Tham khảo tài liệu 'biosensors for health environment and biosecurity part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 342 Biosensors for Health Environment and Biosecurity attributed as due to 8-oxo-Guanine 8-oxo-G oxidation and that at may be due to the oxidation of purine bases of DNA. A clear separation of the peak due to 8-oxo-G and epirubicin can be explained on the basis of non-uniform coverage of the GCFE surface by DNA and adsorption of epirubicin at these uncovered surfaces. The results are in good agreement with those observed using thick layer DNA modified GCFE . This shift of 8-oxo-G peak to less positive potential informs about the DNA-epirubicin interaction damage to DNA . Fig. 8. Differential Pulse Voltammogram in acetate buffer at pH obtained with a thin layer ds-DNA modified GCFE after being immersed in 20jrg ml epirubicin solution during 180 s after applying a potential V during 60 s. Epirubicin-DNA interaction at thick layer ds-DNA modified GCFE Epirubicin produced a well-defined voltammetric oxidation peak with Ep value . The height of the epirubicin oxidation peak with respect to the time of immersion of the thick layer ds-DNA modified GCFE in epirubicin solution was investigated. The results showed a linear relationship between the peak height and time of immersion of the electrode in epirubicin solution to 60 min and then it attained a constant value. Thus indicating the preconcentration of epirubicin at the thick layer ds-DNA modified electrode surface. It is important to note that reproducible peak currents were observed for the similar time of immersion of the thick layer ds-DNA modified GCFE in epirubicin solution for the first scan only. However if the differential pulse voltammogram is recorded using the same modified electrode an abrupt decrease in the peak current was observed. This suggests a fast consumption of the neoplasic drug at the modified electrode surface. However on performing the above voltammetric experiments separately using bare GCFE and thick layer ds-DNA modified GCFE as working electrode .
