Figure 5

(A) Comparison of DNA desorption efficiency at different concentrations of EDTA. Reaction conditions: Initially, 0.5 ml of Sep/DNA samples were prepared using DNA at 640 ng·μl⁻¹ in a sepiolite dispersion (1 mg/ml) in 10 mM Tris-HCl pH = 7.5 and 5 mM MgCl₂. Resuspension in 0.1 ml solution of 10 mM Tris-HCl pH = 7.5, and EDTA at 5, 10 and 50 mM. After 15 min of incubation at room temperature, all samples were centrifuged at 5000 rpm for 5 min, and the supernatant was measured using the UV-vis. (B) Comparison of DNA desorption efficiency for Sep/DNA prepared in the presence of Mg²⁺, Ca²⁺, spermidine (Spd) or spermine (Spm). (C) Characterization with EMSA of desorbed DNA using the “chelation” method. 1) plasmid (5.7 kbp) control; 2) plasmid DNA in the supernatant after synthesis of the bionanocomposite prepared with 5 mM MgCl₂ and before re- suspending the pellet in Tris-HCl pH = 7.5 and EDTA; 3) plasmid DNA desorbed from the bionanocomposite obtained with 5 mM MgCl₂; 4) plasmid DNA desorbed from bionanocomposite obtained with 5 mM CaCl₂.