Bridging the gap between atomistic detail and continuum mechanics is a central challenge in modeling biological membranes, particularly for mesoscopic phenomena spanning large length and time scales. MesoMem is a solvent-free, one-particle-thick coarse-grained model for lipid bilayers governed by an additive potential that treats orientational elasticity through distinct tilt and splay energy terms. The model is implemented as a custom pair-style in the LAMMPS molecular dynamics engine and is freely available.

Key Features

Additive Potential

Orientational elasticity is split into independent tilt and splay energy terms, offering an unbiased potential form and direct physical interpretation of each contribution to membrane mechanics.

Mesoscale Efficiency

Each particle represents a bilayer patch of ~300 lipids. The model accesses microsecond timescales and micron-scale membrane areas — far beyond what atomistic or standard coarse-grained models can reach.

LAMMPS Implementation

Implemented as a custom pair-style in LAMMPS, with full support for MPI parallelization. The source code, example scripts, and tutorials are openly available on GitLab.

Overview of Simulated Systems

Overview of MesoMem simulated lipid systems
Fig. 3 — Overview of simulated lipid systems. (A) Self-assembled patches from 1500 randomly placed particles. (B) Planar membrane colored by z-height. (C) Vesicle with zero (red) and non-zero spontaneous curvature C₀ = 0.1 σ⁻¹ (blue) beads undergoing phase separation. (D) Spherical vesicle: cross-section (top) and full vesicle (bottom). (E) Membrane tube. (F) Cross-section of a vesicle wrapping a colloidal particle. (G) Planar membrane interacting with soft colloidal metaparticles.

Physics Covered

Self-Assembly & Vesiculation

Particles spontaneously assemble into lamellar structures and close into stable vesicles from a disordered state.

Tunable Mechanics

Bending rigidities in the biologically relevant range of 10–30 k_BT and area compressibility moduli calibratable to experimental values.

Rich Extensions

Supports spontaneous curvature, osmotic pressure via explicit solvent particles, multiple lipid types, and adhesive interactions with colloidal nanoparticles.

Getting Started

Clone the repository and follow the build instructions to compile LAMMPS with the MesoMem pair-style:

git clone https://gitlab.tudelft.nl/idema-group/MesoMem
cd MesoMem
# See README for LAMMPS build instructions

Full example scripts are available in the GitLab repository.

Tutorials

Citation

@misc{sillano2026mesomem,
  title         = {MesoMem: A mesoscale membrane model based on an additive potential},
  author        = {Pietro Sillano and Siewert Jan Marrink and Timon Idema},
  year          = {2026},
  eprint        = {2602.24123},
  archivePrefix = {arXiv},
  primaryClass  = {cond-mat.soft},
  url           = {https://arxiv.org/abs/2602.24123}
}