Zhumabekova, Zhazira2022-08-112022-08-112022-06Zhazira Zhumabekova. 2022. Application of novel SSDNA aptamers for the detection of carcinoembryonic antigen using surface Plasmon resonance. School of Sciences and Humanitieshttp://nur.nu.edu.kz/handle/123456789/6572Carcinoembryonic 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.enAttribution-NonCommercial-ShareAlike 3.0 United StatesType of access: Embargocarcinoembryonic antigenaptamerssurface plasmon resonancegold nanoparticlesMaster's thesis