In situ PEGylation of Bi nanoparticles prepared via pulsed Nd:YAG laser ablation in low molecular weight PEG: a potential X-ray CT imaging contrast agent

Recent advances and studies have shown that inorganic nanomaterials based on heavy elements represent a new contrast agent which is highly appropriate for X-ray computed tomography (CT) in comparison with commercial Iohexol contrast agents which have several limitations, including short imaging time, rapid renal clearance and toxicity. In this contribution, elemental bismuth (Bi) nanoparticles with polyethylene glycol (PEG) coating are synthesised by pulsed Nd:YAG laser ablation of Bi target in PEGs with 400 and 600 g/mol molecular weight. The effect of PEG molecular weight as surface coating on colloidal stability and size distribution of Bi nanoparticles were investigated. It is found that by in situ surface modification during the ablation in low molecular PEG final particle size as well as average size decreases and colloidal stability increases. Moreover, X-ray attenuation of prepared PEG coated elemental Bi nanoparticles is higher than the commercial Iohexol contrast agent at the same concentration. Finally, the result demonstrates PEGylated Bi nanoparticles can be an appropriate low toxic X-ray contrast agent for the medical application.