Large Scale Molecular Simulation of Nanoparticle-Biomolecule Interactions
Ruhong Zhou, IBM Watson Research Center

Nanoscale particles have become promising materials in various biomedical applications, however, in order to stimulate and facilitate these applications, there is an urgent need for a better understanding of their biological effects and underlying physics. In this talk, I will discuss some of our recent works, mostly molecular modelling, at bio-nano interface and their underlying molecular mechanism. We show that carbon-based nanoparticles (carbon nanotubes, graphene nanosheets, and fullerenes) can interact and disrupt the structures and functions of many important proteins. The hydrophobic interactions between the carbon nanotubes and hydrophobic residues, particularly aromatic residues through the so-called pi-pi stacking interactions, are found to play key roles. Meanwhile, metallofullerenol Gd@C82(OH)22 is found to inhibit tumour growth and metastases with both experimental and theoretical approaches. Graphene and graphene oxide (GO) nanosheets show strong destructive interactions to E. coli cell membranes (antibacterial activity) with unique molecular mechanisms, while PEGylated GO nanosheets stimulate potent cytokine responses in peritoneal macrophages. On the other hand, GO nanosheets also show a strong supportive role in enzyme immobilisation such as lipases through lid opening. In particular, the lid opening is assisted by lipase's sophisticated interaction with GO, which allows the adsorbed lipase to enhance its enzyme activity. The lipase enzymatic activity can be further optimized through fine tuning of the GO surface hydrophobicity. These findings might provide a better understanding the underlying physics at bio-nano interface, with implications in future de novo nanomedicine design.