“…Theorell and Stenhagen universal buffer was prepared by dissolving phosphoric acid (2.25 mL, 85 % w/w), boric acid (3.54 g), monohydrated citric acid (7.00 g), and NaOH (343 mL, 1 m) solution diluted in distilled water until 1 L. The other reagents were obtained from Sigma–Aldrich (Madrid, Spain). 3[G4]‐OSO 3 Na, a GATG dendrimer of fourth generation with 162 terminal sodium sulfate groups ( M W : 61 672 g mol −1 ) was obtained from 3[G3]‐N 3 by azide–alkyne cycloaddition. A solution of 3[G3]‐N 3 (47 mg, 1.97 μmol) and ammonium 4,11‐dioxo‐5,10‐dioxa‐3,12‐diazatetradec‐7‐yne‐1,14‐diyl bis(sulfate) (145 mg, 0.319 mmol) in t BuOH/H 2 O 1:1 (160 μL) was stirred at 120 °C for 8 h and then was purified by ultrafiltration (4×30 mL, 0.1 m NaOH and 2×30 mL H 2 O, Amicon YM3) and lyophilized to afford 3[G4]‐OSO 3 Na as a white foam (108 mg, 91 %).…”