The sequence of the peptide was expressed as EYNFDFKFNYH. The peptides were synthesized by the general solid-phase peptide synthesis (Fmoc-SPPS) methodology on Wang resin. Then, the peptide EH was obtained and purified by high performance liquid chromatography (HPLC). Next, 50 µL of Ag2S solution (2 mg mL -1 ) was mixed with 950 µL of EH solution (2 mg mL -1 ) and uniformly dispersed by ultrasonic. Then, the pH value of the above mixed solution was adjusted to 7.4 with 1 mM NaOH solution.