In this study, we synthesised iron oxide nanocrystals (Fe2O3-NC) from goat blood (bio-precursor) using red blood cells (RBC) lysis method (a molecular level approach) for the first time. The formation of Fe2O3-NC was achieved through a single-phase chemical reduction method. The size distribution of Fe2O3-NC falls between 20-30 nm for pellet and 100-200 nm for lysate and were found to be crystalline. Fe2O3-NC demonstrated significant cytotoxicity on A549. We report the direct visualization of interactions between Fe2O3-NC and the cancer cell nucleus. The active transport of Fe2O3-NC to the nucleus induces major changes to nuclear phenotype via nuclear envelope invaginations. We further examined the root cause for the involvement of Fe2O3-NC on the expression of caspase-3, caspase-7 and Bcl-2 in A549 cancer cells. This functional proteomic analysis clearly implies that the lung cancer cell proliferation is perfectly targeted by the biosynthesised Fe2O3-NC which could provide new insight for nuclear-targeted cancer therapy. (C) 2013 Elsevier Ltd. All rights reserved.