Development of an aptamer-functionalized gold electrode-based electrochemical biosensor for the detection of cytochrome-c as an apoptosis biomarker

Date

2026-8-31

Author

Karayalçın, Gizem

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This thesis focused on the detection of Cytochrome-c (Cyt-c), an important apoptosis biomarker, through an electrochemical aptamer-based biosensor system employing aptamer functionalized gold electrodes. Since apoptosis plays a critical role in the evaluation of drug-induced cell death and therapeutic response, monitoring Cyt-c released from cells holds great importance. Conventional apoptosis detection methods generally require labeling, cell lysis, complex sample preparation, or long analysis times; therefore, an electrochemical biosensor platform was developed to provide a rapid, sensitive, and selective alternative. An electrochemical approach was adapted since aptamer based biosensing is wellestablished for the specific recognition of target biomolecules. In this system, thiolmodified Cyt-c specific aptamers were immobilized onto gold electrode surfaces, and 6-mercapto-1-hexanol (MCH) was used to minimize nonspecific interactions. The sensor surface was characterized using electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV). The developed sensor yielded an estimated EIS based limit of detection of approximately 22 nM. In addition, the apoptotic response of HT-29 cells and Cyt-c release were tested using doxorubicin. The developed sensor proved to be promising for monitoring drug-induced apoptosis and future lab-on-a-chip applications.

Subject Keywords

Cytochrome-c, Apoptosis, Electrochemical Biosensor, Aptamer, Doxorubicin

URI

https://hdl.handle.net/11511/121029

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Graduate School of Natural and Applied Sciences, Thesis