In this work, an electrochemical sensor was fabricated for determination of an anthracycline, doxorubicin (DOX) as a chemotherapy drug in plasma based on multi-walled carbon nanotubes modified platinum electrode (Pt/MWCNTs). DOX was effectively accumulated on the surface of modified electrode and generated a pair of redox peaks at around 0.522 and 0.647 V (vs. Ag/AgCl) in Britton Robinson (B-R) buffer (pH 4.0, 0.1 M). The electrochemical parameters including pH, type of buffer, accumulation time, amount of modifier and scan rate were optimized. Under the optimized conditions, there was a linear correlation between cathodic peak current and concentration of DOX in the range of 0.05–4.0 μg/mL with the detection limit of 0.002 μg/mL. The number of electron transfers (n) and electron transfer-coe?cient (α) were estimated as 2.0 and 0.25, respectively. The constructed sensor displayed excellent precision, sensitivity, repeatability and selectivity in the determination of DOX in plasma. Moreover, cyclic voltammetry studies of DOX in the presence of DNA showed an intercalation mechanism with binding constant (Kb) of 1.12×105 L/mol.

Acute thromboembolic events have been frequently reported in patients with coronavirus disease 2019 (COVID-19) due to an increase in the coagulation system activity and endothelial dysfunction. This report describes a patient with COVID-19 who initially reported respiratory symptoms and developed acute lower limb ischemia secondary to extensive macrovascular arterial thrombosis, which was treated with thrombectomy. The development of such extensive arterial thrombosis with anticoagulants at therapeutic doses is a new sign of increased viral pathogenicity, and it is necessary to develop and apply updated prophylaxis protocols for thrombosis in these patients.