Studies on Electrochemical Behavior of Bleomycin and Its Interaction with DNA at a Co/GC Ion Implantation Modified Electrode

Screen-Printed Electrodes-A Promising Tool for Antineoplastic Drug Detection (Cisplatin and Bleomycin) in Biological Samples

Cancer remains one of the leading causes for death worldwide. Palliative chemotherapy is vital for certain cancer patients, highlighting the critical need for treatment monitoring tools to prevent drug accumulation and mitigate the risk of high toxicity. Therefore, our aim was to evaluate the potential of screen-printed electrodes for the development of sensitive and accurate biosensors for the detection/quantification of antineoplastic drugs. To this purpose, we developed a cisplatin sensor. By functionalizing the gold electrode with human serum albumin and by collecting the electrochemical signal obtained in a H2O2 solution, through voltammetry measurements, we were able to correlate the current measured at 430 mV with the concentration of cisplatin present in human serum samples, with a correlation coefficient of R2 = 0.99. Also, a bleomycin biosensor was developed and proven functional, but further optimization steps were employed in order to improve the accuracy. The developed biosensors have a detection range of 0.0006-43.2 mg/mL for cisplatin and 0.23-7.56 μg/mL for bleomycin in the serum samples. Our preliminary results show that these biosensors can facilitate the real-time monitoring of cisplatin and bleomycin serum levels, allowing healthcare professionals to tailor treatment strategies based on individual patient responses.

Investigation of the interaction between quercetin and human serum albumin by multiple spectra, electrochemical impedance spectra and molecular modeling

Quercetin (Qu), a flavonoid compound, exists widely in the human diet and exhibits a variety of pharmacological activities. This work is aimed at studying the effect of Qu on the bioactive protein, human serum albumin (HSA) under simulated biophysical conditions. Multiple spectroscopic methods (including fluorescence and circular dichroism), electrochemical impedance spectra (EIS) and molecular modeling were employed to investigate the interaction between Qu and HSA. The fluorescence quenching and EIS experimental results showed that the fluorescence quenching of HSA was caused by formation of a Qu-HSA complex in the ground state, which belonged to the static quenching mechanism. Based on the calculated thermodynamic parameters, it concluded that the interaction was a spontaneous process and hydrogen bonds combined with van der Waal's forces played a major role in stabilizing the Qu-HSA complex. Molecular modeling results demonstrated that several amino acids participated in the binding process and the formed Qu-HSA complex was stabilized by H-bonding network at site I in sub-domain IIA, which was further confirmed by the site marker competitive experiments. The evidence from circular dichroism (CD) indicated that the secondary structure and microenvironment of HSA were changed. Alterations in the conformation of HSA were observed with a reduction in the amount of α helix from 59.9% (free HSA) to 56% (Qu-HSA complex), indicating a slight unfolding of the protein polypeptides.