Guanine-Based DNA Biosensor Amplified with Pt/SWCNTs Nanocomposite as Analytical Tool for Nanomolar Determination of Daunorubicin as an Anticancer Drug: A Docking/Experimental Investigation

Daunorubicin is a famous anthracycline anticancer chemotherapy drug with many side effects that is very important to measure in biological samples. A daunorubicin electrochemical biosensor was fabricated in this study using ds-DNA as the biorecognition element and glassy carbon electrode (GCE) amplified by Pt/SWCNTs as a sensor. The synthetization of Pt/SWCNTs was done by the polyol method, and their characterization was accomplished via XRD, EDS, and TEM methods. The results showed a diameter of about 5.0 nm for the Pt nanoparticle decorated at the surface of SWCNTs. The morphological and conductivity properties of Pt/SWCNTs/GCE were investigated by EIS and AFM methods, and the results confirmed that Pt/SWCNTs/GCE had a high surface area and high conductivity. ds-DNA/Pt/SWCNTs/GCE showed an oxidation signal relative to that of the guanine base at the potential of 847 mV and a positive shift after interaction with the daunorubicin anticancer drug. This point confirms the intercalation reaction between the guanine base in the ds-DNA structure and the drug that could be used as an analytical factor for the determination of daunorubicin. Furthermore, molecular docking study is used to predict the interaction site of daunorubicin with DNA. It is found that daunorubicin interacts with guanine bases of DNA via an intercalative mode. Kinetic investigation showed an association equilibrium constant (K-a) of about 5.044 X 10(-3) M-1 between ds-DNA and daunorubicin. The differential pulse voltammetric results showed a linear dynamic range of 4.0 nM to 250.0 mu M with a detection limit of 1.0 nM for determination of daunorubicin on the surface of ds-DNA/Pt/SWCNTs/GCE. Finally, ds-DNA/Pt/SWCNTs/GCE was successfully used for the determination of daunorubicin in injection samples with a recovery range of 98.27-10313%.