Metaparticles: Computationally engineered nanomaterials with tunable and responsive properties.

In simulations, particles are traditionally treated as rigid platforms with variable sizes, shapes, and interaction parameters. While this representation is applicable for rigid core platforms, particles consisting of soft platforms (e.g., micelles, polymers, elastomers, and lipids) inevitably deform upon application of external stress. We introduce a generic model for flexible particles, which we refer to as MetaParticles (MPs). These particles have tunable properties, can respond to applied tension, and can deform. A MP is represented as a collection of Lennard-Jones beads interconnected by spring-like potentials. We model a series of MPs of variable sizes and symmetries, which we subject to external stress, followed by relaxation upon stress release. The positions and the orientations of the individual beads are propagated by Brownian dynamics. The simulations show that the mechanical properties of the MPs vary with size, bead arrangement, and area of applied stress, and share an elastomer-like response to applied stress. Furthermore, MPs deform following different mechanisms, i.e., small MPs change shape in one step, while larger ones follow a multi-step deformation pathway, with internal rearrangements of the beads. This model is the first step toward the development and understanding of particles with adaptable properties with applications in the biomedical field and in the design of bioinspired metamaterials.