Prot-IONPs were synthesized through a coprecipitation approach
based on a previously reported method.52 (link) Briefly, 1 mL of the protein scaffold at 45 μM was mixed with
a 2:1 mixture of FeCl2·4H2O and FeCl3·6H2O (6 eq. respect to Glu metal-binding
residues) under a nitrogen atmosphere. Then, the reaction mixture
was incubated for 30 min at room temperature and a 0.1 mM NaOH solution
was added until a pH value equal to 10 was reached. Then the reaction
was sonicated for 10 min at 65 °C, and a solution of sodium ascorbate
(10 equiv with respect to iron ions) was added to the reaction mixture,
which was again sonicated for 10 min at 65 °C. Finally, Prot-IONPs
were purified by gel filtration using a PD-10 column containing Sephadex
G-25 resin (Cytiva).
based on a previously reported method.52 (link) Briefly, 1 mL of the protein scaffold at 45 μM was mixed with
a 2:1 mixture of FeCl2·4H2O and FeCl3·6H2O (6 eq. respect to Glu metal-binding
residues) under a nitrogen atmosphere. Then, the reaction mixture
was incubated for 30 min at room temperature and a 0.1 mM NaOH solution
was added until a pH value equal to 10 was reached. Then the reaction
was sonicated for 10 min at 65 °C, and a solution of sodium ascorbate
(10 equiv with respect to iron ions) was added to the reaction mixture,
which was again sonicated for 10 min at 65 °C. Finally, Prot-IONPs
were purified by gel filtration using a PD-10 column containing Sephadex
G-25 resin (Cytiva).
