APPLICATION OF NOVEL SSDNA APTAMERS FOR THE DETECTION OF CARCINOEMBRYONIC ANTIGEN USING SURFACE PLASMON RESONANCE
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Date
2022-06
Authors
Zhumabekova, Zhazira
Journal Title
Journal ISSN
Volume Title
Publisher
Nazarbayev University School of Sciences and Humanities
Abstract
Carcinoembryonic antigen (CEA) is an important Food and Drug Administration
approved biomarker in cancer detection, especially in colorectal cancer. This research is
based on the development of a real-time rapid detection tool for the detection of CEA
employing novel aptamer sequences through Surface Plasmon Resonance (SPR).
Aptamers are small single-stranded nucleotides capable of binding to target molecules
with high affinity and specificity. SPR is an optical sensor that allows to detect the
refractive index on the gold surface of a sensor chip. In this study, a streptavidin (SA)
coated sensor chip was functionalized with the biotinylated CEA aptamer sequence (6) to
further detect the target protein using the direct SPR aptasensor. The detection limit for
direct SPR was determined to be 150 ng/ml. To further enhance the response unit (RU)
of the SPR aptasensor, AuNPs – aptamer (8) conjugates were employed as a competitive
reagent in the indirect competitive inhibition assay (ICIA) for the detection of CEA. For
this purpose, AuNPs were successfully functionalized with a thiol-modified long-linker
(HS - (CH2)6 - OP(O)2O - (CH2CH2O)6 - 5 - TTTTT) aptamer (8) against the CEA, which
were characterized by UV-vis spectrophotometry, measurement of the electrostatic
potential, and transmission electron microscopy. In the ICIA, the sensor chip SA surface
was first immobilized with the biotinylated aptamer (6) sequence and worked as a sensing
surface. When the AuNPs – aptamer (8) conjugates were mixed with the target CEA, it
could potentially induce the change in the aptamer structure from ssDNA structure to
tertiary structure. This led to the SPR RU increase up to 500 RU at 350 ng/mL
concentration of CEA. Here, we showed that novel aptamer sequences against CEA can
be employed in the development of SPR aptasensor that could be either in the direct or
ICIA based mode that is real-time and label-free.
Description
Keywords
Type of access: Embargo, carcinoembryonic antigen, aptamers, surface plasmon resonance, gold nanoparticles
Citation
Zhazira Zhumabekova. 2022. Application of novel SSDNA aptamers for the detection of carcinoembryonic antigen using surface Plasmon resonance. School of Sciences and Humanities