Hydrodynamic interactions and encapsulation of colloidal nanoparticles by viral coat
proteins
Type: computational project
Contacts: Jens Harting (MTP, e-mail: [email protected]) and Paul van der Schoot (TPS,
e-mail: [email protected])
Simple viruses typically consist of many copies of one or a few kinds of coat protein that
under appropriate conditions self-assemble into a spherical shell around its genome, a singlestranded RNA molecule. Driving force for the spontaneous assembly is provided by
electrostatic interactions between the positively charged proteins and the negatively charged
RNA. Not surprisingly, virus proteins encapsulate not only their native RNAs but also nonnative RNAs, synthetic polyelectrolytes and surface-functionalised nanoparticles, including
magnetic beads, quantum dots and gold particles. Encapsulation of nanoparticles is of great
technological interest in the context of biocompatibilisation, controlled drug delivery and
magnetic imaging applications. How precisely the proteins reversibly bind to the
nanoparticles and cover them is poorly understood, yet is essential in order to optimise
encapsulation strategies.
The aim of the project is to improve this state of affairs by means of computer simulations,
focusing on the role of hydrodynamic interactions between the proteins and the gold
nanoparticle. Hydrodynamic interactions are thought to slow down assembly and prevent
kinetic trapping into misassembled virus-like particles. An existing combined Lattice
Boltzmann and Molecular Dynamics simulation code will be extended to properly include the
electrostatic interactions between the coat proteins and the to be encapsulated nanoparticle.
Starting with studying the interplay between electrostatic interactions and long range
hydrodynamic forces between individual proteins or single proteins with a nanoparticle, the
final goal of the project is to focus on the self-assembly of the protein shell around a
nanoparticle. By modifying the properties of the solvent (e.g. viscosity, temperature,...) and
the electrostatic properties of the particles, we will contribute to the understanding of the selfassembly process itself and how to optimize it for practical applications.:
(Left) Electron micrograph of magnetic nanoparticles encapsulated by the coat protein of a plant
virus, with as inset a single virus-like particle, dark: magnetic nanoparticle, light: virus coat
encapsulating the nanoparticle. (Right) Magnetic Resonance image of virus invasion in plant leaf
using virus-like particles with magnetic nanoparticles. Images taken from Huang et al. ACS
Nano 5 (2012), 4037.