2.1. Materials

Mercapto-ethylamine (MEA) was purchased from Xiya Reagent (Linshu, Shandong, China). Poly(ethylene glycol) diglycidyl ether (PEGDE, M_n = 500 g·mol⁻¹) was obtained from Sigma-Aldrich Co. (Shanghai, China). Silver nitrate (AgNO₃), alcohol and n-hexane were purchased from Tian Jin Chemical Reagent (Tianjin, China). 3-(4,5-dimethylthiazol-2-yl)-2,5-ziphenyl tetrazolium bromide (MTT) was purchased from Amresco Inc. (Solon, OH, USA). Dulbecco’s modified eagle medium (DMEM) and fetal bovine serum (FBS) were obtained from Gibco BRL Co. (Gaithersburg, MD, USA). The phosphate buffer saline (PBS) was made in laboratory according to the literature [31]. Briefly, potassium chloride (4 g), potassium phosphate monobasic (4 g), sodium chloride (160 g), and sodium phosphate dibasic heptahydrate (43.2 g) were dissolved in 1 L deionized (DI) water. Staphylococcus aureus (ATCC 6358P), Escherichia coli (CGMCC 1.90) and Bacillus subtilis (CGMCC 1.1849) were used for the bacterial studies. All microorganisms were provided by China General Microbiological Culture Collection Center (CGMCC), Chinese Academy of Sciences (CAS), Beijing, China. The bacterial strains were grown in Luria-Bertani agar plates from Hopebiol (Qingdao, Shandong, China) at 37 °C.