Low-molecular DNA from salmon testes (DNA1, <5% protein, A260/280 = 1.4), from fish sperm (DNA2, mol. weight 40–1000 kDa), and from chicken erythrocytes (DNA3, “Reanal”, Budapest, Hungary, average mol. mass 1.2 MDa), doxorubicin hydrochloride (98–102%) (Figure 1a), idarubicin hydrochloride (>98%), daunorubicin hydrochloride (>90%), valrubicin (<100%), cyclophosphamide (EP reference standard), prednisone (dehydrocortisone, >98%), dacarbazine (EP reference standard), potassium hexacyanoferrate (III) (99%), potassium hexacyanoferrate (II) trihydrate (98.5–102%), and HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) were purchased from Sigma-Aldrich, Dortmund, Germany. All solutions were prepared with Millipore Q® water (Simplicity® water purification system, Merck-Millipore, Mosheim, France). Doxorubicin-TEVA® and Doxorubicin-LANS® (lyophilizates for intravascular injection solutions) were purchased at a local pharmacy market.
The PhTz (chemical structure in Figure 1b was synthesized as described elsewhere [57 (link)]. For electropolymerization, it was dissolved in acetone and then mixed with 0.4 M H2SO4 in 1:1 (v/v) ratio. In electropolymerization, the working concentration of PhTz (72 μM) corresponded to its maximal solubility. DNA was dissolved in deionized water.
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