As shown in Fig. 1B, the
chitosan nanoparticles had a zeta potential of þ49.50 mV (Fig. 1B).
For a physically stable nanosuspension solely stabilized by electrostatic
repulsion, a zeta potential of ±30 mV is required as a
minimum (Muller et al., 2001). All these data suggested that chitosan
nanoparticles prepared here were stable.