Figure 5.

(a) The change of Ca²⁺ amount after Ca-P mineral coatings grown on pre-hydrolyzed PLG films in 2 ×, 3.5 ×, or 5 × SBF solutions were immersed for 24 h in 0.05 M Pipes-buffered solutions containing 0 ×, 0.3 ×, 0.6 ×, or 1 × of physiologic [Ca²⁺] and [PO₄³⁻] at pH 7.4. The change of Ca²⁺ amount calculated by subtracting initial Ca²⁺ amount in different solutions from Ca²⁺ amount after 24 h incubation, (b) Cumulative change of Ca²⁺ and (c) Cumulative plasmid DNA amounts from Ca-P mineral coatings grown on pre-hydrolyzed PLG films in 2 × SBF solution after plasmid DNA binding. Ca-P mineral coatings with bound plasmid DNA were immersed for 3 weeks in 0.05 M Pipes-buffered solutions containing 0 ×, 0.3 ×, 0.6 ×, or 1 × of physiologic [Ca²⁺] and [PO₄³⁻] at pH 7.4. The amount of released Ca²⁺ and plasmid DNA were increased with decreasing [Ca²⁺] and [PO₄³⁻] in the solutions.