Amberlite ir120 hydrogen form

In a colloidal solution, 40 nm AuNPs were coated with silica by the Stöber method [14 (link)]. Briefly, 50 mL of AuNPs were reacted with 0.25 mL of 1 mM APTMS for 15 min at 25 °C under vigorous magnetic stirring. The solution of active silica at low pH was prepared from a 0.54 wt % sodium silicate solution at pH 10 using a cation exchange resin (Amberlite^® IR120 hydrogen form, Sigma–Aldrich). Then, 2 mL of active silica was added to 50 mL of the solution (1:4 water/ethanol) containing the silica shell particles and maintained under vigorous magnetic stirring for 24 h. Then, 0.15 mL of TEOS and 1 mL of ammonia were added, and the solution was maintained for another 12 h under mild magnetic stirring. To modify the surface of Au@SiO₂ with carboxyl groups (COOH), 50 mL of particles with silica were reacted with 0.25 mL of 1 mM APTMS for 15 min. Then, 500 mg of succinic anhydride were dissolved in 1 mL of DMSO for 24 h at 25 °C under magnetic stirring. Finally, the nanoparticles were subsequently washed 3 times with Milli-Q water to remove excess reagents and were resuspended in nuclease-free water, followed by the UV-Vis spectroscopy, DLS, and STEM characterizations.

Gluconolactone, d-maltose monohydrate, lactobionic acid, cysteamine hydrochloride, and 2,2-dimethoxy-2-phenylacetophenone (DMPA) were purchased from Sigma Aldrich. Pentamethyldisiloxane (PMDS), bis(trimethylsiloxy)-methylsilane (BisH), vinyltrimethoxysilane, vinyltris(trimethylsiloxy)methylsilane (V1), and MCS-V212 (V4) were purchased from Gelest. Iodine was purchased from Anachemia, and potassium hydroxide and sodium bicarbonate were obtained from Caledon Laboratories. All compounds were used as received. Solvents methanol, ethanol, 2-propanol, hexane, dichloromethane, and toluene were also purchased from Caledon and dried through an activated alumina column as needed. Anhydrous methanol, deuterated chloroform (CDCl₃), and deuterated DMSO-d₆ were purchased from Sigma Aldrich and used as received. Neutral alumina was purchased from Fisher Chemical. A Celite S filter aid and Amberlite IR120, hydrogen form, the latter rinsed with distilled water before use, were purchased from Sigma Aldrich. Silsurf J1015-O and Silsurf A008-up were a gift from Siltech Corporation. Silwet L-7657 was purchased from Momentive. n-Wet and o-Wet were provided by EnRoute Interfaces, Inc.
Compounds V2,V3, and V1–V4 → CV1–CV4 have previously been reported [1 (link)]. We include, below, the preparation of V2 and conversion to CV2 to illustrate the simplicity of the process.