Bismuth nanocolloid or BIB refers to organic bismuth encapsulated in phospholipid core for use as a contrast agent. The Ocean NanoTech’s bismuth nanocolloid (BIB) can be used as a contrast agent for imaging modalities like Spectral computed tomography (CT), CT and X-ray. The BIB offers higher content of bismuth per nanocolloid due to our unique preparation method. This nanocolloid is compatible with various buffers and cell culture media. The zeta potential of plain BIB is around -20- -30 mV indicating good colloidal stability.