"Molecular Dynamics Simulations of Nanostructures Formed by Hydrophobin" by Andrés A. Vodopivec, Yuwu Chen et al.

Faculty Publications

Title

Molecular Dynamics Simulations of Nanostructures Formed by Hydrophobins and Oil in Seawater

Authors

Andrés A. Vodopivec, Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States.
Yuwu Chen, Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Paul S. Russo, School of Materials Science and Engineering and School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Francisco R. Hung, Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States.

Document Type

Article

Publication Date

7-22-2021

Abstract

Classical molecular dynamics simulations using the Martini coarse-grained force field were performed to study oil nanodroplets surrounded by fungal hydrophobin (HP) proteins in seawater. The class I EAS and the class II HFBII HPs were studied along with two model oils, namely, benzene and -decane. Both HPs exhibit free energy minima at the oil-seawater interface, which is deeper in benzene compared to the -decane systems. Larger constraint forces are required to keep both HPs within the -decane phase compared to inside benzene, with HFBII being more affine to benzene compared to EAS. Smaller surface tensions are observed at benzene-seawater interfaces coated with HPs compared to their -decane counterparts. In the latter the surface tension remains unchanged upon increases in the concentration of HPs, whereas in benzene systems adding more HPs lead to decreases in surface tension. EAS has a larger tendency to cluster together in the interface compared to HFBII, with both HPs having larger coordination numbers when surrounding benzene droplets compared to when they are around -decane nanoblobs. The HP-oil nanostructures in seawater examined have radii of gyration ranging between 2 and 12 nm, where the -decane structures are larger and have more irregular shapes compared to the benzene systems. The -decane molecules within the nanostructures form a compact spherical core, with the HPs partially covering its surface and clustering together, conferring irregular shapes to the nanostructures. The EAS with -decane structures are larger and have more irregular shapes compared to their HFBII counterparts. In contrast, in the HP-benzene structures both HPs tend to penetrate the oil part of the droplet. The HFBII-benzene structures having the larger oil/HP ratios examined tend to be more compact and spherical compared to their EAS counterparts; however, some of the HFBII-benzene systems that have smaller oil/HP ratios have a more elongated structure compared to their EAS counterparts. This simulation study provides insights into HP-oil nanostructures that are smaller than the oil droplets and gas bubbles recently studied in experiments and, thus, might be challenging to examine with experimental techniques.

Publication Source (Journal or Book title)

The journal of physical chemistry. B

First Page

7886

Last Page

7899

Recommended Citation

Vodopivec, A. A., Chen, Y., Russo, P. S., & Hung, F. R. (2021). Molecular Dynamics Simulations of Nanostructures Formed by Hydrophobins and Oil in Seawater. The journal of physical chemistry. B, 125 (28), 7886-7899. https://doi.org/10.1021/acs.jpcb.1c02040

This document is currently not available here.

COinS