Poly ethylene glycol peg2000

All reagents were of analytical grade and used without further purification. Sodium borohydride (NaBH₄) and 3-Aminopropyltriethoxysilane (APTES) were purchased from Shanghai Aladdin biochemical technology Co., Ltd. (Shanghai, China) Chloroauric acid hydrate (HAuCl₄·3H₂O) and sodium citrate were purchased from Sigma–Aldrich (Shanghai, China). Fluorescein isothiocyanate (isomeride I) (FITC > 95.0%) was purchased from TCI (Shanghai, China) chemical industry Co., Ltd. Copper, aluminum, nickel, cobalt, barium, cadmium, manganese, iron, zinc, strontium, bismuth, chromium were purchased from Guobiao (Beijing, China) Testing & Certification Co., Ltd. The nitrate, acetate, or chloride salts of other metal ions were purchased from Sinopharm Chemical Reagent Co, Ltd.(Shanghai, China). Ethylene glycol, ethanolamine, ethanol and Poly (Ethylene glycol) (PEG2000) were purchased from Sinopharm Chemical Reagent Co, Ltd. (Shanghai, China).

Polyethylene glycol (PEG, 2000), potassium chloride (KCl), hydrochloric acid (HCl), acetone (CH₃COCH₃) and phosphate buffered saline (PBS, pH 7.4) were purchased from Sinopharm Chemical Reagent Company, Ltd. (Shanghai, China). All chemicals used in the experiments were of reagent grade quality or better and were used without further purification. Aqueous solutions were prepared from de-ionized water. Quartz capillaries (o.d. = 1.0 mm, i.d. = 0.3mm) were purchased from Sutter Instrument Company (Novato, CA, USA).