Sodium pyrophosphate

Chloroauric acid (HAuCl4·4H2O), chloroplatinic acid hexahydrate (H2PtCl6·6H2O), silver nitrate, copper sulfate pentahydrate (CuSO4·5H2O), NaOH, KNO3, KCl, hemin, adenosine triphosphoric acid (ATP) and sodium pyrophosphate were obtained from Sinopharm Chemical Reagent Co. (Shanghai, China).
Guanine (G)-rich 5′-GGGTAGGGCGGGTTGGG-3′ (G-rich ODN) and Guanosine (G)-free 5′-AAATAAAACAAATTAAA-3′ (G-free ODN, for control experiment) were obtained from Sangon Biotechnology Co. Ltd. (Shanghai, China) and dissolved or diluted in sterile deionized water. The S1 nuclease was achieved from TaKaRa Biotechnology (Dalian, China). The S1 nuclease buffer (2 mM NaAc, 15 mM NaCl, and 0.1 mM ZnSO4, pH 4.5) was used for S1 dilution and enzymatic digestion reaction. All other chemicals were of analytical grade and used without further treatment. Deionized water was prepared using a Millipore Milli-Q water purification system (18.2 MO). Fresh hen eggs were bought from local market without special selection and the egg white was taken from them by drawing.
Escherichia coli (E. coli) cell medium were obtained friendly.
The fluorescence spectra were recorded on a fluorescence spectrophotometer (Hitachi, F-4600). Zeta potential measurements were carried out on a Malvern Zetasizer Nano ZS. The circular dichroism (CD) spectra were recorded on a Jasco 815 spectropolarimeter.