Dynamics of Human Serum Albumin Corona Formation on Gold Nanorods with Different Surface Ligands In Silico.

The interaction between human serum albumin (HSA) and nanoparticles (NPs) to form HSA corona has widely been studied since endogenous functions of albumin are highly attractive for drug delivery. However, a full understanding of the molecular dynamics and factors behind the formation of HSA corona, including interactions between HSA and different surface ligands and between neighboring HSA molecules, resulting in conformational change of HSA is presently lacking. Here, we assembled 14 HSA molecules around gold nanorods (AuNRs) with different surface chemistries (bare gold surface, cetyltrimethylammonium bromide (CTAB), polystyrene sulfonate (PSS), and polydiallyldimethylammonium chloride (PDADMAC)) in silico and examined the dynamics of HSA corona formation using coarse-grained molecular dynamics for 300 ns of simulation. We observed that PDADMAC, being more flexible than PSS, resulted in all HSA molecules moving toward AuNR-PDADMAC, while the instability of CTAB on AuNR resulted in fewer HSA molecules moving toward AuNR-CTAB compared to AuNR-PSS. HSA molecules around AuNR-PDADMAC also exhibited the largest conformational change in terms of their radius of gyration (Rg) and root mean square deviation (RMSD). In the absence of surface ligands, HSA molecules around the bare AuNR were susceptible to steric hindrance with conformational change observed in terms of their RMSD but not their Rg unlike that of HSA molecules around AuNR-PDADMAC. The insights gained from the inclusion of neighboring HSA molecules in the simulation of corona formation could be more representative than examining a single adsorbed HSA molecule on AuNRs with different surface passivations.