Preparation of Naturally Active Melanin Nano‐Platforms Chelated with Barium Ions as a Potential X‐Ray‐Computed Tomography Contrast Agent

Abstract

Facile preparation of biocompatible nano‐platforms for computed tomography (CT) is demanding. In this work, PEGylated melanin nanoparticles (MNPs) are prepared and reacted with barium ions as CT imaging contrast agent (Ba‐MNPs‐mPEG). It is found that the hydrodynamic size of MNPs is in accordance with size of MNPs measured by electron microscopy (4±1 nm). The zeta potential of MNPs reduces by PEGylation and chelating with Ba2+ ions. Fourier transformed infrared (FTIR) analysis proposed that OH and NH groups of MNPs are possible binding sites for Ba2+ ions. The prepared Ba‐MNPs‐mPEG shows no significant cytotoxicity at concentration up to 100 ppm of barium concentration after 24 h. Finally, our results indicated that the X‐ray attenuation of Ba‐MNPs‐mPEG is similar and slightly higher than Iohexol as the commercially available iodinated contrasting agent at the same concentrations.

A literature review on multimodality molecular imaging nanoprobes for cancer detection

“…Several heavy atoms such as iodine, tungsten, and barium are suitable as contrast media in CT images due to great x-ray attenuation coefficient. For example, Sevda Nedaei et al [23] prepared PEGylated melanin nanoparticles (MNPs) reacted with barium ions as CT contrast media (Ba-MNPs-mPEG). Wallyn and co-workers applied iodinated polymeric nanoparticles with strong X-ray attenuation capacity in the liver and spleen [24].…”