2 aminoethanethiol

Lysozyme, cytochrome C, insulin, vascular endothelial growth factor (VEGF), bovine serum albumin (BSA) and gold(iii) chloride (HAuCl₄) solution were purchased from Sigma-Aldrich (St. Louis, USA). 2-Aminoethanethiol or cysteamine (C₂H₇NS) was obtained from Tokyo Chemical Industry Co., Ltd (Kyoto, Japan). Sodium borohydride (NaBH₄) was purchased from Nacalai Tesque Inc. (Kyoto, Japan). The oligonucleotide was provided by Integrated DNA Technologies (IDT). 1× phosphate buffered saline (PBS) at pH 7.4 was used. All reagents and chemicals were of analytical grade and used without further purification. Deionised water (DI H₂O) with measured conductivity of 18.2 MΩ cm was used throughout all experiments. Unless otherwise stated, all experiments were conducted at room temperature (20 °C).

Dulbecco’s Modified Eagle Medium and fetal bovine serum (FBS) were purchased from Gibco (Thermo Fisher Scientific, Waltham, MA, USA). Cobalt Hexahydrate, hydrogen tetrachloroaurate (III) trihydrate (HAuCl₄·3H₂O) and ethylene chloride were purchased from Alfa Aesar (Heverhill, MA, USA). Cethyltrimethylammonium bromide (CTAB) and 1-Butanol were purchased from Sigma-Aldrich (St. Louis, MO, USA). Isooctane was purchased from Tedia (Fairfield, OH, USA). Methotrexate (MTX), sodium borohydride were purchased from Acros organics (Fair Lawn, NJ, USA), silver nitrate (AgNO₃), ascorbic acid and citric acid were purchased from Honeywell Riedel-de Haen (Seelze, Germany). 2-Aminoethanethiol was purchased from Tokyo Chemical Industry (TCI, Tokyo, Japan). All other chemicals of analytical grade were purchased from Sigma (St. Louis, MO, USA).