Fig. 2. Stability and loading/release study of iron(iii) chelated polymeric NPs. (A) Stability of NPs over 4 weeks period when stored at 4 °C showing the change of size and polydispersity index, (B) serum stability test to measure dynamic aggregation of PLGA NPs and Fe–PLGA NPs using 90% fetal bovine serum environment to find the rapid increase in optical density of 560 nm due to NPs aggregation by forming protein corona, (C) iron loading efficiency with the different initial feeding concentration of Fe³⁺ per mg PLGA, and (D) a comparative Fe and Gd release study from Fe–PLGA NPs and Magnevist® in simulated body fluid (SBF), respectively. Data represents mean ± S.D, n = 3.