A thin film of poly-arginine fabricated on glassy carbon electrode by one step electrodeposition method is applied for detection of doxorubicin hydrochloride in whole blood, cell lysate, and untreated-plasma samples. Cyclic voltammetry results indicated that the doxorubicin is oxidized via two electrons and two protons at physiological pH (pH=7.4) using poly-arginine thin film modified glassy carbon. More importantly, electrostatic repulsion takes place between the prepared polymer film-modified electrode and selected drug resulting in the signal amplification on oxidation of doxorubicin and lowering its over potential and thereby selective detection of doxorubicin in real samples. The apparent electron transfer rate constant and transfer coefficient were determined by cyclic voltammetry and were approximately 10.1s-1 and 0.82, respectively. Also, using differential-pulse voltammetric technique for sensitive detection of doxorubicin in whole blood and plasma samples, the lower limit of quantification was 69nM and 103nM, respectively. Also, application of this amino acid based biocompatible polymeric electrode was tested to the determination of doxorubicin in unprocessed whole blood and the results show that this sensor could be applied in online and real time monitoring of this anti-cancer drug in real samples which is important for clinical research.
Keywords: Biological fluids; Cell lysate; Doxorubicin; Electrochemistry; Poly-amino acid; Whole blood.
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