CEA (btAb2). The GNPs-SA-NBA-btAb2
conjugates are used to capture target CEA from samples. Then, the capture complex (CEA
bound to GNPs-SA-NBA-btAb2) is applied onto the Ab1-modified electrode. Finally, the
electrochemical signals from the capture probes are measured.
Results: This platform exhibited a calibration curve in the range of 0-100 ng/mL, covering the CEA
cut-off for CRC in both serum (5 ng/mL) and stool (80 ng/mL). This system achieved a limit
of detection (LOD) of 1.17 ng/mL and a limit of quantification (LOQ) of 3.17 ng/mL. The
immunosensor showed the potential to detect CEA in serum and stool samples, comparable
to the FIT test.
Conclusion: This portable, minimally invasive diagnostic immunosensor could be a promising model
for detecting cancer biomarkers in serum or fecal samples for biomarker-based cancer
detection.
Harmony in health: Innovation for Sustainable Medicine
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