The effect of various amounts of antibody bound to the surface
of gold nanoparticles was studied in the concentration of the antibody
from 0 to 1 mg mL−1 by evaluating the absorbance at 520 nm
with respect to the antibody concentrations used. As the concentration
of antibody increased, the absorbance also increased up to
a maximum at 0.5 mg mL−1 of antibody and then the absorbance
decreased (data not shown). Therefore, the minimal concentration
of antibody necessary to stabilized gold nanoparticles was approximately
at 0.5 mg mL−1.