Contrast enhancement of iohexol-cisplatin-gelatin complex under computed tomography imaging

X-ray computed tomography (CT) is one of the most powerful non-invasive diagnostic techniques nowadays. The iodinated molecules used as CT contrast agents in the clinic have short circulation times in the body, which significantly restrict its applications. Furthermore, some patients are hypersensitive to iodine. So, researchers have made tremendous efforts to improve the property of iodine. Besides, cis-diammineplatinum (II) dichloride (cisplatin), a major chemo agent for cancer treatment, possess higher X-ray attenuation coefficient being a CT contrast agent. The incorporation of cisplatin with an iodinated agent could facilitate the quality of CT images and damage cancer cells simultaneously. To reduce toxicity of a contrast agent, polymer matrix, gelatin, was incorporated for avoiding contact with nontarget cells. In this study, we combined the iodine contrast agent, 1,3-N-bis (2,3-dihydroxypropyl)-5-[N-(2,3-dihydroxypropyl)acetamido]-2,4,6-triiodobenzene-1,3-dicarboxamide (iohexol), with cisplatin, and then examined them in a micro CT with different X-ray tube voltages (50 kV, 80 kV, 100 kV) to find optimal scanning conditions for imaging. As expected, iohexol combined with cisplatin enhanced X-ray attenuation and image contrast. The optimal CT image could be acquired at iohexol and cisplatin concentrations of 50 mg/ml and 3 mg/ml, respectively, under 80 kV irradiation. Finally, the iohexol-cisplatin-gelatin solution was then fabricated into nanoparticles of sizes about 240 nm, which may suitable for in vivo delivery.