Herin, a flower-like porous MnO₂-modified pencil graphite electrode (MnO₂-PGE) is developed for the electrochemical determination of the anticancer drug daunorubicin and its interaction with dsDNA. The developed electrochemical nanobiosensor has some advantages, such as easy-to-handle, cost-effective, portable, less time-consuming assay and disposable.

Despite the indisputable efficacy of chemotherapy in the treatment of cancer, the adjustment of chemotherapy drug dosage remains a concern. Therefore, herein, a flower-like nanomaterial is developed as an electrochemical nanobiosensor for cancer drug determination, considering the advantages of providing a lower limit of detection (LOD) by increasing the electrode surface area. A flower-like porous manganese oxide (MnO₂) is synthesized and modified onto the surface of a pencil graphite electrode (PGE). It is used to investigate the interaction between dsDNA and daunorubicin (DNR), as an anticancer drug, using the voltammetric technique. As a result of the measurements made with developed MnO₂-PGE using DPV, the LODs of dsDNA and DNR are calculated as 0.62 μg mL⁻¹ and 54 nM, respectively. The dsDNA–DNR interaction investigation revealed that, in just three minutes, the maximum interaction is achieved and a 26.9% reduction in the dsDNA guanine signal is noted. On the other hand, there is an 81.2% decrease in the DNR oxidation signal. Kinetic investigation shows a binding constant (K) of 1.81 × 10⁶ M⁻¹ between dsDNA and DNR. The LOD of DNR using the dsDNA/MnO₂-PGE surface is calculated as 0.06 μM in a linear dynamic range of 0.1–0.5 μM.