All chemicals and solvents were of reagent grade and purchased from commercial suppliers and used without further purification. The materials including DNA from calf thymus (dsDNA), DNA sodium salt from salmon testes (ssDNA), RNA from torula yeast and BSA, were all procured from Sigma-Aldrich and used as received. Before using in analytical techniques, the purity of DNA was confirmed from the ratio of absorbance intensity at 260/280 nm and was 1.85 ± 0.05 (100.0%). The concentration of DNA was calculated from Beer-Lambert law by using molar extinction coefficient of DNA (13600 M -1 cm -1 ) at 258 nm. The stock solutions of nucleic acids (dsDNA, ssDNA and RNA) and BSA were prepared in PBS (10 mM, pH 7.4) buffer at the concentrations of 1 mg/mL by gentle inversion for overnight at 0 -4 o C without sonication or stirring, particularly to avoid shearing of nucleic acids.