Exploring the impact of pH on the properties of citric acid-coated iron oxide nanoparticles as high-performance T2 contrast agent for MRI applications

Iron oxide nanoparticles (IONPs) were synthesized using an aqueous co-precipitation method at various pH levels ranging from 8 to 12. The impact of solution pH on IONPs' properties was analyzed by studying their size, shape, and surface charge. Both the crystalline structure and size of IONPs were significantly affected by pH levels, as revealed by X-ray diffraction analysis. Across all pH values, magnetite was found to be the predominant phase. Interestingly, the smallest nanoparticle size was observed at pH 10. The IONPs synthesized at the optimal pH were then coated with citric acid to be used as contrast agents in Magnetic Resonance Imaging (MRI). The citric acid coating was applied to the IONPs to increase their biocompatibility and optimize their dispersity. The coated samples were further characterized using Zetasizer, Fourier-Transform Infrared Spectroscopy (FTIR), and Vibrating Sample Magnetometry (VSM). The results indicated high stability and appropriate magnetization, with a relaxivity ratio (r2/r1) of 73.75, making citric acid-coated IONPs a promising candidate for use as T2 MRI contrast agents. FTIR, Zetasizer, and VSM measurements indicated that the citric acid coating had a positive effect on the biocompatibility, stability, and magnetization of the IONPs. IONPs are excellent T2 MRI contrast agents because of their enhanced physiochemical properties, and their high relaxivity ratio confirms their effectiveness. The findings of this study emphasize the crucial role that pH plays in determining the properties of IONPs and highlight the potential use of citric acid-coated IONPs in medical imaging applications such as MRI.