The interaction of bovine serum albumin with doxorubicin-loaded superparamagnetic iron oxide nanoparticles: spectroscope and molecular modelling identification.

To take a comprehensive evaluation of the bio-safety of doxorubicin-loaded superparamagnetic iron oxide nanoparticles (SPION), the interaction of bovine serum albumin (BSA) with the drug delivery was investigated by multi-spectroscopic techniques and molecular modelling calculation. Ultraviolet absorption and synchronous fluorescence results elucidate that DOX-SPION unfold the framework conformation of BSA, leading to changes in the microenvironment of amide moieties. Circular dichroism (CD) data show that the content of α-helix decreases from 68.62% to 62.76%, which shows the changes of protein's secondary structure quantificationally. Through Stern-Volmer analysis, the quenching mode is determined to be static interaction, forming a stable bioconjugate. The molecular model illustrates that DOX prefers a highly polar binding site at the external region of domains □ of BSA, and the hydrogen bonds are marked. This work elucidates that the drug delivery has deleterious effects on the frame conformation of protein, affecting its physiological function.