Radiopaque Silk Sericin Nanoparticles for Computed Tomography Imaging of Solid Tumors.

Computed tomography (CT) is a non-invasive technology which is commonly used for cancer diagnosis owing to its high efficiency and widespread availability. But the inability to differentiate soft tissues with similar densities is the major limitation of CT. In the present study, silk sericin nanoparticles (SNP) prepared using the ethanol desolvation method were functionalized using diatrizoic acid (DTA). The prepared DTA-functionalized SNP (D-SNP) were spherical in shape with a mean hydrodynamic diameter of 52.6 nm. D-SNP were non-hemolytic and non-cytotoxic when treated with human erythrocytes and fibroblasts. D-SNP showed excellent in vitro CT imaging performance, with enhanced CT signals with the increase in the concentration of D-SNP, resulting in brighter CT images. In vivo experiments carried out using B16-F10 melanoma-bearing mice showed enhanced tumor visibility after 30 min of administration of D-SNP, thereby elucidating their efficient role as a CT contrast agent. The biosafety profile of D-SNP was studied by injecting the nanoparticles in BALB/c mice which did not show any change in hematology and serum biochemical analysis, which proved the non-toxic nature of D-SNP. Thus, D-SNP can be efficiently used for CT imaging of solid tumors.