▎ 摘　　要

Epirubicin is an effective anticancer drug, but naturally causes several side effects. Hence the determination of this drug in biological samples, plays a key role in evaluating its effects and side effects. In this research, a novel label-free DNA-based biosensor was fabricated for the analysis of epirubicin in biological samples. The sensor was fabricated through modifying a pencil graphite electrode with polypyrrole, nitrogen doped reduced graphene (for improving the electrical conductivity) and salmon sperm ds-DNA (PP/NrG/ds-DNA/PGE) and the changes in the electrode signal were used for the determination of epirubicin. The PP/NrG/ds-DNA/PGE showed a high sensitivity for epirubicin in the concentration range of 0.004-55.0 mu M and had a detection limit of 1.0 nM. For further evaluations, the interactions between ds-DNA bases and epirubicin were investigated through a theoretical docking study and the obtained data confirmed the intercalation of epirubicin in the minor grooves of ds-DNA with guanine bases. The PP/NrG/ds-DNA/PGE was used for the analysis of epirubicin in injection and urine samples.