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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 53949 (06)
- University: Sharif University of Technology
- Department: Chemical and Petroleum Engineering
- Advisor(s): Abdekhodaie, Mohammad Jafar
- Abstract:
- Today, despite the notable progress in diagnostics and therapeutics, cancer remains the second cause of death worldwide. This rather high mortality rate is often attributed to cancers diagnosed at late stages, including prostate cancer. Among the techniques approved for prostate cancer diagnosis, total or free prostate-specific antigen screening using blood serum samples is the sole method able to detect prostate cancer at an early stage. This test has led to a significant decrease in prostate cancer-related deaths. Nonetheless, it possesses several drawbacks, such as the complex, costly, and time-consuming conventional methods utilized in clinical laboratories to assess the concentration of total or free prostate-specific antigen and the fact that it is not entirely specific to prostate cancer. In this study, a novel electrochemical biosensor was proposed as a more user-friendly, cost-effective, and rapid means of prostate-specific antigen screening. Moreover, in addition to serum samples, urine specimens were also exploited as a reliable source of total prostate-specific antigen to increase the assay’s specificity toward prostate cancer. In order to enhance the electrical conductivity of the biosensor, the pencil graphite working electrode’s surface was chemically pretreated with nitric acid and subsequently modified with amino-functionalized graphene oxide nanoparticles. Following antibody immobilization on the modified working electrode surface and antibody-antigen interactions generated by inserting the working electrode in a sample containing the desired analyte, label-free detection was carried out, and cyclic voltammetry was performed to determine the antigen concentration. The biosensor exhibited a linear range and detection limit of 0.01-1000 ng/ml and 0.68 pg/ml, as well as 0.1-1000 ng/ml and 7.21 pg/ml for total and free prostate-specific antigens, respectively. These values demonstrate the high accuracy and sensitivity of the designed biosensor. Also, the results obtained from the selectivity, reproducibility (relative standard deviation of less than 2 %), and stability (less than 3 % change in current output after one month) analyses, as well as the validation tests using commercial enzyme-linked immunosorbent assay kits (roughly 95 % agreement between the concentrations gained from the fabricated biosensing assays and those obtained from the kits), showcase the potential application of this electrochemical biosensor in clinical settings
- Keywords:
- Early Detection ; Cyclic Voltammetry ; Graphene Oxide ; Electrochemical Biosensors ; Prostate Cancer ; Prostate Specific Antigen ; Pencil Graphite Electrode
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