The development of electrochemical DNA biosensor based on poly-L-methionine and bimetallic AuPt nanoparticles coating: Picomolar detection of Imatinib and Erlotinib

We report on the preparation of a new and simple electrochemical DNA biosensor based on DNA/AuPt/p-L-Met coating on a screen-printed carbon electrode (SPE) and its use in the determination of the cancer therapy agents, Imatinib (IMA) and Erlotinib (ERL). Poly-L-methionine (p-L-Met), gold, and platinum nanoparticles (AuPt) were successfully coated by one-step electrodeposition onto the SPE from a solution containing L-Met, HAuCl4, and H2PtCl6. The immobilization of DNA was achieved by drop-casting on the surface of the modified electrode. Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), Field-Emission Scanning Electron Microscopy (FE-SEM), Energy-Dispersive X-ray Spectroscopy (EDX), and Atomic Force Microscopy (AFM) were used to investigate the morphology, the structure, and the electrochemical performance of the sensor. Experimental factors influencing the coating and DNA immobilization processes were optimized. The peak currents originating from guanine (G) and adenine (A) oxidation of ds-DNA were used as signals to quantify IMA and ERL in the concentration range 2.33-80 nM and 0.032-1.0 nM with the LODs of 0.18 nM and 0.009 nM, respectively. The biosensor developed was suitable for determining IMA and ERL in human serum and pharmaceutical samples.

Automated summary

We present a new and facile method for fabricating an electrochemical DNA biosensor using a DNA/AuPt/p-L-Met coating on a screen-printed carbon electrode (SPE) and demonstrate its application in the detection of cancer therapy agents, Imatinib and Erlotinib. Poly-L-methionine (p-L-Met), gold, and platinum nanoparticles (AuPt) were electrodeposited onto the SPE in one step using a solution containing L-Met, HAuCl4, and H2PtCl6. DNA immobilization was achieved through drop-casting on the modified electrode surface. Various characterization techniques were employed to investigate the sensor's morphology, structure, and electrochemical performance. The optimized biosensor exhibited excellent sensitivity and selectivity for quantifying Imatinib and Erlotinib in human serum and pharmaceutical samples, with low LODs of 0.18 nM and 0.009 nM, respectively.