Figure 7
(A) Sepiolite-mediated stable gene transfer into mammalian cells. An image of colonies of transfected V79 cells with Sep/DNA prepared with 10 mM MgCl2 (left) and 10 mM CaCl2 (right). (B) An image of colonies of transfected V79 cells with Sep/DNA prepared with 10 mM CaCl2 (1, 2), 0.2 mM spermidine (3, 4) and 0.2 mM spermine (5, 6). First day: 2·104 cells were plated in each well. Second day: 3 ml of new medium containing Sep/DNA bionanocomposite with 40 μg of sepiolite and 1 μg of bound DNA in the presence of polyvalent cation was added. After two days, the cells were washed with PBS and new medium was added with antibiotic G418 at 600 ng·μl−1 to start the selection. After 10 days, the cell colonies were stained with Giemsa (25% in ethanol). (C) A comparison of the number of colonies of transfected U2OS human cells with Sep/DNA (with vortexed sep in 1, 2 and 3), and sSep/DNA (with sonicated sep in 4, 5 and 6). First day: 104 cells were plated in each well. Second day: 9 ml of new medium was added (3 ml in each well) in the presence of Sep/DNA (1–3) and sSep/DNA (4–6) bionanocomposites prepared from 80 μg of sepiolite and 3 μg of bound DNA in the presence of CaCl2. After two days, the cells were washed with PBS and new medium was added with antibiotic G418 at 800 ng·μl−1 to start the selection. After 10 days, the cell colonies were stained with Giemsa.
